Bug 2187566

Summary:	[Test Only] ML2-OVN Migration support (NFV)
Product:	Red Hat OpenStack	Reporter:	Gurpreet Singh <gurpsing>
Component:	rhosp-openvswitch	Assignee:	OSP Team <rhos-maint>
Status:	CLOSED EOL	QA Contact:	OSP Team <rhos-maint>
Severity:	high	Docs Contact:
Priority:	high
Version:	18.0 (Zed)	CC:	mburns, vkhitrin
Target Milestone:	---	Keywords:	FutureFeature, Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-07-21 00:16:06 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 Gurpreet Singh 2023-04-18 02:15:59 UTC

Description of problem:

OVN migration 

OSP 16.1 introduced an ML2-OVN mechanism driver that adds capabilities for SDN overlays on top of OVS among other benefits. Going forward Red Hat's strategy is to deprecate the ML2-OVS mechanism driver. Starting in OSP 18.0, ML2-OVS will not be supported and the ML2-OVS functionality will be removed.

The transition from ML2-OVS to ML2-OVN can be divided into 2 pillars - (1) ML2-OVS <-> ML2-OVN feature parity (2) ML2-OVS to ML2-OVN migration. 

ML2-OVN migration involves validating the features and the data path types supported




Use Case:

Telco Service Providers deploy OpenStack for NFV workloads using fast datapath types such as OVS-DPDK, SR-IOV, and HWOL. Moving to OVN should not disrupt their current operations or feature capabilities as compared to ML2-OVS. 

Additionally, Telco customers have the requirement of completing the OVN migration of the large-scale cluster (up to 250 nodes) within the maintenance window of fewer than 10 hours and exiting the maintenance window in an operational state. 

The following OVN migration paths are available for the customers:

(1) 16.1 ML2-OVS > 16.2 ML2-OVS > 17.1 ML2-OVS > 17.1 ML2-OVN

(2) 16.2 ML2-OVS > 17.1 ML2-OVS > 17.1 ML2-OVN

(3) 16.2 ML2-OVS > 16.2 ML2-OVN

(4) 17.1 ML2-OVS > 17.1 ML2-OVN

Refer to https://issues.redhat.com/browse/OSP-21921 for more details


Requirement	Details	MVP	Priority	 EPIC
OVN migration for (4) migration path must work for test topology with HWOL, SR-IOV, and OVS-DPDK with no blocking errors	
	Yes	1	

Validate data plane connectivity and operation pos OVN migration for the NFV workloads and data path types	
	Yes	1	

Validate HWOL with VLAN trunk ports	
	Yes	1	

CI test runs for  HWOL, SR-IOV and OVS-DPDK	
	Yes	1	

Support for batch migration where OVN migration can be done for a batch of nodes that do not have the need to communicate with other nodes in the cluster that are outside the batch	
	No	3	

Revert support from ML2-OVN to ML2-OVS on failure (all nodes in the cluster)	
	Yes	1	

Revert support from ML2-OVN to ML2-OVS on failure (all nodes in the batch)	
	No	3	

Recovery from a node crash during OVN migration	
	Yes	1	



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