OpenWrt in LXC containers

OpenWrt can run inside a LXC container, using the same kernel as running on the host system. This can be useful for development as well as for VM hosting.

The following gives a rough idea on how to get things up and running. Before anything, install LXC on the host machine and make sure it supports running unprivileged containers.

There is currently no template for OpenWrt available, so some manual steps are required.

1. Create the VM folder manually at .local/share/lxc/<vm-name>/
2. Download a snapshot rootfs of OpenWrt and unpack it to .local/share/lxc/<vm-name>/rootfs
3. Create a .local/share/lxc/<vm-name>/config containing the following content:
   

   lxc.include = /etc/lxc/default.conf
   lxc.include = /usr/share/lxc/config/common.conf
   lxc.include = /usr/share/lxc/config/userns.conf
   lxc.arch = linux64
   
   # find your ids via
   # cat  /etc/s*id|grep $USER
   lxc.idmap = u 0 100000 65536
   lxc.idmap = g 0 100000 65536
   
   lxc.mount.auto = proc:mixed sys:ro cgroup:mixed
   
   # lan interface
   lxc.net.0.type = veth
   
   # wan interface
   lxc.net.1.type = veth
   lxc.net.1.link = lxcbr0
   
   # adapt <user> and <vm-name>
   lxc.rootfs.path = dir:/home/<user>/.local/share/lxc/<vm-name>/rootfs

4. run chmod on the rootfs folder with the id you obtained earlier
5. run lxc-start -n <vm-name>