custom-config/rt-mep/kea-dhcp4.conf

// /etc/kea/kea-dhcp4.conf
// sudo systemctl restart kea-dhcp4-server
{
"Dhcp4": {
    "interfaces-config": {
        "interfaces": [ "eth1/10.100.2.1" ]
        // "dhcp-socket-type": "udp"
    },

    "control-socket": {
        "socket-type": "unix",
        "socket-name": "/tmp/kea4-ctrl-socket"
    },

    "lease-database": {
        // Memfile is the simplest and easiest backend to use. It's an in-memory
        // C++ database that stores its state in CSV file.
        "type": "memfile",
        "lfc-interval": 3600
    },

    "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": 900,
    "rebind-timer": 1800,
    "valid-lifetime": 3600,

    "option-data": [
        {
            "name": "domain-name-servers",
            "data": "10.100.2.1, 1.1.1.1"
        },

        // "name": "domain-name" or "code": 15.
        {
            "code": 15,
            "data": "enpls.org"
        },

        {
            "name": "domain-search",
            "data": "nl.x9.pm"
        }
    ],

    "subnet4": [
        {
            "subnet": "10.100.2.0/24",
            "pools": [ { "pool": "10.100.2.100 - 10.100.2.200" } ],
            "option-data": [
                {
                    "name": "routers",
                    "data": "10.100.2.1"
                }
            ],

            // Kea offers host reservations mechanism. Kea supports reservations
            // by several different types of identifiers: hw-address
            // (hardware/MAC address of the client), duid (DUID inserted by the
            // client), client-id (client identifier inserted by the client) and
            // circuit-id (circuit identifier inserted by the relay agent).
            //
            // Kea also support flexible identifier (flex-id), which lets you
            // specify an expression that is evaluated for each incoming packet.
            // Resulting value is then used for as an identifier.
            //
            // Note that reservations are subnet-specific in Kea. This is
            // different than ISC DHCP. Keep that in mind when migrating
            // your configurations.
            "reservations": [
                // You can add more reservations here.
            ]
            // You can add more subnets there.
        }
    ],

    // There are many, many more parameters that DHCPv4 server is able to use.
    // They were not added here to not overwhelm people with too much
    // information at once.

    // Logging configuration starts here. Kea uses different loggers to log various
    // activities. For details (e.g. names of loggers), see Chapter 18.
    "loggers": [
    {
        // This section affects kea-dhcp4, which is the base logger for DHCPv4
        // component. It tells DHCPv4 server to write all log messages (on
        // severity INFO or more) to a file.
        "name": "kea-dhcp4",
        "output_options": [
            {
                // Specifies the output file. There are several special values
                // supported:
                // - stdout (prints on standard output)
                // - stderr (prints on standard error)
                // - syslog (logs to syslog)
                // - syslog:name (logs to syslog using specified name)
                // Any other value is considered a name of the file
                "output": "/var/log/kea-dhcp4.log"

                // Shorter log pattern suitable for use with systemd,
                // avoids redundant information
                // "pattern": "%-5p %m\n"

                // This governs whether the log output is flushed to disk after
                // every write.
                // "flush": false,

                // This specifies the maximum size of the file before it is
                // rotated.
                // "maxsize": 1048576,

                // This specifies the maximum number of rotated files to keep.
                // "maxver": 8
            }
        ],
        // This specifies the severity of log messages to keep. Supported values
        // are: FATAL, ERROR, WARN, INFO, DEBUG
        "severity": "INFO",

        // If DEBUG level is specified, this value is used. 0 is least verbose,
        // 99 is most verbose. Be cautious, Kea can generate lots and lots
        // of logs if told to do so.
        "debuglevel": 0
    }
  ]
}
}