Kea DHCPのHigh-Availabilityを検証する - (2)Act-ActのLoad-Balancing構成を組む

ゴール

Kea DHCPを用いてAct-ActのLoad-Balancing High-Availability構成を組み，動作させることができること．

Kea DHCPでLoad-BalancibngモードのHA構成を組む

Introduction

前回，Kea DHCPでhot-standby構成のHA構成を組む方法について紹介をした． 今回はhot-standbyではないもう一つの方法であるload-balancingモードでのHA構成を組んでみる．

検証条件は前回と同様(dockerfile, IPアドレスや本記事で紹介しないconfigなどすべて)であるので，kea自体の紹介や，環境構築等については前回の記事を参照してほしい． 本記事ではhot-standbyとload-balancingモードの違いについて特に焦点を当てて紹介する．

configuration

早速configを行なっていく． load-balancingモードの利用に伴い，modeや 各peer config内のroleが異なってくる． load-balancingモードでkea_1をprimary, kea_2をsecondaryとする場合，configは下記のようになる．

this-server-name: kea_1 //(2台目は"kea_2")
mode: load-balancing
heartbeat-delay: 10000
max-response-delay: 60000
max-ack-delay: 10000
max-unacked-clients: 0
"peers": [
  {
    "name": "kea_1",
    "url": "http://172.18.0.3:8080/",
    "role": "primary",
    "auto-failover": true
  },
  {
    "name": "kea_2",
    "url": "http://172.18.0.2:8080/",
    "role": "secondary",
    "auto-failover": true
  }
]

上記を踏まえてconfigを作成し，各サーバに適用して動作を確認してみよう．
たとえば私の検証では下記のようなconfigをkea_1に投入した．kea_2もほぼ同様であるが，"this-server-name" 等を適切に変更する．

root@085fd121c5c6:~# cat /usr/local/etc/kea/kea-dhcp4.conf
{
"Dhcp4": {
    "interfaces-config": {
        "interfaces": ["eth0"],
        "dhcp-socket-type": "raw",
        "outbound-interface": "use-routing"
    },
    "control-socket": {
        "socket-type": "unix",
        "socket-name": "/tmp/kea-dhcp4-ctrl.sock"
    },
    "lease-database": {
        "type": "memfile",
        "persist": true,
        "name": "/usr/local/etc/kea/kea-leases4.csv",
        "lfc-interval": 1800
    },
    "expired-leases-processing": {
        "reclaim-timer-wait-time": 10,
        "flush-reclaimed-timer-wait-time": 25,
        "hold-reclaimed-time": 3600,
        "max-reclaim-leases": 100,
        "max-reclaim-time": 250,
        "unwarned-reclaim-cycles": 5
    },

    "renew-timer": 1200,
    "rebind-timer": 2400,
    "valid-lifetime": 3600,

    "option-data": [
        {
            "name": "domain-name-servers",
            "data": "8.8.8.8, 8.8.4.4"
        },
        {
            "name": "default-ip-ttl",
            "data": "0xf0"
        }
    ],

    "hooks-libraries": [
        {
            "library": "/usr/local/lib/hooks/libdhcp_lease_cmds.so",
            "parameters": { }
        },
        {
            "library": "/usr/local/lib/hooks/libdhcp_ha.so",
            "parameters": {
                "high-availability": [ {
                    "this-server-name": "kea_1",
                    "mode": "load-balancing",
                    "heartbeat-delay": 10000,
                    "max-response-delay": 10000,
                    "max-ack-delay": 5000,
                    "max-unacked-clients": 5,
                    "peers": [
                      {
                        "name": "kea_1",
                        "url": "http://172.18.0.3:8080/",
                        "role": "primary",
                        "auto-failover": true
                      },
                      {
                        "name": "kea_2",
                        "url": "http://172.18.0.2:8080/",
                        "role": "secondary",
                        "auto-failover": true
                      }
                    ]
                } ]
            }
        }
    ],

    "reservation-mode": "disabled",
    "host-reservation-identifiers": [ "hw-address" ],

    "subnet4": [
          {
                "id": 1,
                "subnet": "172.18.0.0/16",
                "pools": [
                    { "pool": "172.18.0.100 - 172.18.0.250" }
                ],
                "option-data": [
                    {
                        "name": "routers",
                        "data": "172.18.0.1"
                    }
                ]
          }
    ]
},

"Logging":
{
  "loggers": [
    {
        "name": "kea-dhcp4",
        "output_options": [
            {
                "output": "/usr/local/var/log/kea-dhcp4.log",
                "maxver": 8,
                "maxsize": 204800,
                "flush": true
            }
        ],
        "severity": "DEBUG",
        "debuglevel": 99
    }
  ]
}
}

まずはkea_1でkeaを起動する．今回，起動にはkeactrlコマンドを用いた． 起動後にRESTAPIでha-heartbeatを送信していることと，それぞれのサーバのステータスを見てみよう．

# kea_1
root@085fd121c5c6:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.3:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0curl: (7) Failed to connect to 172.18.0.3 port 8080: Connection refused
root@085fd121c5c6:~# keactrl start
INFO/keactrl: Starting /usr/local/sbin/kea-dhcp4 -c /usr/local/etc/kea/kea-dhcp4.conf
INFO/keactrl: Starting /usr/local/sbin/kea-ctrl-agent -c /usr/local/etc/kea/kea-ctrl-agent.conf
root@085fd121c5c6:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.3:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   191  100   138  100    53  34500  13250 --:--:-- --:--:-- --:--:-- 63666
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:56:46 GMT",
      "state": "waiting"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]
root@085fd121c5c6:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.3:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   196  100   143  100    53  11916   4416 --:--:-- --:--:-- --:--:-- 17818
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:56:50 GMT",
      "state": "partner-down"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]

起動後，kea_1はstateが waitingから，partner-downにシフトしていることが見受けられる． kea_1を起動し，kea_2を起動していない場合，kea_1はこの状態(partner-down)に収束する．

