Bug 2219530 - pods get restarted due to failed probes
Summary: pods get restarted due to failed probes
Keywords:
Status: VERIFIED
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: kernel-rt
Version: 8.6
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Eder Zulian
QA Contact: Waylon Cude
URL:
Whiteboard:
: 2210126 (view as bug list)
Depends On:
Blocks: 2227238 2227239 2227240
TreeView+ depends on / blocked
 
Reported: 2023-07-04 07:22 UTC by cshulyup
Modified: 2023-08-04 23:54 UTC (History)
10 users (show)

Fixed In Version: kernel-rt-4.18.0-505.rt7.294.el8
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 2227238 2227239 2227240 (view as bug list)
Environment:
Last Closed:
Type: Bug
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Gitlab redhat/rhel/src/kernel rhel-8 merge_requests 4978 0 None None None 2023-07-04 12:50:48 UTC
Red Hat Issue Tracker RHELPLAN-161471 0 None None None 2023-07-04 07:25:47 UTC

Description cshulyup 2023-07-04 07:22:52 UTC
The issue doesn't happen when CFS throttling (quota) is disabled or on periodic (nohz=off) kernel.

Probes fails because of exhausted quota.
The quota is exhausted due to delayed quota refill.
The refill is delayed because hrtimers are delayed. 
hrtimers are delayed because of missed interrupts.
Interrupts at missed because of nohz mode.

Steps to Reproduce:
1. install SNO
2. install https://gitlab.cee.redhat.com/cshulyup/vdu-workload-emulator/-/tree/base?ref_type=heads by running script ./add_test-deployments.sh
3. monitor pods restarts with command `oc get pods -n test | grep ago` for 10 (ten) days.

Actual results:
- some pods are restarted after several days

Expected results:
- no single pod restart during 10 days (240 hours)

The fix:
- patch "softirq: Wake ktimers thread also in softirq",
already merged to other branches:
- https://gitlab.com/redhat/rhel/src/kernel/rhel-9/-/merge_requests/695
- https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/2543/


Additional info:
- https://issues.redhat.com/browse/OCPBUGS-3547
- 
https://docs.google.com/document/d/14aYlleo7EaYAjY6QM45AUQ9bw6FUlL20zIkqoyx4PiY/edit#heading=h.jwttsod63yqc

Comment 5 Ming Lei 2023-07-11 01:46:27 UTC
*** Bug 2128603 has been marked as a duplicate of this bug. ***

Comment 6 Eder Zulian 2023-07-11 09:17:01 UTC
*** Bug 2210126 has been marked as a duplicate of this bug. ***

Comment 19 Ming Lei 2023-08-01 02:44:38 UTC
Hello Guys,

Looks the fix only lands kernel-rt, any chance to make it to rhel8.9(kernel)?

Because we have Bug 2128603 which can be fixed by this change.


Thanks,


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