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Task Summary

SSH into node: cka000059

Cluster was migrated to a new machine

It uses an external etcd server

Identify and fix misconfigured components

Bring the cluster back to a healthy state

Step-by-Step Solution

Step 1: SSH into the correct host

ssh cka000059

Step 2: Check the cluster status

Run:

kubectl get nodes

If it fails, the kubelet or kube-apiserver is likely broken.

Check kubelet status:

sudo systemctl status kubelet

Also, check pod statuses in the control plane:

sudo crictl ps -a | grep kube

or:

docker ps -a | grep kube

Look especially for failures in kube-apiserver or kube-controller-manager.

Step 3: Inspect the kube-apiserver manifest

Since this is a kubeadm-based cluster, manifests are in:

ls /etc/kubernetes/manifests

Open kube-apiserver.yaml:

bash

CopyEdit

sudo nano /etc/kubernetes/manifests/kube-apiserver.yaml

Look for the --etcd-servers= flag. If the external etcd endpoint has changed (likely, due to migration), this needs to be fixed.

Example of incorrect configuration:

--etcd-servers=https://192.168.1.100:2379

If the IP has changed, update it to the correct IP or hostname of the external etcd server.

Also ensure the correct client certificate and key paths are still valid:

--etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt

--etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt

--etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key

If the files are missing or the path is wrong due to migration, correct those as well.

Step 4: Save and exit, and let static pod restart

Static pod changes will be picked up automatically by the kubelet (watch for /etc/kubernetes/manifests changes).

Check again:

docker ps | grep kube-apiserver

# or

crictl ps | grep kube-apiserver

Step 5: Confirm API is healthy

Once kube-apiserver is up, try:

kubectl get componentstatuses

kubectl get nodes

If these commands work and return valid statuses, the control plane is functional again.

Step 6: Check controller-manager and scheduler (optional)

If still broken, check the other static pods in /etc/kubernetes/manifests/ and correct paths if necessary.

Also verify that /etc/kubernetes/kubelet.conf and /etc/kubernetes/admin.conf are present and valid.

Command Summary

ssh cka000059

# Check system and kubelet

sudo systemctl status kubelet

docker ps -a | grep kube # or crictl ps -a | grep kube

# Check manifests

ls /etc/kubernetes/manifests

sudo nano /etc/kubernetes/manifests/kube-apiserver.yaml

# Fix --etcd-servers and certificate paths if needed

# Watch pods restart and confirm:

kubectl get nodes

kubectl get componentstatuses