ここでkea_2を起動する．

# kea_2
root@05e1a4a4476e:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.2:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0curl: (7) Failed to connect to 172.18.0.2 port 8080: Connection refused
root@05e1a4a4476e:~# keactrl start
INFO/keactrl: Starting /usr/local/sbin/kea-dhcp4 -c /usr/local/etc/kea/kea-dhcp4.conf
INFO/keactrl: Starting /usr/local/sbin/kea-ctrl-agent -c /usr/local/etc/kea/kea-ctrl-agent.conf
root@05e1a4a4476e:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.2:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--   100   191  100   138  100    53  46000  17666 --:--:-- --:--:-- --:--:-- 95500
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:57:12 GMT",
      "state": "waiting"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]
root@05e1a4a4476e:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.2:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--   100   191  100   138  100    53  34500  13250 --:--:-- --:--:-- --:--:-- 63666
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:57:20 GMT",
      "state": "waiting"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]
root@05e1a4a4476e:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.2:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--   100   189  100   136  100    53  12363   4818 --:--:-- --:--:-- --:--:-- 21000
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:57:32 GMT",
      "state": "ready"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]
root@05e1a4a4476e:~# curl -X POST -H "Content-Type: application/json" -d '{ "command": "ha-heartbeat", "service": [ "dhcp4" ] }' http://172.18.0.2:8080/ | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--   100   198  100   145  100    53   7250   2650 --:--:-- --:--:-- --:--:--  9900
[
  {
    "arguments": {
      "date-time": "Wed, 20 Nov 2019 06:57:36 GMT",
      "state": "load-balancing"
    },
    "result": 0,
    "text": "HA peer status returned."
  }
]

ログを見てみる．

# kea_1
root@085fd121c5c6:/# grep INFO /usr/local/var/log/kea-dhcp4.log | grep ha-hooks
2019-11-20 06:56:39.814 INFO  [kea-dhcp4.ha-hooks/387] HA_CONFIGURATION_SUCCESSFUL HA hook library has been successfully configured
2019-11-20 06:56:39.814 INFO  [kea-dhcp4.ha-hooks/387] HA_INIT_OK loading High Availability hooks library successful
2019-11-20 06:56:39.884 INFO  [kea-dhcp4.ha-hooks/387] HA_LOCAL_DHCP_DISABLE local DHCP service is disabled while the kea_1 is in the WAITING state
2019-11-20 06:56:39.884 INFO  [kea-dhcp4.ha-hooks/387] HA_SERVICE_STARTED started high availability service in load-balancing mode as primary server
2019-11-20 06:56:50.323 INFO  [kea-dhcp4.ha-hooks/387] HA_STATE_TRANSITION server transitions from WAITING to PARTNER-DOWN state, partner state is UNDEFINED
2019-11-20 06:56:50.323 INFO  [kea-dhcp4.ha-hooks/387] HA_LEASE_UPDATES_DISABLED lease updates will not be sent to the partner while in PARTNER-DOWN state
2019-11-20 06:56:50.323 INFO  [kea-dhcp4.ha-hooks/387] HA_LOCAL_DHCP_ENABLE local DHCP service is enabled while the kea_1 is in the PARTNER-DOWN state
2019-11-20 06:57:33.825 INFO  [kea-dhcp4.ha-hooks/387] HA_STATE_TRANSITION server transitions from PARTNER-DOWN to LOAD-BALANCING state, partner state is READY
2019-11-20 06:57:33.825 INFO  [kea-dhcp4.ha-hooks/387] HA_LEASE_UPDATES_ENABLED lease updates will be sent to the partner while in LOAD-BALANCING state
root@085fd121c5c6:/#

# kea_2
root@05e1a4a4476e:/# grep INFO /usr/local/var/log/kea-dhcp4.log | grep ha-hooks
2019-11-20 06:57:11.496 INFO  [kea-dhcp4.ha-hooks/512] HA_CONFIGURATION_SUCCESSFUL HA hook library has been successfully configured
2019-11-20 06:57:11.496 INFO  [kea-dhcp4.ha-hooks/512] HA_INIT_OK loading High Availability hooks library successful
2019-11-20 06:57:11.528 INFO  [kea-dhcp4.ha-hooks/512] HA_LOCAL_DHCP_DISABLE local DHCP service is disabled while the kea_2 is in the WAITING state
2019-11-20 06:57:11.528 INFO  [kea-dhcp4.ha-hooks/512] HA_SERVICE_STARTED started high availability service in load-balancing mode as secondary server
2019-11-20 06:57:23.295 INFO  [kea-dhcp4.ha-hooks/512] HA_STATE_TRANSITION server transitions from WAITING to SYNCING state, partner state is PARTNER-DOWN
2019-11-20 06:57:23.295 INFO  [kea-dhcp4.ha-hooks/512] HA_LEASE_UPDATES_DISABLED lease updates will not be sent to the partner while in SYNCING state
2019-11-20 06:57:23.295 INFO  [kea-dhcp4.ha-hooks/512] HA_SYNC_START starting lease database synchronization with kea_1
2019-11-20 06:57:23.306 INFO  [kea-dhcp4.ha-hooks/512] HA_LEASES_SYNC_LEASE_PAGE_RECEIVED received 0 leases from kea_1
2019-11-20 06:57:23.308 INFO  [kea-dhcp4.ha-hooks/512] HA_SYNC_SUCCESSFUL lease database synchronization with kea_1 completed successfully in 12.135 ms
2019-11-20 06:57:23.308 INFO  [kea-dhcp4.ha-hooks/512] HA_STATE_TRANSITION server transitions from SYNCING to READY state, partner state is PARTNER-DOWN
2019-11-20 06:57:23.308 INFO  [kea-dhcp4.ha-hooks/512] HA_LEASE_UPDATES_DISABLED lease updates will not be sent to the partner while in READY state
2019-11-20 06:57:34.860 INFO  [kea-dhcp4.ha-hooks/512] HA_STATE_TRANSITION server transitions from READY to LOAD-BALANCING state, partner state is LOAD-BALANCING
2019-11-20 06:57:34.860 INFO  [kea-dhcp4.ha-hooks/512] HA_LEASE_UPDATES_ENABLED lease updates will be sent to the partner while in LOAD-BALANCING state
2019-11-20 06:57:34.860 INFO  [kea-dhcp4.ha-hooks/512] HA_LOCAL_DHCP_ENABLE local DHCP service is enabled while the kea_2 is in the LOAD-BALANCING state
root@05e1a4a4476e:/#

これらをみてみると，起動直後，これらのHAは下記のような順序で状態遷移していることがわかる．

2019-11-20 06:56:39.884:: kea_1: waiting     , kea_2: UNDEFINED
2019-11-20 06:56:50.323:: kea_1: partner-down, kea_2: UNDEFINED
2019-11-20 06:57:11.528:: kea_1: partner-down, kea_2: waiting
2019-11-20 06:57:23.295:: kea_1: partner-down, kea_2: syncing
2019-11-20 06:57:23.308:: kea_1: partner-down, kea_2: ready
2019-11-20 06:57:33.825:: kea_1: load-balancing,  kea_2: ready
2019-11-20 06:57:34.860:: kea_1: load-balancing , kea_2: load-balancing

