Since mid 2023 I have been running a Docker ISC Kea Image using base Docker Alpine Linux images, with S6 init system. (ISC Kea is a modern replacement for their DHCP.) The main DHCP server runs on my main server and I have an automatic fall over back up on my separate Linux router. I basically followed the Kea template Home Network of a Power User. I was never quite sure I had the automatic fall over back-up working. On 2023-01-02 I modified a configuration file on the primary server with a syntax error, 8 days later I notice millions of lines of errors on my log files. Sure enough the backup had simply been working. I fixed up the simple syntax error and the primary server took back over. Everything basically worked as expected.
ISC also has a project for a simple GUI interface primarily for Kea and basic for Bind9. There is apparently no Alpine package yet for Stork.
ISC-Kea seems to be provided in a number of packages
| Package | Descriptiion | Comment |
|---|---|---|
| isc-kea-admin | This package provides backend database initialization and migration scripts and a DHCP benchmark tool. If you are not using a database backend, you may not need this. | Not using a database backend at this time |
| isc-kea-common | Common libraries for the ISC Kea DHCP server. Install this. | Need this. |
| isc-kea-ctrl-agent | This package provides the REST API service agent for Kea DHCP. | ? |
| isc-kea-dev | Development headers for ISC Kea DHCP server. Install if you plan to create any custom Kea hooks. | Probably do not need. |
| isc-kea-dhcp4-server | DHCPv4 server. | Need this. |
| isc-kea-dhcp6-server | DHCPv6 server. | Do not need at this time. |
| isc-kea-dhcp-ddns-server | DDNS server. | Need this. |
| isc-kea-doc | Kea documentation. Highly recommended. | On a Docker container? |
| isc-kea-hook-flex-option | Flexible Options hook. | What is this? |
| isc-kea-hook-ha | High Availability hook. | What is this? |
| isc-kea-hook-lease-cmds | Lease Commands hook. | What is this? |
| isc-kea-hook-mysql-cb | MySQL Configuration Backend. | Dont need this at this time. |
| isc-kea-hook-pgsql-cb | PostgreSQL Configuration Backend. | Dont need this. |
| isc-kea-hook-stat-cmds | Statistics Commands hook. | ? |
| isc-kea-http | This package is essential, install it. | It is essential… |
| isc-kea-perfdhcp | Optional. Includes a DHCP performance testing tool from ISC. | ? |
| isc-kea-shell | Text client for Kea DHCP Control Agent. | ? |
From IANA Service Name and Transport Protocol Port online Number Registry:
bootps 67 {tcp, udp} Bootstrap Protocol Server (DHCP)
bootpc 68 {tcp, udp} Bootstrap Protocol Client (DHCP)
The Kea Control Agent uses port 8000 by default, but that value can be manually defined in its configuration file. (Usually located at /etc/kea/kea-ctrl-agent.conf.) This port needs to be open and accessible on every server that hosts a Kea DHCP service and a Kea Control Agent.
This is a good case where the Docker network type needs to be set to host. The DHCP server needs to be directly on the host to function.
sudo nmap --script broadcast-dhcp-discover will test for DHCP servers on the same network. It will only report the first DHCP server discovered.
kea-dhcp4 -t /app/dhcpv4.conf to test the kea-dhcp4 configuration files /app/dhcpv4.confkea-dhcp4 -c /app/dhcpv4.conf to start kea dhcp4 using configuration file /app/dhcpv4.confkea-dhcp4 -c /app/dhcpv4_plus.conf to start kea dhcp4 using configuration file /app/dhcpv4_plus.conf. This configuration file is designed to work with the kea control agent setup. Where as the basic configuration /app/dhcpv4_basic.conf is not.kea-ctrl-agent -t /app/kea-ctrl-agent.conf to test the kea-cont-agent configuration file /app/kea-ctrl-agent.conf kea-ctrl-agent -c /app/kea-ctrl-agent.conf to start the kea-cont-agent configuration file /app/kea-ctrl-agent.confI have stored log files in the .config directory that is a Docker mounted volume for persistence and easy external viewing outside container. The following logs files can be seen.
.config/log/kea-dhcp4-commands.log.config/log/kea-dhcp4-dhcpsrv.log.config/log/kea-dhcp4-leases.log.config/log/kea-dhcp4.log.config/log/kea-dhcp4-ha-hooks.logdocker attach kptr-kea-1 to attach to running containerkea-dhcp4 -v To check running version