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Bug 2293368

Summary:	overcloud images have console=ttyS0 in their default boot arguments
Product:	Red Hat OpenStack	Reporter:	Robin Jarry <rjarry>
Component:	rhosp-director-images	Assignee:	Julia Kreger <jkreger>
Status:	CLOSED ERRATA	QA Contact:	David Rosenfeld <drosenfe>
Severity:	high	Docs Contact:
Priority:	high
Version:	17.1 (Wallaby)	CC:	astupnik, bshephar, hjensas, jamsmith, jkreger, jkreger, joflynn, mariel, pweeks, sbaker, tsaito
Target Milestone:	z4	Keywords:	Triaged
Target Release:	17.1	Flags:	jkreger: needinfo-
Hardware:	Unspecified
OS:	Linux
Whiteboard:
Fixed In Version:	diskimage-builder-3.31.1-17.1.20240905210750.0576fad.el9ost openstack-tripleo-common-15.4.1-17.1.20240911100820.e5b18f2.el9ost	Doc Type:	Bug Fix
Doc Text:	This RHOSP 17.1.4 update fixes a bug that caused packet transmission latency in certain situations. + Before this bug fix, if your RHOSP 17.1 deployment included a filter rule in nft or iptables with a LOG action, and the kernel command line (/proc/cmdline) has console=tty50, logging actions could cause substantial latency in packet transmission. + This bug fix fixes the bug and eliminates the latency. An update from 17.1.x to 17.1.4 does not automatically apply the fix. If you want the fix, before updating to 17.1.4, perform the steps in the Knowledgebase solution: link:https://access.redhat.com/solutions/7076184[Sometimes receiving packet(e.g. ICMP echo) has latency, around 190 ms].	Story Points:	---
Clone Of:		Environment:
Last Closed:	2024-11-21 09:41:21 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:
Bug Depends On:	2179366
Bug Blocks:	2276671, 2317182

Description Robin Jarry 2024-06-20 14:29:38 UTC

Description of problem:

The default console in overcloud images is now the serial console. This can cause latency issues. See bz 2276671 for more details.

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

17.1

How reproducible:

all the time

Steps to Reproduce:

1. Boot an overcloud image.

Actual results:

The console output is redirected to serial (console=ttyS0).

Expected results:

There should be no console= arguments

Additional info:

I am probably responsible for this problem (see https://bugzilla.redhat.com/show_bug.cgi?id=2179366#c32 for more details). I assumed that removing console=tty0 would leave no console arguments. I was mistaken. Since the original problem was caused by "nomodeset", we should probably revert to "console=tty0" and make sure not to add "nomodeset" back.

Comment 1 Robin Jarry 2024-06-20 14:43:31 UTC

Since we're talking about adding console=tty0 back. We will probably need to make some additional changes to cover the risks I was talking about in https://bugzilla.redhat.com/show_bug.cgi?id=2179366#c32.

1) Disable kernel logging to the console after boot is complete with a sysctl configuration file.
2) Get rid of the iptables rule that logs every dropped packets (see bz 2293382)

Comment 2 Julia Kreger 2024-06-21 16:12:30 UTC

I think the disable via sysctl might not be a great idea, the interrupts on the buffer, at least in a VM seem far less and seem stable.

The iptables change is a separate BZ it looks like and that should be okay.

I've posted changes to diskimage-builder to give us the basic knobs to disable serial console, which would acutally be better overall. I guess we'll see from there.

Comment 10 Brendan Shephard 2024-07-31 01:35:16 UTC

*** Bug 2301447 has been marked as a duplicate of this bug. ***

Comment 27 errata-xmlrpc 2024-11-21 09:41:21 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 (RHOSP 17.1.4 bug fix and enhancement advisory), 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-2024:9974

Comment 28 Red Hat Bugzilla 2025-03-22 04:25:21 UTC

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 120 days