Bug 1779105

Summary: MTU not being set correctly on ovn-kubernetes
Product: OpenShift Container Platform Reporter: Casey Callendrello <cdc>
Component: NetworkingAssignee: Phil Cameron <pcameron>
Networking sub component: ovn-kubernetes QA Contact: Anurag saxena <anusaxen>
Status: CLOSED ERRATA Docs Contact:
Severity: high    
Priority: high CC: bbennett, zzhao
Version: 4.3.0   
Target Milestone: ---   
Target Release: 4.4.0   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-05-13 21:53:38 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:

Description Casey Callendrello 2019-12-03 10:22:26 UTC
We aren't setting the MTU correctly on OVN-kubernetes. For example, on an AWS node (which has 9001 uplink mtu), pods only have 1400 MTU:

bash-5.0# ip link
3: eth0@if178: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1400 qdisc noqueue state UP mode DEFAULT group default 
    link/ether c6:f1:51:81:00:19 brd ff:ff:ff:ff:ff:ff link-netnsid 0


This is an annoyance on AWS, but is a blocker bug for GCP (which has a less-than-1500 uplink MTU.

Comment 1 Phil Cameron 2019-12-04 20:29:27 UTC
This is being fixed as part of 
https://jira.coreos.com/browse/SDN-456

Comment 2 Phil Cameron 2019-12-04 20:42:23 UTC
Also see https://jira.coreos.com/browse/SDN-498

Comment 5 zhaozhanqi 2020-01-13 07:05:05 UTC
this bug has been fixed in 4.4.0-0.nightly-2020-01-13-010304

 ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
3: eth0@if25: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 8901 qdisc noqueue state UP 
    link/ether 86:f1:6e:80:02:10 brd ff:ff:ff:ff:ff:ff

Comment 7 errata-xmlrpc 2020-05-13 21:53:38 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, 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-2020:0581