Removing netplan from Ubuntu

For the last year or more I have been confused by a problem where LXC containers get two IP addresses assigned.

Naturally you want static IPs for server containers defined in lxc/$name/config

lxc.net.0.ipv4.address = 10.0.3.2/24
lxc.net.0.ipv4.gateway = 10.0.3.1

would get two ip addresses on boot, the statically assigned one by lxc and another randomly assigned one.

I never really understood the root cause.

I fixed this by disabling files here and there, removing ip config from lxc/$name/config, and then and in /etc/rc.local running ip addr add 10.0.3.2/24 scope global dev eth0
ip route add default via 10.0.3.1 dev eth0

Some of my containers use Ubuntu, most use lxinitd, I did not notice that the problem was limited to Ubuntu.

The above solution requires installing iproute2 i.e. /sbin/ip in containers, which in tern, requires mounting /lib lib64 /usr/lib and not being able to run a fully statically compiled container.

This fella has a much simpler solution

https://www.claudiokuenzler.com/blog/938/lxc-container-not-getting-ip-address-netplan

Netplan is root cause of the problem, and it can be removed.

apt-get remove netplan.io

Now setting the IP address in lxc/$name/config works across all my containers.