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Oracle Linux: Kubernetes Services Fail if IPV6 is Disabled. (Doc ID 2404109.1)

Last updated on AUGUST 04, 2018

Applies to:

Linux OS - Version Oracle Linux 7.2 with Unbreakable Enterprise Kerne [4.1.12] and later
Linux x86-64

Symptoms

Kubernetes pods related to flannel network, dns will not work when ipv6 is disabled, we can see following errors in the /varlog/messages.

dockerd service will also throw errors when tries to disable ipv6 forwarding.

 

Apr 4 10:58:42 xx-xxxx kubelet: E0404 10:58:42.560593 19471 cni.go:259] Error adding network: open /proc/sys/net/ipv6/conf/eth0/accept_dad: no such file or directory
Apr 4 10:58:42 xx-xxxx kubelet: E0404 10:58:42.561006 19471 cni.go:227] Error while adding to cni network: open /proc/sys/net/ipv6/conf/eth0/accept_dad: no such file or directory
Apr 4 10:58:42 xx-xxxx kubelet: E0404 10:58:42.678479 19471 remote_runtime.go:92] RunPodSandbox from runtime service failed: rpc error: code = Unknown desc = NetworkPlugin cni failed to set up pod "kube-dns-855949bbf-k2mhf_kube-system" network: open /proc/sys/net/ipv6/conf/eth0/accept_dad: no such file or directory

Apr 4 08:35:34 xx-xxxxX kubelet: W0404 08:35:34.345108 3642 pod_container_deletor.go:77] Container "d51cd6ed83956c7c6407b595199f41414f6016cb1eab094b6dcd82e00edc6365" not found in pod's containers
Apr 4 08:35:34 xx-xxxxX kubelet: W0404 08:35:34.352590 3642 pod_container_deletor.go:77] Container "daf3e95f93eb486d7116a79c8dfd3c4bd9f30df649018812c32cd5d7c7c56914" not found in pod's containers
Apr 4 08:35:34 xx-xxxxX kernel: IPVS: Creating netns size=2144 id=102204
Apr 4 08:35:34 xx-xxxxX kernel: IPVS: Creating netns size=2144 id=102205
Apr 4 08:35:34 xx-xxxxX dockerd: time="2018-04-04T08:35:34Z" level=error msg="failed to disable IPv6 forwarding for container's interface all: open /proc/sys/net/ipv6/conf/all/disable_ipv6: no such file or directory"
Apr 4 08:35:34 xx-xxxxX dockerd: time="2018-04-04T08:35:34.861263985Z" level=warning msg="Failed to disable IPv6 on all interfaces on network namespace \"/var/run/docker/netns/db355606448f\": reexec to set IPv6 failed: exit status 4"
Apr 4 08:35:34 xx-xxxxx dockerd: time="2018-04-04T08:35:34Z" level=error msg="failed to disable IPv6 forwarding for container's interface all: open /proc/sys/net/ipv6/conf/all/disable_ipv6: no such file or directory"
Apr 4 08:35:34 xx-xxxxx dockerd: time="2018-04-04T08:35:34.925978603Z" level=warning msg="Failed to disable IPv6 on all interfaces on network namespace \"/var/run/docker/netns/f5fb36614925\": reexec to set IPv6 failed: exit status 4"
Apr 4 08:35:34 xx-xxxxx kernel: device vethe4b3685b entered promiscuous mode
Apr 4 08:35:34 xx-xxxxx kernel: cni0: port 1(vethe4b3685b) entered forwarding state
Apr 4 08:35:34 xx-xxxxx kernel: cni0: port 1(vethe4b3685b) entered forwarding state
Apr 4 08:35:34 xx-xxxxx kubelet: E0404 08:35:34.978746 3642 cni.go:259] Error adding network: failed to allocate for range 0: no IP addresses available in range set: 10.244.0.1-10.244.0.254
Apr 4 08:35:34 xx-xxxxx kubelet: E0404 08:35:34.979232 3642 cni.go:227] Error while adding to cni network: failed to allocate for range 0: no IP addresses available in range set: 10.244.0.1-10.244.0.254
Apr 4 08:35:35 xx-xxxxx kernel: device veth5b3ea64b entered promiscuous mode
Apr 4 08:35:35 xx-xxxxx kernel: cni0: port 2(veth5b3ea64b) entered forwarding state
Apr 4 08:35:35 xx-xxxxx kernel: cni0: port 2(veth5b3ea64b) entered forwarding state
Apr 4 08:35:35 xx-xxxxx kubelet: E0404 08:35:35.062373 3642 cni.go:259] Error adding network: failed to allocate for range 0: no IP addresses available in range set: 10.244.0.1-10.244.0.254
Apr 4 08:35:35 xx-xxxxx kubelet: E0404 08:35:35.062439 3642 cni.go:227] Error while adding to cni network: failed to allocate for range 0: no IP addresses available in range set: 10.244.0.1-10.244.0.254
Apr 4 08:35:35 xx-xxxxx kernel: cni0: port 1(vethe4b3685b) entered disabled state
Apr 4 08:35:35 xx-xxxxx kernel: device vethe4b3685b left promiscuous mode


 

Changes

New setup with kubernetes 1.9.1 on OL 7.4, no changes to the kubernetes environment.

Cause

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