Arch Linux

Following update from Samba 4.9.5 to 4.10.0, samba dnsupdate fails.

Additional info:

* package version(s): Samba 4.10.0
* config and/or log files etc.

At startup:

samba[1245]: task[dnsupdate][1245]: [2019/03/23 12:33:36.171895, 0] ../../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
samba[1245]: task[dnsupdate][1245]: /usr/bin/samba_dnsupdate: Traceback (most recent call last):
samba[1245]: task[dnsupdate][1245]: [2019/03/23 12:33:36.171976, 0] ../../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
samba[1245]: task[dnsupdate][1245]: /usr/bin/samba_dnsupdate: File "/usr/bin/samba_dnsupdate", line 56, in <module>
samba[1245]: task[dnsupdate][1245]: [2019/03/23 12:33:36.171989, 0] ../../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
samba[1245]: task[dnsupdate][1245]: /usr/bin/samba_dnsupdate: import dns.resolver
samba[1245]: task[dnsupdate][1245]: [2019/03/23 12:33:36.172000, 0] ../../lib/util/util_runcmd.c:327(samba_runcmd_io_handler)
samba[1245]: task[dnsupdate][1245]: /usr/bin/samba_dnsupdate: ModuleNotFoundError: No module named 'dns'
samba[1245]: task[dnsupdate][1245]: [2019/03/23 12:33:36.191397, 0] ../../source4/dsdb/dns/dns_update.c:331(dnsupdate_nameupdate_done)
samba[1245]: task[dnsupdate][1245]: dnsupdate_nameupdate_done: Failed DNS update with exit code 1

* link to upstream bug report, if any. Not applicable.

Steps to reproduce:

1. Install Samba and configure as AD domain controller, eg. as per https://wiki.archlinux.org/index.php/Samba/Active_Directory_domain_controller.
2. Update Arch Linux (pacman -Syu) to update Samba from 4.9.5 to 4.10.0.
3. Samba dnsupdate fails at startup.

Fix is simple: install 'python-dnspython' (eg. pacman -S python-dnspython) and restart Samba. No error occurs.

So it's just a missing dependency, probably only applicable to Samba AD installations.