Description of problem:

Man sssd-ipa(5) says

       dyndns_refresh_interval (integer)
           How often should the back end perform periodic DNS update in
           addition to the automatic update performed when the back end goes
           online. This option is optional and applicable only when
           dyndns_update is true.

           Default: 0 (disabled)

suggesting that even when this option is not set (the default), when
dyndns_update = True is set, the IP address update in DNS should happen upon
backend going online, meaning during systemctl start sssd.service.

That does not seem to be happening.

Version-Release number of selected component (if applicable):

sssd-ipa-2.1.0-2.fc29.x86_64

How reproducible:

Deterministic.

Steps to Reproduce:
1. I'm running this in container which makes it easy for me to change IP
address.
2. On the (future) IPA client machine, run ipa-client-install with
--enable-dns-updates
3. Observe that the IP address got set in DNS.
4. Change the IP address of the IPA client machine.
5. Run systemctl restart sssd.service.
6. Check the IP address of the IPA client machine in IPA server's DNS.

Actual results:

Old IP address.

Expected results:

New IP address.

Additional info:

In the log, I see

[ipa_init_dyndns] (0x0100): Dynamic DNS updates are on. Checking for
nsupdate...
[ipa_init_dyndns] (0x0100): nsupdate is available
[ipa_dyndns_init] (0x0040): Dyndns task can't be started,
dyndns_refresh_interval is 0
[ipa_init_dyndns] (0x0080): Failure setting up automatic DNS update

but no mention of the IP address getting updated.

When I set dyndns_refresh_interval to non-zero value, I see the update refresh
happening.

Alexander suggests that the refactoring in
https://github.com/SSSD/sssd/commit/df9e4802c060fc21d38f238265805092352e5c95
might not have covered the initial sync feature.