このそれぞれのstateの意味はkeaのdocumentを参照していただくのがbestだと思うが，前回の記事でも簡単に説明しているので参考になるかもしれない．

load-balancingモードでのDHCPリース動作

HA構成を組むことができていることが確認できたので，この状態でDHCPのアドレスリースを行い，HA構成に受けるアドレスリース時の振る舞いを確認していこうと思う．

DHCPリースを模擬するために，前回同様，dhtestを利用した．

load-balancingモードでHA構成が組まれたサーバ群が接続されているNW上に存在するdhtest用VMで，下記の通りコマンドを実行する．

./dhtest -i <interface> -m <mac_addr>

mac_addrはdhtestホストから送出するDHCPパケットのchaddrフィールドに入るMACアドレスと思えばよい． これを数回繰り返し実施した時の振る舞いを見てみる． dhtestホストでは下記のようにアドレスリースが模擬できているようである．

[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:33
DHCP discover sent   - Client MAC : 00:00:00:11:22:33
DHCP offer received  - Offered IP : 172.18.0.100
DHCP request sent  - Client MAC : 00:00:00:11:22:33
DHCP ack received  - Acquired IP: 172.18.0.100
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:34
DHCP discover sent   - Client MAC : 00:00:00:11:22:34
DHCP offer received  - Offered IP : 172.18.0.101
DHCP request sent  - Client MAC : 00:00:00:11:22:34
ADHCP ack received  - Acquired IP: 172.18.0.101
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:35
DHCP discover sent   - Client MAC : 00:00:00:11:22:35
DHCP offer received  - Offered IP : 172.18.0.102
DHCP request sent  - Client MAC : 00:00:00:11:22:35
DHCP ack received  - Acquired IP: 172.18.0.102
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:36
DHCP discover sent   - Client MAC : 00:00:00:11:22:36
DHCP offer received  - Offered IP : 172.18.0.103
DHCP request sent  - Client MAC : 00:00:00:11:22:36
DHCP ack received  - Acquired IP: 172.18.0.103
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:37
DHCP discover sent   - Client MAC : 00:00:00:11:22:37
DHCP offer received  - Offered IP : 172.18.0.104
DHCP request sent  - Client MAC : 00:00:00:11:22:37
DHCP ack received  - Acquired IP: 172.18.0.104
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:38
DHCP discover sent   - Client MAC : 00:00:00:11:22:38
DHCP offer received  - Offered IP : 172.18.0.105
DHCP request sent  - Client MAC : 00:00:00:11:22:38
DHCP ack received  - Acquired IP: 172.18.0.105
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:39
DHCP discover sent   - Client MAC : 00:00:00:11:22:39
DHCP offer received  - Offered IP : 172.18.0.106
DHCP request sent  - Client MAC : 00:00:00:11:22:39
DHCP ack received  - Acquired IP: 172.18.0.106
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:40
DHCP discover sent   - Client MAC : 00:00:00:11:22:40
DHCP offer received  - Offered IP : 172.18.0.107
DHCP request sent  - Client MAC : 00:00:00:11:22:40
DHCP ack received  - Acquired IP: 172.18.0.107
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:41
DHCP discover sent   - Client MAC : 00:00:00:11:22:41
DHCP offer received  - Offered IP : 172.18.0.108
DHCP request sent  - Client MAC : 00:00:00:11:22:41
DHCP ack received  - Acquired IP: 172.18.0.108
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:42
DHCP discover sent   - Client MAC : 00:00:00:11:22:42
DHCP offer received  - Offered IP : 172.18.0.109
DHCP request sent  - Client MAC : 00:00:00:11:22:42
DHCP ack received  - Acquired IP: 172.18.0.109
[root@a50202e240fb dhtest-master]# ./dhtest -i eth0 -m 00:00:00:11:22:43
DHCP discover sent   - Client MAC : 00:00:00:11:22:43
DHCP offer received  - Offered IP : 172.18.0.110
DHCP request sent  - Client MAC : 00:00:00:11:22:43
DHCP ack received  - Acquired IP: 172.18.0.110
[root@a50202e240fb dhtest-master]#

この時，kea_1 とkea_2 ホストでパケットキャプチャを行うと．

## kea_1
root@085fd121c5c6:/# tcpdump -i eth0 port 67 or port 68 -v
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
^[[O06:59:13.512449 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:33 (oui Ethernet), length 251, xid 0x2960582c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:13.552499 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:33 (oui Ethernet), length 263, xid 0x2960582c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.100
      Server-ID Option 54, length 4: kea_2.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:18.869778 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:34 (oui Ethernet), length 251, xid 0x31c40ac1, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:18.871641 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    085fd121c5c6.bootps > 172.18.0.101.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x31c40ac1, Flags [none]
    Your-IP 172.18.0.101
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 085fd121c5c6
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:18.872159 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:34 (oui Ethernet), length 263, xid 0x31c40ac1, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.101
      Server-ID Option 54, length 4: 085fd121c5c6
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:19.878008 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    085fd121c5c6.bootps > 172.18.0.101.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x31c40ac1, Flags [none]
    Your-IP 172.18.0.101
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: ACK
      Server-ID Option 54, length 4: 085fd121c5c6
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:22.559720 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:35 (oui Ethernet), length 251, xid 0x4c120d1c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:35 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:22.563249 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:35 (oui Ethernet), length 263, xid 0x4c120d1c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:35 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.102
      Server-ID Option 54, length 4: kea_2.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:26.252357 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:36 (oui Ethernet), length 251, xid 0x671e7d0f, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:36 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:26.265846 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:36 (oui Ethernet), length 263, xid 0x671e7d0f, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:36 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.103
      Server-ID Option 54, length 4: kea_2.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:38.855959 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:40 (oui Ethernet), length 251, xid 0x16e71cb, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:38.857611 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    085fd121c5c6.bootps > 172.18.0.107.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x16e71cb, Flags [none]
    Your-IP 172.18.0.107
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 085fd121c5c6
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:38.857778 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:40 (oui Ethernet), length 263, xid 0x16e71cb, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.107
      Server-ID Option 54, length 4: 085fd121c5c6
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:39.859876 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    085fd121c5c6.bootps > 172.18.0.107.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x16e71cb, Flags [none]
    Your-IP 172.18.0.107
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: ACK
      Server-ID Option 54, length 4: 085fd121c5c6
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:41.995310 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:41 (oui Ethernet), length 251, xid 0x44f61b6e, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:41 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:41.996738 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    085fd121c5c6.bootps > 172.18.0.108.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x44f61b6e, Flags [none]
    Your-IP 172.18.0.108
    Client-Ethernet-Address 00:00:00:11:22:41 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 085fd121c5c6
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:46.075757 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:42 (oui Ethernet), length 251, xid 0x4da855db, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:46.078611 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:42 (oui Ethernet), length 263, xid 0x4da855db, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.109
      Server-ID Option 54, length 4: kea_2.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:49.416302 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:43 (oui Ethernet), length 251, xid 0x39e5fa04, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:49.418794 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:43 (oui Ethernet), length 263, xid 0x39e5fa04, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.110
      Server-ID Option 54, length 4: kea_2.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
^C
20 packets captured
32 packets received by filter
12 packets dropped by kernel
root@085fd121c5c6:/#

