Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.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 1833373

Summary:	[OVN SCALE] Improve Load Balancer Hairpin detection/scalability
Product:	Red Hat Enterprise Linux Fast Datapath	Reporter:	Dumitru Ceara <dceara>
Component:	OVN	Assignee:	Numan Siddique <nusiddiq>
Status:	CLOSED ERRATA	QA Contact:	ying xu <yinxu>
Severity:	low	Docs Contact:
Priority:	low
Version:	FDP 20.C	CC:	ctrautma, dcbw, mark.d.gray, nusiddiq, trozet
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	ovn2.13-20.09.0-14	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-03-25 19:06:08 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:	1859924

Description Dumitru Ceara 2020-05-08 14:26:44 UTC

Description of problem:
In order to detect that the backend selected for load balanced traffic is actually the source of the traffic (i.e., hairpin) OVN currently creates 2 logical flows per VIP in table LS_IN_PRE_HAIRPIN. The flow match field looks like:

Initiator traffic:
(ip.src == backend-ip1 && ip.dst == backend-ip2) || .. || (ip.src == backend-ipn && ip.dst == backend-ipn)

Reply traffic:
((ip.src == backend-ip1) || .. || (ip.src == backend-ipn)) && ip.dst = VIP

This gets processed by ovn-controller and translated into 2 * N openflow entries.

A better approach would be to create a new SB DB table, e.g., Hairpin_Endpoints with columns
- datapath
- dest_ip (VIP)
- dest_port (VIP-port)
- proto
- sources (list of backend IPs & ports)

ovn-northd would populate this table for all Load_Balancer VIPs (currently hairpin is supported only for logical switches but could be extended to logical routers too) and ovn-controller would generate the required openflow entries that perform hairpin detection.

Comment 2 Dan Williams 2021-03-25 19:06:08 UTC

Shipped in FDP 20.I