Bug 1836910

Summary:	Rhel7.7 server have an issue regarding dyndns update for PTR-records which is done by sssd on active directory DNS servers. It is done in two steps (two different nsupdate messages).
Product:	Red Hat Enterprise Linux 7	Reporter:	Abhijit Roy <abroy>
Component:	sssd	Assignee:	Tomas Halman <thalman>
Status:	CLOSED ERRATA	QA Contact:	sssd-qe <sssd-qe>
Severity:	low	Docs Contact:
Priority:	unspecified
Version:	7.7	CC:	atikhono, dlavu, grajaiya, jhrozek, lslebodn, mzidek, nsoman, pbrezina, sgoveas, thalman, tscherf
Target Milestone:	rc	Keywords:	Triaged
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:	sync-to-jira, review
Fixed In Version:	sssd-1.16.5-8.el7	Doc Type:	If docs needed, set a value
Doc Text:	New option is introduced with this patch (`dyndns_update_per_family`)	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-09-29 19:50:32 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Abhijit Roy 2020-05-18 13:28:05 UTC

Description of problem:

Rhel7.7 server have and issue regarding dyndns update for PTR-records which is done by sssd on active directory DNS servers. It is done in two steps (two different nsupdate messages). One for update delete
(Mon Dec 30 15:22:38 2019) [sssd[be[x5.ru]]] [be_nsupdate_create_ptr_msg] (0x0400):  -- Begin nsupdate message --

update delete 55.123.168.192.in-addr.arpa. in PTR
send
-- End nsupdate message –
and then for update add
(Mon Dec 30 15:22:38 2019) [sssd[be[x5.ru]]] [be_nsupdate_create_ptr_msg] (0x0400):  -- Begin nsupdate message --

update add 55.123.168.192.in-addr.arpa. 60 in PTR tst-rhel77-d1.x5.ru.
send
-- End nsupdate message –

The here problem is that these request may be allocated to different domain controllers, and, assuming there is a lag of DNS syncronizations betweeen them, it leads to a situation when PTR record is deleted on one DC-server (server A), then PTR record is added on another DC-server (server B), and then server A replicates deletion to server B. As a result - server losts it's PTR record.

This problem is also described more detailed here: https://pagure.io/SSSD/sssd/issue/3829. 

There is stated, that fix had been done for rhel7 upstream about a year ago, but the problem persists on our rhel 7.7 servers. Is there any way to backport "dyndns_update_per_family" option from sssd 2.2, which fixes the issue?

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


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Comment 5 Alexey Tikhonov 2020-05-27 08:35:53 UTC

    sssd-1-16
        6a77f94 - DYNDNS: SSSD does not batch DDNS update requests

Comment 6 Alexey Tikhonov 2020-05-27 08:37:39 UTC

Hi Tomas,

taking into the account new option introduced with this patch (`dyndns_update_per_family`), do you think it makes sense to add a Doc Text note?

Comment 9 Namita Soman 2020-06-09 10:55:55 UTC

Alexey, can you pls provide steps to verify this

Comment 10 Alexey Tikhonov 2020-06-09 11:48:00 UTC

(In reply to Namita Soman from comment #9)
> Alexey, can you pls provide steps to verify this

Sorry, I don't have an idea from the top of my head.
May be Tomas (patch author) might help.

Comment 11 Dan Lavu 2020-06-16 04:26:12 UTC

Verified against sssd-1.16.5-10.el7.x86_64 


Used nsupdate and performed all commands in the upstream unit test. 
https://github.com/SSSD/sssd/pull/696/files#diff-4f6b8baf29b2a940c5444ed6a1f5b479R400

Comment 12 Tomas Halman 2020-08-21 09:30:24 UTC

Sorry for late reply. I do not think we need additional doc text here. It is not big change and the man page update is enough.

Comment 14 errata-xmlrpc 2020-09-29 19:50:32 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (sssd bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:3904