## kea_2
root@05e1a4a4476e:/# tcpdump -i eth0 port 67 or port 68 -v
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
06:59:13.512513 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:33 (oui Ethernet), length 251, xid 0x2960582c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:13.551115 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.100.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x2960582c, Flags [none]
    Your-IP 172.18.0.100
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:13.552540 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:33 (oui Ethernet), length 263, xid 0x2960582c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.100
      Server-ID Option 54, length 4: 05e1a4a4476e
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:14.559982 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.100.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x2960582c, Flags [none]
    Your-IP 172.18.0.100
    Client-Ethernet-Address 00:00:00:11:22:33 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: ACK
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:18.869813 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:34 (oui Ethernet), length 251, xid 0x31c40ac1, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:18.872189 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:34 (oui Ethernet), length 263, xid 0x31c40ac1, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:34 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.101
      Server-ID Option 54, length 4: kea_1.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:22.559775 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:35 (oui Ethernet), length 251, xid 0x4c120d1c, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:35 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:22.561696 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.102.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x4c120d1c, Flags [none]
    Your-IP 172.18.0.102
    Client-Ethernet-Address 00:00:00:11:22:35 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:38.856100 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:40 (oui Ethernet), length 251, xid 0x16e71cb, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:38.857816 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:40 (oui Ethernet), length 263, xid 0x16e71cb, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:40 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.107
      Server-ID Option 54, length 4: kea_1.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:41.995354 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:41 (oui Ethernet), length 251, xid 0x44f61b6e, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:41 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:41.996990 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:41 (oui Ethernet), length 263, xid 0x44f61b6e, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:41 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.108
      Server-ID Option 54, length 4: kea_1.kea-mng
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:46.075816 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:42 (oui Ethernet), length 251, xid 0x4da855db, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:46.077736 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.109.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x4da855db, Flags [none]
    Your-IP 172.18.0.109
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:46.078692 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:42 (oui Ethernet), length 263, xid 0x4da855db, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.109
      Server-ID Option 54, length 4: 05e1a4a4476e
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:47.091865 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.109.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x4da855db, Flags [none]
    Your-IP 172.18.0.109
    Client-Ethernet-Address 00:00:00:11:22:42 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: ACK
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:49.416473 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 279)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:43 (oui Ethernet), length 251, xid 0x39e5fa04, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Discover
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:49.418437 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.110.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x39e5fa04, Flags [none]
    Your-IP 172.18.0.110
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: Offer
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
06:59:49.418845 IP (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 291)
    0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:00:00:11:22:43 (oui Ethernet), length 263, xid 0x39e5fa04, Flags [none]
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      DHCP-Message Option 53, length 1: Request
      Requested-IP Option 50, length 4: 172.18.0.110
      Server-ID Option 54, length 4: 05e1a4a4476e
      Parameter-Request Option 55, length 5:
        Subnet-Mask, BR, Default-Gateway, Domain-Name
        Domain-Name-Server
06:59:50.424369 IP (tos 0x10, ttl 128, id 0, offset 0, flags [DF], proto UDP (17), length 318)
    05e1a4a4476e.bootps > 172.18.0.110.bootpc: BOOTP/DHCP, Reply, length 290, xid 0x39e5fa04, Flags [none]
    Your-IP 172.18.0.110
    Client-Ethernet-Address 00:00:00:11:22:43 (oui Ethernet)
    Vendor-rfc1048 Extensions
      Magic Cookie 0x63825363
      Subnet-Mask Option 1, length 4: 255.255.0.0
      Default-Gateway Option 3, length 4: 172.18.0.1
      Domain-Name-Server Option 6, length 8: dns.google,dns.google
      Lease-Time Option 51, length 4: 3600
      DHCP-Message Option 53, length 1: ACK
      Server-ID Option 54, length 4: 05e1a4a4476e
      RN Option 58, length 4: 1200
      RB Option 59, length 4: 2400
^C
20 packets captured
34 packets received by filter
14 packets dropped by kernel
root@05e1a4a4476e:/#

これら2つのパケットキャプチャをみて理解できるとおり， kea_1でもkea_2でも，はクライアントからのDHCP要求(DISCOVERY, REQUEST)において，クライアントに対してOFFER, ACK を返していることがわかる． これはHAモードのうち，両方のサーバがDHCPに応答するload-balancingの動作となっていることがわかる． ただし，kea_1とkea_2が完全に1回ごとに交互にリース動作をするのではなく，複数回同じserverが連続して応答することもあることが見て取れる． これはKea DHCPのload-balancingがRFC3074に基づいて実装されているからであるように見受けられる． RFC3074によると，DHCPDISCOVERパケットのある値からハッシュを取り，その値は0-255の値をとる．ロードバランシング構成がとられたそれぞれのサーバではあるテーブルをもつ．それは自分が応答するべき値が1となるように構成された32bytesのテーブルである(32 * 8 = 256)．この256ビットのテーブルと，DHCPDISCOVERパケットから計算されたハッシュ値を比較し，自分が応答すべき場合にのみDHCPOFFERパケットを送付して応答するロジックとなっているようだ．そのため，マクロ的，長期的にみると設計された負荷分散率となるが，ミクロ的，短時間的にみると偏りが生まれる可能性は十分に考えられる．今回繰り返して同一のサーバが応答したこともこの特徴的なアルゴリズムの振る舞いによるものだと考えることができるだろう．

• 追記: RFC3074を和訳しました．RFC 3074を読んでみた話 - JP7FKFの備忘録
• ref: Kea High Availability vs ISC DHCP Failover - Kea DHCP

