[K8S] Kubernetes 설치시 오류 조치

[K8S] ## K8S 설치시 Trouble Shooting

- kubeadm init 했는데 다음과 같이 나오는 경우

[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.

Unfortunately, an error has occurred:
timed out waiting for the condition
This error is likely caused by:
- The kubelet is not running
- The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)
If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
- 'systemctl status kubelet'
- 'journalctl -xeu kubelet'

Additionally, a control plane component may have crashed or exited when started by the container runtime.
To troubleshoot, list all containers using your preferred container runtimes CLI, e.g. docker.
Here is one example how you may list all Kubernetes containers running in docker:
- 'docker ps -a | grep kube | grep -v pause'
Once you have found the failing container, you can inspect its logs with:
- 'docker logs CONTAINERID'
error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster

 

1. docker Cgroup 이 systemd 로 설정되어있을 경우

/etc/docker/daemon.json 파일에 아래 문구 추가한다.

{
	"exec-opts": ["native.cgroupdriver=systemd"]
}

그리고
systemctl daemon-reload
systemctl restart docker

2. 로그 확인

- 'journalctl -xeu kubelet' 

이 명령어를 실행 하면 아래와 같이 로그가 남았다. 

Apr 30 22:19:38 master kubelet: W0430 22:19:38.226441    2372 cni.go:157] Unable to update cni config: No networks found in /etc/cni/net.d
Apr 30 22:19:38 master kubelet: E0430 22:19:38.226587    2372 kubelet.go:2067] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized

 

내 경우에는 위에 2.  /env/environment 설정 에 보면 **no_proxy** 항목에 현재 K8S 가 설치된 Machine 의 IP 를 추가했더니 해결이 되었다.

- kubeadm join 했는데 다음과 같이 나올 경우

[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
    [ERROR Port-10250]: Port 10250 is in use
    [ERROR FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

    VM 에서 다음과 같이 kubeadm join 을 했는데 에러가 났을경우 (node가 2개인데 2번째 노드 구성시)

    kubeadm reset 을 한번 실행하고 다시 join 명령어를 실행해준다.