Kind: Kind fails to creates pods when IPV6 is disabled in the host

Created on 18 Jun 2019 · 3Comments · Source: kubernetes-sigs/kind

What happened:

Kind fails to creates pods when IPV6 is disabled in the UBUNTU 18.04 kernel of the host system.

GRUB_CMDLINE_LINUX="ipv6.disable=1"

kubectl -n kube-system describe pod/coredns-... reports the following event.

 Warning  FailedCreatePodSandBox  53m                 kubelet, kind-control-plane  Failed create pod sandbox: rpc error: code = Unknown desc = failed to setup network for sandbox "4353e3f9fddbe3c1ac60d98576157e037560cb14dc99c76e6458ed9882ebb96f": failed to add route '{:: 00000000000000000000000000000000} via <nil> dev eth0': operation not supported

HACK Removing the {"dst": "::/0"} route request in the /etc/cni/net.d/10-kindnet.conflist file solves the issue.

...
        "routes": [
          {"dst": "0.0.0.0/0"},
          {"dst": "::/0"}
        ],
...

What you expected to happen

When IPV6 is not available in the host system, then kind create cluster should manage CNI configuration accordingly.

Actually the CNI configuration is hardcoded in kind/pkg/build/node/cni.go file.

How to reproduce it (as minimally and precisely as possible):

Disable IPV6 support before to create a cluster.

Anything else we need to know?:

WORKAROUND: After the cluster is created connect into the docker worker node with the following command

docker exec -it kind-control-plane bash

and fix the /etc/cni/net.d/10-kindnet.conflist as explained previously.

Environment:

kind version: v.0.3.0
Kubernetes version:
Client Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.3", GitCommit:"5e53fd6bc17c0dec8434817e69b04a25d8ae0ff0", GitTreeState:"clean", BuildDate:"2019-06-06T01:44:30Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.2", GitCommit:"66049e3b21efe110454d67df4fa62b08ea79a19b", GitTreeState:"clean", BuildDate:"2019-05-17T00:58:35Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
Docker version:
Containers: 1
Running: 1
Paused: 0
Stopped: 0
Images: 2
Server Version: 18.09.6
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: bb71b10fd8f58240ca47fbb579b9d1028eea7c84
runc version: 2b18fe1d885ee5083ef9f0838fee39b62d653e30
init version: fec3683
Security Options:
apparmor
seccomp
Profile: default
Kernel Version: 4.15.0-51-generic
Operating System: Ubuntu 18.04.2 LTS
OSType: linux
Architecture: x86_64
CPUs: 8
Total Memory: 23.21GiB
Name: sarah
ID: BKXJ:7PP4:KY33:TJT6:CUA4:SUO5:6UXT:YWMA:WUZQ:HKX5:TWJ5:VQ2J
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
HTTP Proxy: http://xxxxx:[email protected]:3128
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine
OS (e.g. from /etc/os-release):
NAME="Ubuntu"
VERSION="18.04.2 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.2 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic