How to let built-in DHCP assign a static IP to LXC container based on name, not MAC address

I ran into this recently and I think I found an easy solution. I (only) tested it on Ubuntu 14.04.

First, uncomment this line /etc/default/lxc-net:

LXC_DHCP_CONFILE=/etc/lxc/dnsmasq.conf

In /etc/lxc/dnsmasq.conf, define a dhcp-hostsfile:

dhcp-hostsfile=/etc/lxc/dnsmasq-hosts.conf

Then add entries in /etc/lxc/dnsmasq-hosts.conf like this:

mail,10.0.3.16
web,10.0.3.17

Beware: changes will become effective after you have restarted lxc-net (which restarts dnsmasq):

service lxc-net restart

Afterwards you can modify /etc/lxc/dnsmasq-hosts.conf and send the SIGHUP signal to dnsmasq:

killall -s SIGHUP dnsmasq

So yes, you need to restart lxc-net, but only once. Hope this helps.

It works fine in Ubuntu 14.04.1

Uncomment this line /etc/default/lxc-net

#LXC_DHCP_CONFILE=/etc/lxc/dnsmasq.conf

stop all containers, restart lxc-net:

service lxc-net restart

Configure ip addresses in /etc/lxc/dnsmasq.conf

dhcp-host={NAME},10.0.3.2

where {NAME} is the name of your LXC container:

/var/lib/lxc/{NAME}

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