[docker-29.x backport] libnet: create DNS records on sbJoin (if not agent node)#51515
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[docker-29.x backport] libnet: create DNS records on sbJoin (if not agent node)#51515
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Commit a8b9eff removed a call to Network.updateSvcRecord from Network.createEndpoint on the grounds that: > all callers of Network.createEndpoint follow up with an Endpoint.Join, > which also sets up the DNS entry. However, the original call in Network.createEndpoint was gated by: ``` if !n.getController().isSwarmNode() || n.Scope() != scope.Swarm || !n.driverIsMultihost() { n.updateSvcRecord(context.WithoutCancel(ctx), ep, true) } ``` whereas the call in Endpoint.sbJoin() (invoked by Endpoint.Join()) is gated by: ``` if !n.getController().isAgent() { if !n.getController().isSwarmNode() || n.Scope() != scope.Swarm || !n.driverIsMultihost() { n.updateSvcRecord(context.WithoutCancel(ctx), ep, true) } } ``` As a result, once a node has joined a Swarm cluster, no DNS entries are created for non swarm-scoped networks. Change the condition used by `sbJoin` to match the original condition used in `createEndpoint`. Signed-off-by: Albin Kerouanton <albin.kerouanton@docker.com> (cherry picked from commit 2e41476) Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Previous commit reverted a faulty change that broke DNS resolution for non swarm-scoped networks once a node has joined a Swarm cluster. This commit adds an integration test to verify that we don't break DNS resolution again. Signed-off-by: Albin Kerouanton <albin.kerouanton@docker.com> (cherry picked from commit 47bd247) Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
If the DNS name still resolves to an IP address, and that address is assigned to a running container, the ping command will run indefinitely and the test suite will time out for 10 mins. This is confusing, as it looks like a daemon hang, or a test suite hang, whereas it's just a test failure. Add '-c1' to ping to make it return immediately. Signed-off-by: Albin Kerouanton <albin.kerouanton@docker.com> (cherry picked from commit 53ea70e) Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
vvoland
marked this pull request as ready for review
November 13, 2025 19:50
robmry
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Nov 13, 2025
corhere
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Nov 13, 2025
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backport: libnet: create DNS records on sbJoin (if not agent node) #51495
Fixes DNS resolution broken after
docker swarm init(29.0.0) #51491Related to Release IPv6 address if IPv6 is disabled on an interface #48971
- What I did
Commit a8b9eff removed a call to Network.updateSvcRecord from Network.createEndpoint on the grounds that:
However, the original call in Network.createEndpoint was gated by:
whereas the call in Endpoint.sbJoin() (invoked by Endpoint.Join()) is gated by:
As a result, once a node has joined a Swarm cluster, no DNS entries are created for non swarm-scoped networks.
Change the condition used by
sbJointo match the original condition used increateEndpoint, and add an integration test.- Human readable description for the release notes