Bug 2314343

Summary:	Add support for ifcfg LINKSTATUS=down in os-net-config
Product:	Red Hat OpenStack	Reporter:	Dan Sneddon <dsneddon>
Component:	os-net-config	Assignee:	Dan Sneddon <dsneddon>
Status:	CLOSED NEXTRELEASE	QA Contact:	Eran Kuris <ekuris>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	17.1 (Wallaby)	CC:	bfournie, jmarti, jslagle, mburns
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Cause: OVS-DPDK User Bridges that have no IP and are only used for provider networks do not require an active internal interface to the kernel. OVS-DPDK User Bridges should remain in a DOWN state when the bridge is enabled. Consequence: If the OVS User Bridge interface is set to UP the kernel will receive unnecessary broadcast and multicast traffic which it has to drop, which uses extra CPU. Fix: The network template for os-net-config now supports the “ovs_internal: [TRUE\|FLASE]” parameter. If set to false “LINKSTATUS=down” will be added to the ifcfg file when using the ifcfg provider, which will keep the internal interface disabled. Result:	Story Points:	---
Clone Of:		Environment:
Last Closed:	2024-10-01 12:38:06 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 Dan Sneddon 2024-09-23 22:28:32 UTC

Description of problem:
OVS-DPDK User Bridges may be standalone and do not require an active kernel interface. There is a setting for ifcfg files in network-init-scripts that allows this behavior. Add support in os-net-config for setting LINKSTATUS=down in user bridge ifcfg files when using init-scripts instead of NetworkManager

Version-Release number of selected component (if applicable):
17.1.4

How reproducible:
100%

Steps to Reproduce:
1. Configure an ovs-DPDK user_bridge with no IP address
2. Run os-net-config 
3. Bring up the OVS user bridge

Actual results:

The user bridge is brought up with an active kernel interface, which leads to broadcast and multicast traffic hitting the kernel and using excess CPU

Expected results:

The OVS user bridge should be down and not show as “DOWN” in “ip addr”

Additional info:

A fix was made in init-scripts but this support was not added to os-net-config before as there was not a use case before, but now we have a customer who wishes to use the OVS user bridge without support for tunnel networks and needs this feature for maximum provider network performance.