[Spce-user] SOLVED: mr13.5.1 [sysemctl] Job for networking.service failed because the control process exited with error code

[SPCE Newbie]

Steps to reproduce:

1.  Fresh install with single dhcp (private) ipv4 network interface
...
2.  Define currently allocated address as static by editing network.yml
3.  Enable second (public) static interface by editing network.yml
4.  ngcpcfg apply
5.  Enable firewall by editing security.firewall.enable in config.yml
6.  Run run ngcp-iptables-apply but don't remote ssh-in in-time
7.  Experience existing remote ssh session continuing normally
8.  Experience existing remote web admin session become unresponsive
9.  Experience new remote ssh attempts fail
10. Verify that tcp/22 and tcp/1443 have appropriate listeners with ss
11. Verify that sno ssh or https fw rules exist with nft list ruleset
12. Reboot
13. See error in subject line in systemctl status
14. Inspect network interface statuses in /var/run/network
15. Add missing interface for any zero-length interface, e.g.
    # echo neth1 > /var/run/network/ifstate.neth1
16. Remove, now redundant, leases file, e.g.
17. # rm /var/lib/dhcp/dhclient.neth0.leases
18. Verify that `systemctl restart networking.service` no-longer errors

Likely root causes:
1.  Subsequent change of addressing from dynamic to static, coupled-with
2.  Binary /usr/sbin/ifup calling dhclient with now removed -I option

Notes:
Inevitably many newbie missteps (the leases file contained many prior
allocations from reboots etc.) so 1..18 may include irrelevant steps
and/or be incomplete.  Solution (15-16) worked here however.