Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.

The FDP team is no longer accepting new bugs in Bugzilla. Please report your issues under FDP project in Jira. Thanks.

Bug 2067216

Summary:	[EL9] add-port creates interfaces with the same MAC address on different nodes
Product:	Red Hat Enterprise Linux Fast Datapath	Reporter:	Cédric Jeanneret <cjeanner>
Component:	openvswitch2.15	Assignee:	Open vSwitch development team <ovs-team>
Status:	CLOSED NOTABUG	QA Contact:	ovs-qe
Severity:	urgent	Docs Contact:
Priority:	urgent
Version:	RHEL 9.0	CC:	apevec, ctrautma, jhsiao, ralongi
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-03-24 13:34:50 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 Cédric Jeanneret 2022-03-23 14:44:50 UTC

Description of problem:
While testing EL9 and OSP-17, we're facing an issue with openvswitch2.15:
running this command on 2 different nodes on the same network leads to both ports having the same MAC address, leading to obvious networking issues:

ovs-vsctl add-port br-ex vlan103 tag=103 -- set interface vlan103 type=internal

In order to ensure it's not already patched, we've upgraded openvswitch to this build:
https://brewweb.engineering.redhat.com/brew/buildinfo?buildID=1938775

Some more notes:
- env is running on libvirt (multiple VMs on libvirt)
- env is using a single bridge exposed from the hypervisor
- env is running with latest EL9 qcow2 image and latest "overcloud-hardened-uefi-full" image provided by OSP.

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


How reproducible:
Always

Steps to Reproduce:
1. Get 2 nodes on the same network
2. ovs-vsctl add-port br-ex vlan103 tag=103 -- set interface vlan103 type=internal
3. check the MAC addresses on those ports (ip link show vlan103)

Actual results:
the MAC addresses are the same on both nodes, preventing any networking to actually work

Expected results:
MAC addresses should be different

Additional info:
This happens when trying to deploy an OSP-17 overcloud with latest compose available.

Comment 1 Cédric Jeanneret 2022-03-23 14:46:16 UTC

(note: I can't set the "Version" to the right value since "RHEL 9.0" doesn't exist in the list)

Comment 2 Cédric Jeanneret 2022-03-24 13:34:50 UTC

Hello,

Closing this, found out the actual issue:
- I'm editing a base image using virt-sysprep
- that base image is then used to provision the other VMs

According to https://bugzilla.redhat.com/show_bug.cgi?id=1554546, virt-customize (as well as virt-sysprep) generates a machine-id; since the image is then used to provision a bunch of VM, they end up with the same machine-id.

So it appears OVS is using the machine-id under some conditions in order to generate MAC for vlan ports. At least, that's my thinking, since ensuring I get different machine-id on the VMs shows different MAC addresses being generated, leading to a working network now.

Sorry for the noise.

Cheers,

C.