Короче, в работе systemd-nspawn я заметил такой косяк:
root@ne-vlezay80:~# tail /var/log/syslog
Jun 13 12:15:04 ne-vlezay80 systemd-nspawn[7473]: Failed to add new veth interfaces: File exists
Jun 13 12:15:04 ne-vlezay80 systemd[1]: ppp.service: main process exited, code=exited, status=239/n/a
Jun 13 12:15:04 ne-vlezay80 systemd[1]: Unit ppp.service entered failed state.
Jun 13 12:15:23 ne-vlezay80 systemd[1]: Starting Container ppp...
Jun 13 12:15:23 ne-vlezay80 systemd[1]: Started Container ppp.
Jun 13 12:15:23 ne-vlezay80 systemd[1]: Starting Container ppp.
Jun 13 12:15:23 ne-vlezay80 systemd[1]: Started Container ppp.
Jun 13 12:15:23 ne-vlezay80 systemd-nspawn[7533]: Failed to add new veth interfaces: File exists
Jun 13 12:15:23 ne-vlezay80 systemd[1]: ppp.service: main process exited, code=exited, status=239/n/a
Jun 13 12:15:23 ne-vlezay80 systemd[1]: Unit ppp.service entered failed state.