またこの時のlease-updateを見てみよう．

## kea_1

06:59:13.558097 IP (tos 0x0, ttl 64, id 5427, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x1fc4), seq 124:477, ack 255, win 321, options [nop,nop,TS val 7878270 ecr 7878004], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236753, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:33", "ip-address": "172.18.0.100", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:13.568131 IP (tos 0x0, ttl 64, id 176, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x5eef), seq 255:411, ack 477, win 235, options [nop,nop,TS val 7878271 ecr 7878270], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:13 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:13.568225 IP (tos 0x0, ttl 64, id 5428, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x2781), ack 411, win 329, options [nop,nop,TS val 7878271 ecr 7878271], length 0
06:59:17.049416 IP (tos 0x0, ttl 64, id 24059, offset 0, flags [DF], proto TCP (6), length 176)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x7191), seq 124:248, ack 255, win 312, options [nop,nop,TS val 7878620 ecr 7877403], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:17.053342 IP (tos 0x0, ttl 64, id 6822, offset 0, flags [DF], proto TCP (6), length 306)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x594e (incorrect -> 0xdb0c), seq 255:509, ack 248, win 227, options [nop,nop,TS val 7878620 ecr 7878620], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:17 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:17 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:17.053369 IP (tos 0x0, ttl 64, id 24060, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xf4b4), ack 509, win 321, options [nop,nop,TS val 7878620 ecr 7878620], length 0
06:59:18.874313 IP (tos 0x0, ttl 64, id 24061, offset 0, flags [DF], proto TCP (6), length 405)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xe230), seq 248:601, ack 509, win 321, options [nop,nop,TS val 7878802 ecr 7878620], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236758, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:34", "ip-address": "172.18.0.101", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:18.877715 IP (tos 0x0, ttl 64, id 6823, offset 0, flags [DF], proto TCP (6), length 208)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x28ac), seq 509:665, ack 601, win 235, options [nop,nop,TS val 7878802 ecr 7878802], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:18 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:18.877843 IP (tos 0x0, ttl 64, id 24062, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xf143), ack 665, win 329, options [nop,nop,TS val 7878802 ecr 7878802], length 0
06:59:22.561975 IP (tos 0x0, ttl 64, id 5429, offset 0, flags [DF], proto TCP (6), length 176)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x9a95), seq 477:601, ack 411, win 329, options [nop,nop,TS val 7879171 ecr 7878271], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:22.563407 IP (tos 0x0, ttl 64, id 177, offset 0, flags [DF], proto TCP (6), length 306)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x594e (incorrect -> 0x0f55), seq 411:665, ack 601, win 235, options [nop,nop,TS val 7879171 ecr 7879171], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:22 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:22 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:22.563509 IP (tos 0x0, ttl 64, id 5430, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x1ef7), ack 665, win 337, options [nop,nop,TS val 7879171 ecr 7879171], length 0
06:59:22.574735 IP (tos 0x0, ttl 64, id 5431, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x1127), seq 601:954, ack 665, win 337, options [nop,nop,TS val 7879172 ecr 7879171], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236762, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:35", "ip-address": "172.18.0.102", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:22.584285 IP (tos 0x0, ttl 64, id 178, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x5365), seq 665:821, ack 954, win 243, options [nop,nop,TS val 7879173 ecr 7879172], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:22 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:22.628444 IP (tos 0x0, ttl 64, id 5432, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x1ce8), ack 821, win 346, options [nop,nop,TS val 7879178 ecr 7879173], length 0
06:59:26.274709 IP (tos 0x0, ttl 64, id 5433, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x07ad), seq 954:1307, ack 821, win 346, options [nop,nop,TS val 7879542 ecr 7879173], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236766, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:36", "ip-address": "172.18.0.103", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:26.327869 IP (tos 0x0, ttl 64, id 179, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x4e73), seq 821:977, ack 1307, win 252, options [nop,nop,TS val 7879547 ecr 7879542], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:26 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:26.328036 IP (tos 0x0, ttl 64, id 5434, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x17fc), ack 977, win 354, options [nop,nop,TS val 7879547 ecr 7879547], length 0
06:59:28.296754 IP (tos 0x0, ttl 64, id 24063, offset 0, flags [DF], proto TCP (6), length 176)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x642a), seq 601:725, ack 665, win 329, options [nop,nop,TS val 7879748 ecr 7878802], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:28.298602 IP (tos 0x0, ttl 64, id 6824, offset 0, flags [DF], proto TCP (6), length 306)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x594e (incorrect -> 0xccbb), seq 665:919, ack 725, win 235, options [nop,nop,TS val 7879748 ecr 7879748], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:28 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:28 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:28.298650 IP (tos 0x0, ttl 64, id 24064, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xe85d), ack 919, win 337, options [nop,nop,TS val 7879748 ecr 7879748], length 0
06:59:29.229170 IP (tos 0x0, ttl 64, id 5435, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xfe06), seq 1307:1660, ack 977, win 354, options [nop,nop,TS val 7879841 ecr 7879547], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236769, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:37", "ip-address": "172.18.0.104", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:29.230833 IP (tos 0x0, ttl 64, id 180, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x4a1a), seq 977:1133, ack 1660, win 260, options [nop,nop,TS val 7879841 ecr 7879841], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:29 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:29.230925 IP (tos 0x0, ttl 64, id 5436, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x13aa), ack 1133, win 363, options [nop,nop,TS val 7879841 ecr 7879841], length 0
06:59:32.314046 IP (tos 0x0, ttl 64, id 24065, offset 0, flags [DF], proto TCP (6), length 405)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xd2fc), seq 725:1078, ack 919, win 337, options [nop,nop,TS val 7880149 ecr 7879748], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236772, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:38", "ip-address": "172.18.0.105", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:32.317924 IP (tos 0x0, ttl 64, id 6825, offset 0, flags [DF], proto TCP (6), length 208)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x18ac), seq 919:1075, ack 1078, win 243, options [nop,nop,TS val 7880150 ecr 7880149], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:32 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:32.317973 IP (tos 0x0, ttl 64, id 24066, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xe333), ack 1075, win 346, options [nop,nop,TS val 7880150 ecr 7880150], length 0
