LXD public ip to container using routed

Question

I'm trying to set a public ip to a container using the routed nictype in LXD, Essentially i inited a fresh container, ran lxc config device add c1 eth0 nic nictype=routed parent=eth0 ipv4.address=my.public.ip then started the container, it shows the correct ip in the IPV4 section for a split second, and running an lxc list again shows it dissapearing into a blank. So it IS* being set properly, at least to lxc, but a few seconds after startup it goes away.

My guess is there's maybe some DHCP style nonsense going on inside the container trying to get an ip from the host lxd machine? Any ideas are useful I don't have much knowledge with networking

Answer 1

For routed to work, you need to make some configuration in LXD and some configuration in the container. It is easier to create a LXD profile that contains both parts of the configuration.

Here is an example LXD profile. The upper part is about the container configuration, and the below part is what LXD needs to know to configure routed for the container.

config:
  user.network-config: |
    version: 2
    ethernets:
        eth0:
            addresses:
            - 192.168.1.200/32
            nameservers:
                addresses:
                - 8.8.8.8
                search: []
            routes:
            -   to: 0.0.0.0/0
                via: 169.254.0.1
                on-link: true
description: Default LXD profile
devices:
  eth0:
    ipv4.address: 192.168.1.200
    nictype: routed
    parent: enp6s0
    type: nic
name: routed_192.168.1.200
used_by:

To create a container with this profile, you would then run

lxc launch ubuntu: mycontainer --profile default --profile routed_192.168.1.200

References: https://blog.simos.info/how-to-get-lxd-containers-get-ip-from-the-lan-with-routed-network/