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ofproto/detrace - The missing link.#

Open vSwitch and OVN 2024 Fall Conference (Prague) digest Program Adjacent pick Prague · 20–21 November 2024

Abstract Slides Recording

Speakers: Ales Musil, Dumitru Ceara, Red Hat, Inc.

Play the recording: ofproto/detrace - The missing link.

Why: The debugging story across OVS/OVN's abstraction layers finally gets a one-command answer — new in OVS 3.4.

What: ofproto/detrace takes a datapath flow's UFID and outputs the OpenFlow rules and groups that contributed to its creation, bridging the gap between optimized kernel flows and the controller-configured pipeline that produced them.

How: The chain is: UFID → OpenFlow cookies → (with ovn-detrace) OVN Southbound Logical_Flows via stage-hints → Northbound objects (Port_Bindings, Load_Balancer VIP mappings, ACLs). The worked example walks a Geneve-encapsulated, DNAT'd connection from dpctl/dump-flows output all the way to the specific load balancer VIP.

Where applicable: Any OVS/OVN deployment on OVS ≥ 3.4; the mantra — "UFIDs → cookies → stage-hints → external-ids" — is worth remembering regardless of tooling.