Aspsk/fix dns resolution on kind #24713
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The So removing the test commit, everything looks fine |
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We are using our Kind provisioning script to create K8s clusters when testing in the CI. Recently, we discovered that on some kernels a default DNS resolver, which is dockerd, is troublesome for the BPF host routing, which we want to test in the CI (#23283). Fix this by patching the coredns configmap after creating a kind cluster to point to the 8.8.8.8 resolver. Alternative fixes (may still be applied later): * Pass a custom /etc/resolv.conf to kubelet via --resolv-conf in the Kind / kubeadm config. * Override /etc/resolv.conf of Kind nodes after creating a cluster (no race condition, as CoreDNS pods won't be started, as a CNI is not ready). * Patch Kind to allow users to specify custom DNS entries (i.e., docker run --dns="1.1.1.1,8.8.8.8"). Fixes: #23283 Fixes: #23330 Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
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sahid
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lmb
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| # This is required because in case of BPF Host Routing we bypass iptables thus | ||
| # breaking DNS. See https://github.com/cilium/cilium/issues/23330 | ||
| NewCoreFile=$(kubectl get cm -n kube-system coredns -o jsonpath='{.data.Corefile}' | sed 's,forward . /etc/resolv.conf,forward . 8.8.8.8,' | sed -z 's/\n/\\n/g') | ||
| kubectl patch configmap/coredns -n kube-system --type merge -p '{"data":{"Corefile": "'"$NewCoreFile"'"}}' |
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Is this command synchronous? If not, is there a way to wait for the change to be done?
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What do you mean exactly? I think that after this command is finished, the coredns CM will not expose the old value. The coredns or any other non-hostns pods are not running at this stage yet
lmb
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Have you had a successful run with https://github.com/cilium/cilium/blob/master/.github/workflows/conformance-datapath.yaml#L23 uncommented? |
Affirmative (the only thing which failed was net-next on geneve/dsr, as is listed above: #24713 (comment)) |
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Only bce8d9e needs to be backported to v1.13. |
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Patch coredns configmap to bypass docker DNS resolver in kind and use 8.8.8.8. Re-enable masquerading and fast routing for the EGW test.
Fixes: #23283
Fixes: #23330