Bind mount /run read-only
Created by: tomty89
Avoid e.g. systemd-tmpfiles from tampering /run (of the host):
fchownat() of /run/systemd/netif failed: Read-only file system fchownat() of /run/systemd/netif/links failed: Read-only file system fchownat() of /run/systemd/netif/leases failed: Read-only file system fchownat() of /run/systemd/netif/lldp failed: Read-only file system
In this particular case, it could cause unexpected (and unnecessary) change of ownership to these directories (because of automatic uid/gid allocation), which could prevent systemd-networkd from working.
Besides, the chroot should under no circumstances (actually) need any (read-)write access to /run. If there's such need, we should not bind mount.