kea/doc/examples/kea4/ha-load-balancing-server2-mt.json

// This is an example configuration of the Kea DHCPv4 server. It uses High
// Availability hook library and Lease Commands hook library to enable
// High Availability function for the DHCP server. Note that almost exactly
// the same configuration must be used on the second server (partner).
// The only difference is that "this-server-name" must be set to "server1"
// on this other server. Also, the interface configuration depends on the
// network settings of the particular machine.
//
// The servers using this configuration work in load balancing mode.
{

// DHCPv4 configuration starts here.
"Dhcp4": {
    // Add names of your network interfaces to listen on.
    "interfaces-config": {
        // The DHCPv4 server listens on this interface.
        "interfaces": [ "eth0" ]
    },

    // Control socket is required for communication between the Control
    // Agent and the DHCP server. High Availability with MT does not require
    // Control Agent to be running because lease updates are sent over the
    // RESTful API between the HA peers using the server dedicated listener.
    // The Control Agent is used only to handle user commands.
    "control-socket": {
        "socket-type": "unix",
        "socket-name": "kea4-ctrl-socket"
    },

    // Multi-threading parameters.
    "multi-threading": {
        // By default, Kea processes packets on multiple threads if the hardware permits.
        "enable-multi-threading": true,

        // When multi-threading is enabled, Kea will process packets on a
        // number of multiple threads configurable through this option.
        "thread-pool-size": 4,

        // When multi-threading is enabled, Kea will read packets from the
        // interface and append a working item to the thread pool. This
        // option configures the maximum number of items that can be queued.
        "packet-queue-size": 64
    },

    // Use Memfile lease database backend to store leases in a CSV file.
    // Depending on how Kea was compiled, it may also support SQL databases
    // (MySQL and/or PostgreSQL). Those database backends require more
    // parameters, like name, host and possibly user and password.
    // There are dedicated examples for each backend. See Section 7.2.2 "Lease
    // Storage" for details.
    "lease-database": {
        // Memfile is the simplest and easiest backend to use. It's an in-memory
        "type": "memfile"
    },

    // Client classes will associate address pools with certain servers taking
    // part in providing High Availability.
    "client-classes": [
        // phones class
        {
            "name": "phones",
            "test": "substring(option[60].hex,0,6) == 'Aastra'"
        },
        // laptops are everything but phones.
        {
            "name": "laptops",
            "test": "not member('phones')"
        },
        // Some phones will be handled by server1. Whether the HA_server1
        // or HA_server2 is assigned for the client is a matter of load
        // balancing performed by the HA hook library.
        {
            "name": "phones_server1",
            "test": "member('phones') and member('HA_server1')"
        },
        // Some phones will be handled by server2.
        {
            "name": "phones_server2",
            "test": "member('phones') and member('HA_server2')"
        },
        // Some laptops will be handled by server1.
        {
            "name": "laptops_server1",
            "test": "member('laptops') and member('HA_server1')"
        },
        // Some laptops will be handled by server2.
        {
            "name": "laptops_server2",
            "test": "member('laptops') and member('HA_server2')"
        }
    ],

