Kea DHCP

Control

Get DHCP4 Server Status

 keactrl status -s dhcp4

Reload DHCP4 Server

You'll want to do this after making changes to the kea-dhcp4.conf file.

 keactrl reload -s dhcp4

Leases

Leases are stored in memfile, by default. But you can also have them written to a CSV file:

 "lease-database": {
     "type": "memfile", // write leases to memfile...
     "persist": true,
     "name": "/tmp/kea-leases4.csv", // ...but also write them to csv
     "lfc-interval": 3600,
     "max-row-errors": 100
 },

MySQL

To use host reservations from MySQL, you need to add the "hosts-database" section to the "Dhcp4" section of the config file, like this:

 "hosts-database": {
     "type": "mysql",
     "name": "kea_db",
     "user": "kea-user",
     "password": "super-secret-password",
     "host": "localhost",
     "port": 3306
 },

Subnet-Ids need to be defined in your subnet declarations, too.

You can use both the hosts database and the configuration file for host reservations at the same time.

IPv4 Reservations

Insert Statement Example:

 SELECT host_id,dhcp_identifier,dhcp4_subnet_id,ipv4_address,hostname FROM hosts;
 
 START TRANSACTION;
 SET @ipv4_reservation='10.1.70.11';
 SET @hostname = 'windows-pc';
 SET @identifier_type='hw-address';
 SET @identifier_value='be:ef:be:ef:be:ef';
 SET @dhcp4_subnet_id=70;
 
 INSERT INTO hosts (dhcp_identifier,
                    dhcp_identifier_type,
                    dhcp4_subnet_id,
                    ipv4_address,
                    hostname)
 VALUES (UNHEX(REPLACE(@identifier_value, ':', )),
 	(SELECT type FROM host_identifier_type WHERE name=@identifier_type),
         @dhcp4_subnet_id,
         INET_ATON(@ipv4_reservation),
         @hostname);
 
 COMMIT;

Manual Dump of Host Reservations

 mysqldump -u kea-user -p kea_db hosts > kea-hosts.sql

Sync db From Primary to Standby Peers

Follow the steps below to configure a Standby peer to sync its hosts db from the Primary peer.

Crontab for use on Standby peers

Use this crontab to automatically sync a Standby peer with the Primary peer's kea_db.hosts table (i.e., push from Primary to Standby).

 mysqldump -h net1.lambnet.us -u kea-xfer -p{password} --single-transaction --no-tablespaces kea_db hosts | mysql -u kea-xfer -p{password} kea_db

...

MySQL Performance Tuning

Configure in /etc/mysql/my.cnf:

[mysqld]
innodb_flush_log_at_trx_commit=2

SystemD Tip

You may encounter an issue where kea-dhcp4 fails to start at boot. Try adding this to /usr/lib/systemd/system/kea-dhcp4.service, at the end of the [Unit] section:

 After=mysqld.service

Kea-Shell

Commands

[ { "arguments": [ "build-report", "config-backend-pull", "config-get", "config-reload", "config-set", "config-test", "config-write", "dhcp-disable", "dhcp-enable", "ha-continue", "ha-heartbeat", "ha-maintenance-cancel", "ha-maintenance-notify", "ha-maintenance-start", "ha-reset", "ha-scopes", "ha-sync", "ha-sync-complete-notify", "lease4-add", "lease4-del", "lease4-get", "lease4-get-all", "lease4-get-by-client-id", "lease4-get-by-hostname", "lease4-get-by-hw-address", "lease4-get-page", "lease4-resend-ddns", "lease4-update", "lease4-wipe", "lease6-add", "lease6-bulk-apply", "lease6-del", "lease6-get", "lease6-get-all", "lease6-get-by-duid", "lease6-get-by-hostname", "lease6-get-page", "lease6-resend-ddns", "lease6-update", "lease6-wipe", "leases-reclaim", "libreload", "list-commands", "server-tag-get", "shutdown", "statistic-get", "statistic-get-all", "statistic-remove", "statistic-remove-all", "statistic-reset", "statistic-reset-all", "statistic-sample-age-set", "statistic-sample-age-set-all", "statistic-sample-count-set", "statistic-sample-count-set-all", "status-get", "version-get" ], "result": 0 } ]

Get Status

 kea-shell --host 10.144.30.8 --service dhcp4 status-get

Links

ISC-Kea

https://kea.readthedocs.io/en/latest/arm/config.html

Stork

https://stork.readthedocs.io/en/v1.8.0/

https://gitlab.isc.org/isc-projects/stork/-/wikis/Screenshots