While joining worked node to control node all on GCP facing error while running join command

shrikiec

In exercise 3.2 ,the 7th instruction kubeadm join ....
Though gave correctly token and hash

I0502 00:06:17.376217   20381 checks.go:132] validating if the "kubelet" service is enabled and active
I0502 00:06:17.389317   20381 checks.go:205] validating availability of port 10250
I0502 00:06:17.389610   20381 checks.go:282] validating the existence of file /etc/kubernetes/pki/ca.crt
        [WARNING FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
I0502 00:06:17.389688   20381 checks.go:432] validating if the connectivity type is via proxy or direct
[preflight] Some fatal errors occurred:
        [ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
error execution phase preflight
k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow.(*Runner).Run.func1
        /workspace/src/k8s.io/kubernetes/_output/dockerized/go/src/k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow/runner.go:235

chrispokorni

Hi @shrikiec,

The errors above are typically seen on systems where the kubeadm join command was run several times in a row.

Please run kubeadm reset on the worker node as root, then attempt once the kubeadm join command on the worker node as root (or with sudo), and capture if/any errors are produced then, to be able to troubleshoot any possible issues. Keep in mind, however, that only "errors" should be of concern, "warnings" are safe to disregard.

Regards,
-Chris

shrikiec

oot@cp-worked:~# kubeadm join --token xxxx k8scp:6443 --discovery-token-ca-cert-hash sha256:xxxx
[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 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
root@cp-worked:~#

shrikiec

Thanks had to add flag for "--cgroup-driver=cgroupfs"

From stack driver : To solve it, first find Docker cgroup:

docker info | grep Cgroup

The result of the above command would be something like this:

Cgroup Driver: cgroupfs
Cgroup Version: 1
Then, update kubelet args (KUBELET_KUBECONFIG_ARGS) in /etc/systemd/system/kubelet.service.d/10-kubeadm.conf and add a --cgroup-driver flag corresponsing to docker cgroup (in this case cgroupfs).

My config file looks like this after the modification:
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/e`tc/kubernetes/kubelet.conf --cgroup-driver=cgroupfs"

Finally, run kubeadm reset and then kubeadm init.