#2942 Use teven's thread support to resolve A/AAAA records with libresolv's resolver
Closed: wontfix 4 years ago by pbrezina. Opened 8 years ago by jhrozek.

Ticket was cloned from Red Hat Bugzilla (product Red Hat Enterprise Linux 7): Bug 1097494

Description of problem:

FFS! it's baaaack.
Some juvenile twit thought it was a good idea to ignore two decades of tested
and proven code aka the system resolver library, and of course botched it.

a down/unreachable DNS server (1st position) causes multitude of ping errors
and in some cases (haven't isolated the pathology) after extended period of
errors causes all child processes to be killed and sssd parent itself to shut
down.

eg.
(Wed May 14 02:13:19 2014) [sssd] [ping_check] (0x0020): A service PING timed
out on [ad domain]

in krb5.conf:
[libdefaults]
default_realm = xxx.COM
ticket_lifetime = 1d
renew_lifetime = 3d
dns_lookup_realm = false
dns_lookup_kdc = true
dns_failback = yes

[realms]
xxx.COM = {
        kdc = columbus._sites.xxx.com
        kdc = dallas._sites.xxx.com


Normally dns_failback = no or at least commented out. If the SRV records can't
be found, then the AD module can't do it's thing. I had to set dns_failback=yes
so it would then use the list of KDC servers in the next stanza.

Please note that tools like 'host -t SRV xxx' work just fine and properly
handle unreachable DNS servers NO MATTER HOW MANY THERE ARE!!!!!

So I flipped the 2nd and 1st entries around /etc/resolv.conf and of course it
works. So despite so called fixes theoretically present in 708352 and 703624,
this useless and broken code STILL doesn't BOTHER to look at the next entry let
alone ALL entries.

Version-Release number of selected component (if applicable):
sssd-1.9.2-82

How reproducible:
whenever first DNS server is dead

Steps to Reproduce:
1. have a non-reachable or bogus DNS server in the list of servers in
/etc/resolv.conf
2. start SSSD


Actual results:
(Wed May 14 02:37:36 2014) [sssd[be[xxx.com]]] [be_process_init] (0x0020): No
selinux module provided for [millercoors.com] !!
(Wed May 14 02:37:36 2014) [sssd[be[xxx.com]]] [be_process_init] (0x0020): No
host info module provided for [xxx.com] !!
(Wed May 14 02:37:36 2014) [sssd[be[xxx.com]]] [be_process_init] (0x0020):
Subdomains are not supported for [xxx.com] !!
(Wed May 14 02:37:41 2014) [sssd[be[xxx.com]]] [resolve_srv_done] (0x0020): SRV
query failed: [Successful completion]
(Wed May 14 02:37:41 2014) [sssd[be[xxx.com]]] [fo_resolve_service_send]
(0x0020): No available servers for service 'AD'
(Wed May 14 02:37:41 2014) [sssd[be[xxx.com]]] [sdap_id_op_connect_done]
(0x0020): Failed to connect, going offline (5 [Input/output error])

Expected results:
used the gd! system resolver and rip EVERY shred of this moronic code out of
SSSD and subsystems. There is NO good or defensible reason in any parallel
universe to replace the system resolver library. Ever. Take the author of this
'async resolver' out to the woodshed and Code RED him good!

Additional info:
Where the hell is the QA department who didn't bother to test OBVIOUS failure
modes?

Fields changed

blockedby: =>
blocking: =>
changelog: =>
coverity: =>
design: =>
design_review: => 0
feature_milestone: =>
fedora_test_page: =>
mark: no => 0
milestone: NEEDS_TRIAGE => SSSD 1.15 beta
review: True => 0
selected: =>
testsupdated: => 0

Metadata Update from @jhrozek:
- Issue set to the milestone: SSSD Future releases (no date set yet)

7 years ago

Metadata Update from @thalman:
- Custom field design_review reset (from 0)
- Custom field mark reset (from 0)
- Custom field patch reset (from 0)
- Custom field review reset (from 0)
- Custom field sensitive reset (from 0)
- Custom field testsupdated reset (from 0)
- Issue close_status updated to: None
- Issue tagged with: bugzilla

4 years ago

Metadata Update from @thalman:
- Custom field design_review reset (from false)
- Custom field mark reset (from false)
- Custom field patch reset (from false)
- Custom field review reset (from false)
- Custom field sensitive reset (from false)
- Custom field testsupdated reset (from false)
- Issue tagged with: Canditate to close

4 years ago

Thank you for taking time to submit this request for SSSD. Unfortunately this issue was not given priority and the team lacks the capacity to work on it at this time.

Given that we are unable to fulfill this request I am closing the issue as wontfix.

If the issue still persist on recent SSSD you can request re-consideration of this decision by reopening this issue. Please provide additional technical details about its importance to you.

Thank you for understanding.

Metadata Update from @pbrezina:
- Issue close_status updated to: wontfix
- Issue status updated to: Closed (was: Open)

4 years ago

SSSD is moving from Pagure to Github. This means that new issues and pull requests
will be accepted only in SSSD's github repository.

This issue has been cloned to Github and is available here:
- https://github.com/SSSD/sssd/issues/3983

If you want to receive further updates on the issue, please navigate to the github issue
and click on subscribe button.

Thank you for understanding. We apologize for all inconvenience.

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Metadata