Investigate docker v27 ipv6 changes

[BenTheElder]

See:

https://docs.docker.com/engine/release-notes/27.0/#ipv6

https://kubernetes.slack.com/archives/CEKK1KTN2/p1719537867758879

kubernetes/test-infra#32863 (comment)

We need to figure out how we want to handle these in Kubernetes's CI and in kind.

/assign @aojea

[aojea]

Did we see any issues yet?

we have this weird problem here kubernetes-sigs/kube-network-policies#47 (comment) , but I do not know if is related

[BenTheElder]

Did we see any issues yet?

Yes.

You can see that just creating the network now flakes in pull-kind-test job, since we updated to docker v27 in CI earlier: kubernetes/test-infra#32863 (comment)

[BenTheElder]

Example failure: #648 (comment)

https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-sigs_kind/648/pull-kind-test/1807905535295492096

A user also reported issues with their own environment and docker v27 in the slack link above.

[BenTheElder]

=== FAIL: pkg/cluster/internal/providers/docker TestIntegrationEnsureNetworkConcurrent (1.45s)
network_integration_test.go:60: error creating network: command "docker network create -d=bridge -o com.docker.network.bridge.enable_ip_masquerade=true -o com.docker.network.driver.mtu=1500 --ipv6 --subnet fc00:3051:9942:af9f::/64 integration-test-ensure-kind-network" failed with error: exit status 1
network_integration_test.go:63: "Error response from daemon: Failed to Setup IP tables: Unable to enable NAT rule: (iptables failed: ip6tables --wait -t nat -I POSTROUTING -s fc00:3051:9942:af9f::/64 ! -o br-4e53c7863d0d -j MASQUERADE: modprobe: FATAL: Module ip6_tables not found in directory /lib/modules/5.15.0-1054-gke\nip6tables v1.8.9 (legacy): can't initialize ip6tables table `nat': Table does not exist (do you need to insmod?)\nPerhaps ip6tables or your kernel needs to be upgraded.\n (exit status 3))\n"
network_integration_test.go:65:

[aojea]

Commented in kubernetes/test-infra#32863 (comment)

[BenTheElder]

working on fix in:
kubernetes/test-infra#32890
kubernetes/test-infra#32891
+ triggered an early re-run of autobump job following those and then merging:
kubernetes/test-infra#32881

[BenTheElder]

OK, I think this is mitigated for Kubernetes CI now, after also kubernetes/test-infra#32895

We should still look into the behavior changes more and probably clean up the dind iptables stuff.

[BenTheElder]

Another variant, possibly, https://kubernetes.slack.com/archives/CEKK1KTN2/p1723750263635729