06:59:33.319217 IP (tos 0x0, ttl 64, id 5437, offset 0, flags [DF], proto TCP (6), length 176)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x88a9), seq 1660:1784, ack 1133, win 363, options [nop,nop,TS val 7880250 ecr 7879841], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:33.322421 IP (tos 0x0, ttl 64, id 181, offset 0, flags [DF], proto TCP (6), length 306)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x594e (incorrect -> 0xfd5a), seq 1133:1387, ack 1784, win 260, options [nop,nop,TS val 7880250 ecr 7880250], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:33 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:33 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:33.322543 IP (tos 0x0, ttl 64, id 5438, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0ef6), ack 1387, win 371, options [nop,nop,TS val 7880250 ecr 7880250], length 0
06:59:35.557413 IP (tos 0x0, ttl 64, id 24067, offset 0, flags [DF], proto TCP (6), length 405)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc91f), seq 1078:1431, ack 1075, win 346, options [nop,nop,TS val 7880474 ecr 7880150], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236775, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:39", "ip-address": "172.18.0.106", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:35.559028 IP (tos 0x0, ttl 64, id 6826, offset 0, flags [DF], proto TCP (6), length 208)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x141a), seq 1075:1231, ack 1431, win 252, options [nop,nop,TS val 7880474 ecr 7880474], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:35 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:35.559069 IP (tos 0x0, ttl 64, id 24068, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xdea6), ack 1231, win 354, options [nop,nop,TS val 7880474 ecr 7880474], length 0
06:59:38.859078 IP (tos 0x0, ttl 64, id 24069, offset 0, flags [DF], proto TCP (6), length 405)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc98b), seq 1431:1784, ack 1231, win 354, options [nop,nop,TS val 7880804 ecr 7880474], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236778, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:40", "ip-address": "172.18.0.107", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:38.861084 IP (tos 0x0, ttl 64, id 6827, offset 0, flags [DF], proto TCP (6), length 208)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x0f7e), seq 1231:1387, ack 1784, win 260, options [nop,nop,TS val 7880804 ecr 7880804], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:38 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:38.861128 IP (tos 0x0, ttl 64, id 24070, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xda0c), ack 1387, win 363, options [nop,nop,TS val 7880804 ecr 7880804], length 0
06:59:39.860222 IP (tos 0x0, ttl 64, id 24071, offset 0, flags [DF], proto TCP (6), length 176)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x5041), seq 1784:1908, ack 1387, win 363, options [nop,nop,TS val 7880904 ecr 7880804], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:39.864235 IP (tos 0x0, ttl 64, id 6828, offset 0, flags [DF], proto TCP (6), length 306)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x594e (incorrect -> 0xba27), seq 1387:1641, ack 1908, win 260, options [nop,nop,TS val 7880904 ecr 7880904], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:39 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:39 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:39.864285 IP (tos 0x0, ttl 64, id 24072, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xd7c1), ack 1641, win 371, options [nop,nop,TS val 7880905 ecr 7880904], length 0
06:59:41.998380 IP (tos 0x0, ttl 64, id 24073, offset 0, flags [DF], proto TCP (6), length 405)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc81a), seq 1908:2261, ack 1641, win 371, options [nop,nop,TS val 7881118 ecr 7880904], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236781, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:41", "ip-address": "172.18.0.108", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:42.008824 IP (tos 0x0, ttl 64, id 6829, offset 0, flags [DF], proto TCP (6), length 208)
    kea_2.kea-mng.http-alt > 085fd121c5c6.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x088f), seq 1641:1797, ack 2261, win 269, options [nop,nop,TS val 7881119 ecr 7881118], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:42 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:42.008877 IP (tos 0x0, ttl 64, id 24074, offset 0, flags [DF], proto TCP (6), length 52)
    085fd121c5c6.44216 > kea_2.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xd40f), ack 1797, win 379, options [nop,nop,TS val 7881119 ecr 7881119], length 0
06:59:45.015705 IP (tos 0x0, ttl 64, id 5439, offset 0, flags [DF], proto TCP (6), length 176)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x80fc), seq 1784:1908, ack 1387, win 371, options [nop,nop,TS val 7881420 ecr 7880250], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:45.022784 IP (tos 0x0, ttl 64, id 182, offset 0, flags [DF], proto TCP (6), length 306)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x594e (incorrect -> 0xeeba), seq 1387:1641, ack 1908, win 260, options [nop,nop,TS val 7881420 ecr 7881420], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:45 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:45 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:45.022912 IP (tos 0x0, ttl 64, id 5440, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0450), ack 1641, win 379, options [nop,nop,TS val 7881420 ecr 7881420], length 0
06:59:46.089643 IP (tos 0x0, ttl 64, id 5441, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xee12), seq 1908:2261, ack 1641, win 379, options [nop,nop,TS val 7881527 ecr 7881420], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236786, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:42", "ip-address": "172.18.0.109", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:46.100810 IP (tos 0x0, ttl 64, id 183, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x35f6), seq 1641:1797, ack 2261, win 269, options [nop,nop,TS val 7881528 ecr 7881527], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:46 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:46.101035 IP (tos 0x0, ttl 64, id 5442, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0172), ack 1797, win 388, options [nop,nop,TS val 7881528 ecr 7881528], length 0
06:59:49.422866 IP (tos 0x0, ttl 64, id 5443, offset 0, flags [DF], proto TCP (6), length 405)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xef52), seq 2261:2614, ack 1797, win 388, options [nop,nop,TS val 7881860 ecr 7881528], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236789, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:43", "ip-address": "172.18.0.110", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:49.430796 IP (tos 0x0, ttl 64, id 184, offset 0, flags [DF], proto TCP (6), length 208)
    085fd121c5c6.http-alt > kea_2.kea-mng.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x3154), seq 1797:1953, ack 2614, win 277, options [nop,nop,TS val 7881861 ecr 7881860], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:49 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:49.430907 IP (tos 0x0, ttl 64, id 5444, offset 0, flags [DF], proto TCP (6), length 52)
    kea_2.kea-mng.47044 > 085fd121c5c6.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xfcd2), ack 1953, win 396, options [nop,nop,TS val 7881861 ecr 7881861], length 0

