Paweł Gronowski c621624e2f libnetwork: Always clean up endpoint driver info in sbLeave ...

In Swarm overlay networks, remote nodes program VXLAN FDB and neighbor
entries from the overlay driver's NetworkDB table (overlay_peer_table).
Those entries are installed as static/permanent neighbors and are
removed only when the endpoint's driver table entries are deleted from
NetworkDB and the delete event is gossiped to peers.

Endpoint.sbLeave() updates the local endpoint object in the store via
storeEndpoint(). If that store update fails (notably
datastore.ErrKeyModified from a boltDB CAS conflict during concurrent
endpoint operations), sbLeave() returned early without calling
deleteDriverInfoFromCluster(). This left the endpoint's
overlay_peer_table record behind in NetworkDB, so no DELETE gossip event
was emitted, and remote nodes never removed the corresponding
neighbor/FDB state. This causes stale permanent ARP/FDB entries to
accumulate in overlay network namespaces, eventually blackholing TCP
traffic and producing intermittent 502/504 until the service is
redeployed.

Fix this by removing the early return on storeEndpoint failure.
Instead, accumulate errors and continue the full leave operation.

Assisted-by: GPT-5.2 (AI)
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

2026-04-16 12:59:36 +02:00

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