Bug 1972636

Summary: [MTU] MTU gets lowered by 1 after applying route rules
Product: Red Hat Enterprise Linux 8 Reporter: Ales Musil <amusil>
Component: nmstateAssignee: Gris Ge <fge>
Status: CLOSED ERRATA QA Contact: Mingyu Shi <mshi>
Severity: high Docs Contact:
Priority: unspecified    
Version: 8.4CC: ferferna, jiji, jishi, mburman, network-qe, till
Target Milestone: betaKeywords: Regression, Triaged
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: No Doc Update
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-11-09 17:43:51 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:    
Bug Blocks: 1962563    
Attachments:
Description Flags
Reproducer none

Description Ales Musil 2021-06-16 11:05:22 UTC 
Created attachment 1791524 [details]
Reproducer

Description of problem:
When applying route rules to bridge with default MTU 1500, the MTU is lowered by 1 to 1499. 

Version-Release number of selected component (if applicable):
nmstate-2.0.0 latest git base

How reproducible:
100%

Steps to Reproduce:
1. Run reproducer script


Actual results:
-  mtu: 1500
+  mtu: 1499


Expected results:
The MTU should stay the same.

Additional info:
I was able to track down start of this failure to PR#1595
https://github.com/nmstate/nmstate/pull/1595

However I am not really sure if it\s the root cause.
Comment 1 Gris Ge 2021-06-18 06:57:07 UTC 
RHV confirmed the scratch/copr build fixed the issue.
Comment 4 Mingyu Shi 2021-07-21 08:00:49 UTC 
Verified with versions:
nmstate-1.1.0-1.el8.noarch
nispor-1.1.1-1.el8.x86_64
NetworkManager-1.32.3-0.z.2.20e3975fd2.el8.x86_64
Comment 6 errata-xmlrpc 2021-11-09 17:43:51 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 (nmstate 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-2021:4157