Kea
Kea is a DHCP server developed by the Internet Systems Consortium. It is a newer (next generation) DHCP server from the same authors of ISC DHCP
Installation
USE flags
USE flags for net-misc/kea High-performance production grade DHCPv4 & DHCPv6 server
debug
|
Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces |
doc
|
Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally |
filecaps
|
Use Linux file capabilities to control privilege rather than set*id (this is orthogonal to USE=caps which uses capabilities at runtime e.g. libcap) |
mysql
|
Add mySQL Database support |
openssl
|
Use dev-libs/openssl instead of dev-libs/botan |
postgres
|
Add support for the postgresql database |
samples
|
Install sample configuration files |
shell
|
Install kea-shell text management client for Control Agent |
test
|
Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently) |
Emerge
root #emerge --ask net-misc/keaConfiguration
OpenRC only
After installing, the default configuration files are found in /etc/kea and are prefixed with kea, e.g. kea_dhcp4.conf.
If using OpenRC, these need to be renamed to match that used in the /etc/conf.d/kea daemon config, for example:
root #cp /etc/kea/kea_dhcp4.conf /etc/kea/dhcp4.confTo use the high availability feature of Kea, the kea-ctrl-agent must be started to allow the primary & standby server(s) to communicate. Currently the OpenRC scripts do not contain the starting of the Kea-ctrl-agent and so need to be modified.
Edit the /etc/init.d/kea script and in each section add additional code for the agent. For example in the start() section, add the following:
/etc/init.d/kea...
if ${AGENT:-false} ; then
start-stop-daemon -m -b -p ${agent_pidfile} \
-s ${agent_command} -- -c ${agent_config} \
|| return 1
fi
...
AGENT needs to be defined in /etc/conf.d/kea.
The agent_pidfile, agent_command and agent_config need to be defined at the top, like so:
/etc/init.d/kea...
agent_command="/usr/sbin/kea-ctrl-agent"
agent_config="${AGENT_CONFIG:-/etc/kea/ctrl-agent.conf}"
agent_pidfile="/run/kea-ctrl-agent.pid"
Note: PID files are created by Kea with a filename that embeds the config used. The installed /etc/init.d/kea tells start-stop-daemon to also create pid files with a different path. This works, but can be confusing to see 2 PID files for the same process. It is possible to remove the '-m' option from start-stop-daemon call and specify in the '-p' option the PID filepath that the kea processes create.
So that kea is started after the network is up and for example; the network interface is eth0; add to /etc/conf.d/kea the following:
/etc/conf.d/kea... rc_need="net.eth0 logger" ...
It is useful to require a logger, so any crash detected by start-stop-daemon is logged.
Files
OpenRC
For OpenRC, the file paths are defined in /etc/conf.d/kea and /etc/init.d/kea, they can be modified if required.
- /etc/kea/dhcp4.conf - Configuration for the kea-dhcp4 daemon
- /etc/kea/dhcp6.conf - Configuration for the kea-dhcp6 daemon
- /etc/kea/ddns.conf - Configuration for the kea-ddns daemon
If the modification to the daemon scripts have been performed, the following addition config is available:
- /etc/kea/ctrl-agent.conf - Configuration for the kea-ctrl-agent daemon
Systemd
For Systemd the file paths are the paths as defined in the unit files in /lib/systemd/system/kea*.
- /etc/kea/kea-dhcp4.conf - Configuration for the kea-dhcp4 daemon
- /etc/kea/kea-dhcp6.conf - Configuration for the kea-dhcp6 daemon
- /etc/kea/kea-ddns.conf - Configuration for the kea-ddns daemon
- /etc/kea/kea-ctrl-agent.conf - Configuration for the kea-ctrl-agent daemon
Service
OpenRC
root #rc-update add kea
root #rc-service kea start
Runnng as non-root
By default Kea runs as root as it requires access to priviledged ports.
To avoid running as root, first install acct-user/dhcp (if not already installed). This creates a user and group called dhcp.
The binaries need capabilities added so they can access the priviledged ports and raw sockets.
root #setcap 'cap_net_bind_service,cap_net_raw=+ep' /usr/sbin/kea-dhcp4root #setcap 'cap_net_bind_service=+ep' /usr/sbin/kea-dhcp6If using OpenRC, the kea ini script needs to be modified so the option --u dhcp is passed as an additional argument to start-stop-daemon.
Check all kea config files are accessible via the dhcp user.
Set kea log & database files in /var to be owned by dhcp, or at least writable by kea.
Usage
Hook Libraries
Run Script Support
Kea has a useful interface to run scripts on certain events. For example this can be used to update DNS records when leases are allocated or revoked.
Removal
Unmerge
root #emerge --ask --depclean --verbose net-misc/kea