[Samba] Samba AD DC tries to start and fails on reboot

[Jonathan Kreider]

OS = Ubuntu 18.04 LXD container
Samba version = 4.11.12
Repo = Louis' (many thanks)

I recently upgraded from 4.10.14->4.10.17->4.11.12

Now the samba-ad-dc service fails with the following upon reboot:
---
root at samba:~# systemctl status samba-ad-dc
● samba-ad-dc.service - Samba AD Daemon
   Loaded: loaded (/lib/systemd/system/samba-ad-dc.service; enabled; vendor
preset: enabled)
   Active: failed (Result: exit-code) since Tue 2020-09-15 19:16:16 EDT;
57s ago
     Docs: man:samba(8)
           man:samba(7)
           man:smb.conf(5)
  Process: 213 ExecStart=/usr/sbin/samba --foreground --no-process-group
$SAMBAOPTIONS (code=exited, status=1/FAILURE)
 Main PID: 213 (code=exited, status=1/FAILURE)

Sep 15 19:16:06 samba samba[341]:   task_server_terminate:
task_server_terminate: [kdc failed to setup interfaces]
Sep 15 19:16:06 samba samba[338]: [2020/09/15 19:16:06.375707,  0]
../../source4/cldap_server/cldap_server.c:130(cldapd_add_socket)
Sep 15 19:16:06 samba samba[338]:   Failed to bind to
ipv6:fd61:5ced:6c27:0:216:3eff:fe9b:802a:389 -
NT_STATUS_ADDRESS_NOT_ASSOCIATED
Sep 15 19:16:06 samba samba[338]: [2020/09/15 19:16:06.375968,  0]
../../source4/smbd/service_task.c:36(task_server_terminate)
Sep 15 19:16:06 samba samba[338]:   task_server_terminate:
task_server_terminate: [cldapd failed to setup interfaces]
Sep 15 19:16:06 samba samba[213]: [2020/09/15 19:16:06.399691,  0]
../../source4/smbd/server.c:371(samba_terminate)
Sep 15 19:16:06 samba samba[213]:   samba_terminate: samba_terminate of
samba 213: kdc failed to setup interfaces
Sep 15 19:16:06 samba systemd[1]: samba-ad-dc.service: Main process exited,
code=exited, status=1/FAILURE
Sep 15 19:16:16 samba systemd[1]: samba-ad-dc.service: Failed with result
'exit-code'.
Sep 15 19:16:16 samba systemd[1]: Failed to start Samba AD Daemon.
---

If I manually start it:
$ systemctl start samba-ad-dc
then it loads ok.

Is the systemd unit file missing a dependency? I compared the version
between an AD running 4.10.14 and 4.11.12(this current problem machine) and
the one difference between the two is that resolveconf.service is listed as
a dependency in 4.11.12 and not in the older version.

$ systemctl list-dependencies samba-ad-dc
● ├─system.slice
● ├─network-online.target
● │ └─systemd-networkd-wait-online.service
● └─sysinit.target
●   ├─apparmor.service
●   ├─blk-availability.service
●   ├─dev-hugepages.mount
●   ├─dev-mqueue.mount
●   ├─keyboard-setup.service
●   ├─kmod-static-nodes.service
●   ├─lvm2-lvmetad.socket
●   ├─lvm2-lvmpolld.socket
●   ├─lvm2-monitor.service
●   ├─open-iscsi.service
●   ├─plymouth-read-write.service
●   ├─plymouth-start.service
●   ├─proc-sys-fs-binfmt_misc.automount
●   ├─resolvconf.service   ## this is the only change
●   ├─setvtrgb.service
●   ├─sys-fs-fuse-connections.mount
●   ├─sys-kernel-config.mount
●   ├─sys-kernel-debug.mount
●   ├─systemd-ask-password-console.path
●   ├─systemd-binfmt.service
●   ├─systemd-hwdb-update.service
●   ├─systemd-journal-flush.service
●   ├─systemd-journald.service
●   ├─systemd-machine-id-commit.service
●   ├─systemd-modules-load.service
●   ├─systemd-random-seed.service
●   ├─systemd-sysctl.service
●   ├─systemd-timesyncd.service
●   ├─systemd-tmpfiles-setup-dev.service
●   ├─systemd-tmpfiles-setup.service
●   ├─systemd-udev-trigger.service
●   ├─systemd-udevd.service
●   ├─systemd-update-utmp.service
●   ├─cryptsetup.target
●   ├─local-fs.target
●   │ └─systemd-remount-fs.service
●   └─swap.target

However, I'm using netplan not resolveconf (I think...)
# systemctl status resolveconf
Unit resolveconf.service could not be found.

I ran Louis' script and can post it if it will help.

Thanks,
Jonathan Kreider