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Bug 1755902

Summary: RFE: Support reapply MTU changes.
Product: Red Hat Enterprise Linux 8 Reporter: Gris Ge <fge>
Component: nmstateAssignee: Gris Ge <fge>
Status: CLOSED WONTFIX QA Contact: Mingyu Shi <mshi>
Severity: medium Docs Contact:
Priority: medium    
Version: 8.1CC: edwardh, jiji, jishi, kanderso, mshi, network-qe
Target Milestone: rcKeywords: RFE
Target Release: 8.1Flags: pm-rhel: mirror+
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: nmstate-0.1.1-2.el8 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 1779859 (view as bug list) Environment:
Last Closed: 2020-01-13 05:58:42 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: 1779859    

Description Gris Ge 2019-09-26 12:32:01 UTC
Description of problem:

Support change MTU with link state changes.

Version-Release number of selected component (if applicable):
nmstate-0.0.8-15.el8

How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:


Expected results:


Additional info:

Comment 3 Mingyu Shi 2019-09-29 02:44:24 UTC
Gris, What does it mean? Is it a bug of wrong debug information?

Because I just met the situation: 
changed the mtu with the file:
---
interfaces:
- name: veth1
  type: ethernet
  state: up
  mtu: 2000

The debugger reported '2019-09-26 04:01:01,411 root         DEBUG    Device reapply does not support mtu changes, fallback to device activation: dev=veth1', but it works as well.

Seems it does support reapply mtu changes.

Comment 4 Gris Ge 2019-10-09 08:09:34 UTC
Hi Mingyu,

The `reapply()` means the link will not be bring down and up.

You may use `ip monitor dev <nic_name>` to check on link status changes.

For example, adding slaves to bridge will use `reapply` will keep the bridge interface always in up state.

Comment 5 Edward Haas 2019-10-27 20:36:57 UTC
This issue may have been solved by https://bugzilla.redhat.com/1702657

Comment 6 Gris Ge 2019-11-14 13:29:05 UTC
(In reply to Edward Haas from comment #5)
> This issue may have been solved by https://bugzilla.redhat.com/1702657

No. NM fixed the reapply issue, but nmstate hard coded not to do reapply on MTU changes.

This bug is ask nmstate to remove that hard coded restriction.

Comment 9 Mingyu Shi 2019-12-04 10:11:11 UTC
Investigating:
RHEL-8.1.1-20191202.n.3 

[root@hp-dl388g8-04 /mnt/tests/kernel/networking/nmstate/temp]0# rpm -q NetworkManager nmstate
NetworkManager-1.20.0-3.el8.x86_64
nmstate-0.1.1-5.el8.noarch

"ip monitor" command still detected the link change even do 'nmstatectl set $sameYamlFile'