lxc and interface lo does not exist in virtualized server

Virtualizing a real server with an LXC container is pretty easy – do a rsync and run it. Sometimes there are some glitches when starting the LXC container for the first time. Such errors like the following – no networking available at the start, but when attached to the started container it seems to have the network interfaces with no IPs. Even, though it is possible to set the IPs manually the init scripts do not work.

[root@srv ~]# lxc-start -F -n n7763.node-int.info
lxc-start: live300.mytv.bg: start.c: proc_pidfd_open: 1607 Function not implemented - Failed to send signal through pidfd
INIT: version 2.88 booting

   OpenRC 0.12.4 is starting up Gentoo Linux (x86_64) [LXC]

 * /proc is already mounted
 * Mounting /run ... * /run/openrc: creating directory
 * /run/lock: creating directory
 * /run/lock: correcting owner
 * Caching service dependencies ... [ ok ]
 * setting up tmpfiles.d entries for /dev ... [ ok ]
 * Creating user login records ... [ ok ]
 * Wiping /tmp directory ... [ ok ]
 * Bringing up network interface lo ...RTNETLINK answers: File exists
 [ ok ]
 * Updating /etc/mtab ... [ ok ]
 * Bringing up interface lo
 *   ERROR: interface lo does not exist
 *   Ensure that you have loaded the correct kernel module for your hardware
 * ERROR: net.lo failed to start
 * setting up tmpfiles.d entries ... [ ok ]
INIT: Entering runlevel: 3
 * Loading iptables state and starting firewall ... [ ok ]
 * Bringing up interface lo
 *   ERROR: interface lo does not exist
 *   Ensure that you have loaded the correct kernel module for your hardware
 * ERROR: net.lo failed to start
 * Bringing up interface eth0
 *   ERROR: interface eth0 does not exist
 *   Ensure that you have loaded the correct kernel module for your hardware
 * ERROR: net.eth0 failed to start

And it appeared that the old /dev was still in place, which messed up with virtualization and the init scripts.
The solution is simple just

  1. remove the existing /dev
  2. create a new empty one

And the LXC container of the real server will start with a network as usual.

So when virtualizing a real server into LXC container after doing RSYNC of the storage, it is mandatory to create an empty /dev, /proc, and /sys directories!

More on the LXC containers – Run LXC CentOS 8 container with bridged network under CentOS 8.

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