## kea_2

06:59:13.558062 IP (tos 0x0, ttl 64, id 5427, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x1fc4), seq 124:477, ack 255, win 321, options [nop,nop,TS val 7878270 ecr 7878004], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236753, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:33", "ip-address": "172.18.0.100", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:13.568183 IP (tos 0x0, ttl 64, id 176, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x5eef), seq 255:411, ack 477, win 235, options [nop,nop,TS val 7878271 ecr 7878270], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:13 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:13.568211 IP (tos 0x0, ttl 64, id 5428, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x2781), ack 411, win 329, options [nop,nop,TS val 7878271 ecr 7878271], length 0
06:59:17.049679 IP (tos 0x0, ttl 64, id 24059, offset 0, flags [DF], proto TCP (6), length 176)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x7191), seq 124:248, ack 255, win 312, options [nop,nop,TS val 7878620 ecr 7877403], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:17.053316 IP (tos 0x0, ttl 64, id 6822, offset 0, flags [DF], proto TCP (6), length 306)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x594e (incorrect -> 0xdb0c), seq 255:509, ack 248, win 227, options [nop,nop,TS val 7878620 ecr 7878620], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:17 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:17 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:17.053384 IP (tos 0x0, ttl 64, id 24060, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xf4b4), ack 509, win 321, options [nop,nop,TS val 7878620 ecr 7878620], length 0
06:59:18.874376 IP (tos 0x0, ttl 64, id 24061, offset 0, flags [DF], proto TCP (6), length 405)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xe230), seq 248:601, ack 509, win 321, options [nop,nop,TS val 7878802 ecr 7878620], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236758, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:34", "ip-address": "172.18.0.101", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:18.877454 IP (tos 0x0, ttl 64, id 6823, offset 0, flags [DF], proto TCP (6), length 208)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x28ac), seq 509:665, ack 601, win 235, options [nop,nop,TS val 7878802 ecr 7878802], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:18 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:18.877877 IP (tos 0x0, ttl 64, id 24062, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xf143), ack 665, win 329, options [nop,nop,TS val 7878802 ecr 7878802], length 0
06:59:22.561932 IP (tos 0x0, ttl 64, id 5429, offset 0, flags [DF], proto TCP (6), length 176)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x9a95), seq 477:601, ack 411, win 329, options [nop,nop,TS val 7879171 ecr 7878271], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:22.563444 IP (tos 0x0, ttl 64, id 177, offset 0, flags [DF], proto TCP (6), length 306)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x594e (incorrect -> 0x0f55), seq 411:665, ack 601, win 235, options [nop,nop,TS val 7879171 ecr 7879171], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:22 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:22 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:22.563492 IP (tos 0x0, ttl 64, id 5430, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x1ef7), ack 665, win 337, options [nop,nop,TS val 7879171 ecr 7879171], length 0
06:59:22.574582 IP (tos 0x0, ttl 64, id 5431, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x1127), seq 601:954, ack 665, win 337, options [nop,nop,TS val 7879172 ecr 7879171], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236762, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:35", "ip-address": "172.18.0.102", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:22.584353 IP (tos 0x0, ttl 64, id 178, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x5365), seq 665:821, ack 954, win 243, options [nop,nop,TS val 7879173 ecr 7879172], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:22 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:22.628326 IP (tos 0x0, ttl 64, id 5432, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x1ce8), ack 821, win 346, options [nop,nop,TS val 7879178 ecr 7879173], length 0
06:59:26.274675 IP (tos 0x0, ttl 64, id 5433, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0x07ad), seq 954:1307, ack 821, win 346, options [nop,nop,TS val 7879542 ecr 7879173], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236766, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:36", "ip-address": "172.18.0.103", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:26.327969 IP (tos 0x0, ttl 64, id 179, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x4e73), seq 821:977, ack 1307, win 252, options [nop,nop,TS val 7879547 ecr 7879542], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:26 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:26.328020 IP (tos 0x0, ttl 64, id 5434, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x17fc), ack 977, win 354, options [nop,nop,TS val 7879547 ecr 7879547], length 0
06:59:28.296804 IP (tos 0x0, ttl 64, id 24063, offset 0, flags [DF], proto TCP (6), length 176)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x642a), seq 601:725, ack 665, win 329, options [nop,nop,TS val 7879748 ecr 7878802], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:28.298553 IP (tos 0x0, ttl 64, id 6824, offset 0, flags [DF], proto TCP (6), length 306)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x594e (incorrect -> 0xccbb), seq 665:919, ack 725, win 235, options [nop,nop,TS val 7879748 ecr 7879748], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:28 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:28 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:28.298689 IP (tos 0x0, ttl 64, id 24064, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xe85d), ack 919, win 337, options [nop,nop,TS val 7879748 ecr 7879748], length 0
06:59:29.229138 IP (tos 0x0, ttl 64, id 5435, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xfe06), seq 1307:1660, ack 977, win 354, options [nop,nop,TS val 7879841 ecr 7879547], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236769, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:37", "ip-address": "172.18.0.104", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:29.230883 IP (tos 0x0, ttl 64, id 180, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x4a1a), seq 977:1133, ack 1660, win 260, options [nop,nop,TS val 7879841 ecr 7879841], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:29 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:29.230912 IP (tos 0x0, ttl 64, id 5436, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x13aa), ack 1133, win 363, options [nop,nop,TS val 7879841 ecr 7879841], length 0
06:59:32.314326 IP (tos 0x0, ttl 64, id 24065, offset 0, flags [DF], proto TCP (6), length 405)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xd2fc), seq 725:1078, ack 919, win 337, options [nop,nop,TS val 7880149 ecr 7879748], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236772, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:38", "ip-address": "172.18.0.105", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:32.317838 IP (tos 0x0, ttl 64, id 6825, offset 0, flags [DF], proto TCP (6), length 208)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x18ac), seq 919:1075, ack 1078, win 243, options [nop,nop,TS val 7880150 ecr 7880149], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:32 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:32.317988 IP (tos 0x0, ttl 64, id 24066, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xe333), ack 1075, win 346, options [nop,nop,TS val 7880150 ecr 7880150], length 0
06:59:33.319178 IP (tos 0x0, ttl 64, id 5437, offset 0, flags [DF], proto TCP (6), length 176)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x88a9), seq 1660:1784, ack 1133, win 363, options [nop,nop,TS val 7880250 ecr 7879841], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:33.322475 IP (tos 0x0, ttl 64, id 181, offset 0, flags [DF], proto TCP (6), length 306)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x594e (incorrect -> 0xfd5a), seq 1133:1387, ack 1784, win 260, options [nop,nop,TS val 7880250 ecr 7880250], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:33 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:33 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:33.322526 IP (tos 0x0, ttl 64, id 5438, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0ef6), ack 1387, win 371, options [nop,nop,TS val 7880250 ecr 7880250], length 0
06:59:35.557433 IP (tos 0x0, ttl 64, id 24067, offset 0, flags [DF], proto TCP (6), length 405)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc91f), seq 1078:1431, ack 1075, win 346, options [nop,nop,TS val 7880474 ecr 7880150], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236775, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:39", "ip-address": "172.18.0.106", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:35.558987 IP (tos 0x0, ttl 64, id 6826, offset 0, flags [DF], proto TCP (6), length 208)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x141a), seq 1075:1231, ack 1431, win 252, options [nop,nop,TS val 7880474 ecr 7880474], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:35 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:35.559082 IP (tos 0x0, ttl 64, id 24068, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xdea6), ack 1231, win 354, options [nop,nop,TS val 7880474 ecr 7880474], length 0
06:59:38.859100 IP (tos 0x0, ttl 64, id 24069, offset 0, flags [DF], proto TCP (6), length 405)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc98b), seq 1431:1784, ack 1231, win 354, options [nop,nop,TS val 7880804 ecr 7880474], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236778, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:40", "ip-address": "172.18.0.107", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:38.861043 IP (tos 0x0, ttl 64, id 6827, offset 0, flags [DF], proto TCP (6), length 208)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x0f7e), seq 1231:1387, ack 1784, win 260, options [nop,nop,TS val 7880804 ecr 7880804], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:38 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:38.861141 IP (tos 0x0, ttl 64, id 24070, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xda0c), ack 1387, win 363, options [nop,nop,TS val 7880804 ecr 7880804], length 0
06:59:39.860249 IP (tos 0x0, ttl 64, id 24071, offset 0, flags [DF], proto TCP (6), length 176)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x5041), seq 1784:1908, ack 1387, win 363, options [nop,nop,TS val 7880904 ecr 7880804], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:39.864068 IP (tos 0x0, ttl 64, id 6828, offset 0, flags [DF], proto TCP (6), length 306)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x594e (incorrect -> 0xba27), seq 1387:1641, ack 1908, win 260, options [nop,nop,TS val 7880904 ecr 7880904], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:39 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:39 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:39.864299 IP (tos 0x0, ttl 64, id 24072, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xd7c1), ack 1641, win 371, options [nop,nop,TS val 7880905 ecr 7880904], length 0
06:59:41.998412 IP (tos 0x0, ttl 64, id 24073, offset 0, flags [DF], proto TCP (6), length 405)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xc81a), seq 1908:2261, ack 1641, win 371, options [nop,nop,TS val 7881118 ecr 7880904], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236781, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:41", "ip-address": "172.18.0.108", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:42.008785 IP (tos 0x0, ttl 64, id 6829, offset 0, flags [DF], proto TCP (6), length 208)
    05e1a4a4476e.http-alt > kea_1.kea-mng.44216: Flags [P.], cksum 0x58ec (incorrect -> 0x088f), seq 1641:1797, ack 2261, win 269, options [nop,nop,TS val 7881119 ecr 7881118], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:42 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:42.008894 IP (tos 0x0, ttl 64, id 24074, offset 0, flags [DF], proto TCP (6), length 52)
    kea_1.kea-mng.44216 > 05e1a4a4476e.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0xd40f), ack 1797, win 379, options [nop,nop,TS val 7881119 ecr 7881119], length 0
06:59:45.015655 IP (tos 0x0, ttl 64, id 5439, offset 0, flags [DF], proto TCP (6), length 176)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x58cc (incorrect -> 0x80fc), seq 1784:1908, ack 1387, win 371, options [nop,nop,TS val 7881420 ecr 7880250], length 124: HTTP, length: 124
  POST / HTTP/1.1
  Content-Length: 53
  Content-Type: application/json