    // HA requires two hook libraries to be loaded: libdhcp_lease_cmds.so and
    // libdhcp_ha.so. The former handles incoming lease updates from the HA peers.
    // The latter implements high availability feature for Kea.
    "hooks-libraries": [
        // The lease_cmds library must be loaded because HA makes use of it to
        // deliver lease updates to the server as well as synchronize the
        // lease database after failure.
        {
            "library": "/opt/lib/kea/hooks/libdhcp_lease_cmds.so",
            "parameters": { }
        },
        {
            // The HA hook library should be loaded.
            "library": "/opt/lib/kea/hooks/libdhcp_ha.so",
            "parameters": {
                // High Availability configuration is specified for the HA hook library.
                // Each server should have the same HA configuration, except for the
                // "this-server-name" parameter.
                "high-availability": [ {
                    // This parameter points to this server instance. The respective
                    // HA peers must have this parameter set to their own names.
                    "this-server-name": "server2",
                    // The HA mode is set to load-balancing. In this mode, the active
                    // servers share the traffic (50/50).
                    "mode": "load-balancing",
                    // Heartbeat is to be sent every 10 seconds if no other control
                    // commands are transmitted.
                    "heartbeat-delay": 10000,
                    // Maximum time for partner's response to a heartbeat, after which
                    // failure detection is started. This is specified in milliseconds.
                    "max-response-delay": 60000,
                    // The following parameters control how the server detects the
                    // partner's failure. The ACK delay sets the threshold for the
                    // 'secs' field of the received discovers. This is specified in
                    // milliseconds.
                    "max-ack-delay": 5000,
                    // This specifies the number of clients which send messages to
                    // the partner but appear to not receive any response.
                    "max-unacked-clients": 5,
                    // This specifies the maximum timeout (in milliseconds) for the server
                    // to complete sync. If you have a large deployment (high tens or
                    // hundreds of thausands of clients), you may need to increase it
                    // further. The default value is 60000ms (60 seconds).
                    "sync-timeout": 60000,
                    // To not experience performance degradation when the Kea server is
                    // processing packets on multiple threads, the High Availability module
                    // must have multi-threading enabled.
                    "multi-threading": {
                        // Enable High Availability to benefit from multi-threading. Default: true.
                        "enable-multi-threading": true,
                        // When running in MT mode, the dedicated listener is used to handle
                        // lease updates.
                        "http-dedicated-listener": true,
                        // The number of threads used to handle incoming requests.
                        // A value of 0 instructs the server to use the same number of
                        // threads that the Kea core is using for DHCP multi-threading.
                        "http-listener-threads": 0,
                        // The number of threads used to handle outgoing requests.
                        // A value of 0 instructs the server to use the same number of
                        // threads that the Kea core is using for DHCP multi-threading.
                        "http-client-threads": 0
                    },
                    "peers": [
                        // This is the configuration of the HA peer.
                        {
                            "name": "server1",
                            // Specifies the URL on which the partner's control
                            // channel can be reached. The Control Agent is not required
                            // to run on the partner's machine if multi-threading is enabled.
                            // The "http-host" and "http-port" values must be set to different
                            // values then the ones used by the Control Agent.
                            "url": "http://192.168.56.33:8000/",
                            // The partner is primary. This server is secondary.
                            "role": "primary"
                        },
                        // This is the configuration of this server instance.
                        {
                            "name": "server2",
                            // This specifies the URL of this server instance. The
                            // Control Agent is not required to run along with this DHCPv4 server
                            // instance if multi-threading is enabled.
                            // The "http-host" and "http-port" values must be set to different
                            // values then the ones used by the Control Agent.
                            "url": "http://192.168.56.66:8000/",
                            // This server is secondary. The other one must be
                            // primary.
                            "role": "secondary"
                        }
                    ]
                } ]
            }
        }
    ],

    // This example contains a single subnet declaration.
    "subnet4": [
        {
            // Subnet id.
            "id": 1,

            // Subnet prefix.
            "subnet": "192.0.3.0/24",

            // Specify four address pools.
            "pools": [
                {
                    "pool": "192.0.3.100 - 192.0.3.125",
                    "client-classes": [ "phones_server1" ]
                },
                {
                    "pool": "192.0.3.126 - 192.0.3.150",
                    "client-classes": [ "laptops_server1" ]
                },
                {
                    "pool": "192.0.3.200 - 192.0.3.225",
                    "client-classes": [ "phones_server2" ]
                },
                {
                    "pool": "192.0.3.226 - 192.0.3.250",
                    "client-classes": [ "laptops_server2" ]
                }
            ],

            // These are options that are subnet specific. In most cases,
            // you need to define at least routers option, as without this
            // option your clients will not be able to reach their default
            // gateway and will not have Internet connectivity.
            "option-data": [
                {
                    // For each IPv4 subnet you most likely need to specify at
                    // least one router.
                    "name": "routers",
                    "data": "192.0.3.1"
                }
            ],

            // This subnet will be selected for queries coming from the following
            // IP address.
            "relay": { "ip-addresses": [ "192.168.56.1" ] }
        }
    ],

// The following configures logging. It assumes that messages with at
// least informational level (info, warn, error and fatal) should be
// logged to stdout. Alternatively, you can specify stderr here, a filename
// or 'syslog', which will store output messages via syslog.
    "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": [
                {
                    "output": "stdout"
                }
            ],
            "severity": "INFO",
            "debuglevel": 0
        },
        {
            // This section specifies configuration of the HA hook library-specific
            // logger.
            "name": "kea-dhcp4.ha-hooks",
            "output-options": [
                {
                    "output": "stdout"
                }
            ],
            "severity": "INFO",
            "debuglevel": 99
        }
    ]
}
}