  { "command": "ha-heartbeat", "service": [ "dhcp4" ] }[!http]
06:59:45.022860 IP (tos 0x0, ttl 64, id 182, offset 0, flags [DF], proto TCP (6), length 306)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x594e (incorrect -> 0xeeba), seq 1387:1641, ack 1908, win 260, options [nop,nop,TS val 7881420 ecr 7881420], length 254: HTTP, length: 254
  HTTP/1.1 200 OK
  Content-Length: 145
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:45 GMT

  [ { "arguments": { "date-time": "Wed, 20 Nov 2019 06:59:45 GMT", "state": "load-balancing" }, "result": 0, "text": "HA peer status returned." } ][!http]
06:59:45.022897 IP (tos 0x0, ttl 64, id 5440, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0450), ack 1641, win 379, options [nop,nop,TS val 7881420 ecr 7881420], length 0
06:59:46.089589 IP (tos 0x0, ttl 64, id 5441, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xee12), seq 1908:2261, ack 1641, win 379, options [nop,nop,TS val 7881527 ecr 7881420], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236786, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:42", "ip-address": "172.18.0.109", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:46.100884 IP (tos 0x0, ttl 64, id 183, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x35f6), seq 1641:1797, ack 2261, win 269, options [nop,nop,TS val 7881528 ecr 7881527], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:46 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]
06:59:46.100966 IP (tos 0x0, ttl 64, id 5442, offset 0, flags [DF], proto TCP (6), length 52)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [.], cksum 0x5850 (incorrect -> 0x0172), ack 1797, win 388, options [nop,nop,TS val 7881528 ecr 7881528], length 0
06:59:49.422817 IP (tos 0x0, ttl 64, id 5443, offset 0, flags [DF], proto TCP (6), length 405)
    05e1a4a4476e.47044 > kea_1.kea-mng.http-alt: Flags [P.], cksum 0x59b1 (incorrect -> 0xef52), seq 2261:2614, ack 1797, win 388, options [nop,nop,TS val 7881860 ecr 7881528], length 353: HTTP, length: 353
  POST / HTTP/1.1
  Content-Length: 281
  Content-Type: application/json

  { "arguments": { "expire": 1574236789, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "00:00:00:11:22:43", "ip-address": "172.18.0.110", "state": 0, "subnet-id": 1, "valid-lft": 3600 }, "command": "lease4-update", "service": [ "dhcp4" ] }[!http]
06:59:49.430854 IP (tos 0x0, ttl 64, id 184, offset 0, flags [DF], proto TCP (6), length 208)
    kea_1.kea-mng.http-alt > 05e1a4a4476e.47044: Flags [P.], cksum 0x58ec (incorrect -> 0x3154), seq 1797:1953, ack 2614, win 277, options [nop,nop,TS val 7881861 ecr 7881860], length 156: HTTP, length: 156
  HTTP/1.1 200 OK
  Content-Length: 48
  Content-Type: application/json
  Date: Wed, 20 Nov 2019 06:59:49 GMT

  [ { "result": 0, "text": "IPv4 lease added." } ][!http]

上記より，kea_1とkea_2との間で双方向にリースアップデートを更新していることがことがわかる． load-balancingモードの場合は，hot-standbyモードとは異なり，リースしたサーバからそうでないサーバ（群）に対してリースアップデートを行うため，リースアップデートが一方向のみでなく，双方向に行われる違いがある． これがパフォーマンス低下の原因となるため，一般にhot-standbyモードよりもload-balancingモードの方が応答が遅くなる傾向があるようである．

• ref: Kea Performance Optimization section 7の Consider the impact of high availability に

  Active-Passive is more efficient than load-balancing. をはじめとし，load-balancingモードとhot-standbyモードでのパフォーマンスの違いの解説が書かれている．

まとめ

Kea DHCPを使ってload-balancingモードのHA構成を組むことができました． 本記事では以下のことを実施しました．

• ISCのKea DHCPを用いてload-balancingモードのHA構成を組むことについて紹介した．
• load-balancingモードのHAにおいて実際にクライアントを模擬してDHCPによるアドレスリースを行い，hot-standbyモードと比べたの応答の違いをパケットキャプチャによって確認した．

次回以降では，RFC3074の掘り下げ，HA構成を取ることによるパフォーマンス影響，HA構成で本当に冗長化ができているのか，等について見てみようと考えています．

References

• Kea DHCPのHigh-Availabilityを検証する - (1)Act-Sbyのhot-standby構成を組む - JP7FKFの備忘録
• Internet Systems Consortium - Kea
• Kea Documentation
• Kea Performance Optimization
• Kea High Availability vs ISC DHCP Failover - Kea DHCP
• RFC3074
• DHCP Failover Load Balance Mode – Microsoft Windows DNS, DHCP and IPAM Team Blog

P.S.

• 例によってQiitaに投稿してみました
  • Kea DHCPでAct-Act(load-balancing)のHA構成を組む - Qiita