yurt-tunnel

** 1. How to locate the cause of kubectl execcommand execution failure **

please check according to the process in the figure below.

• if exec request info can't be found in logs of kube-apiserver, please set log level of kube-apiserver to 3(--v=3)
• make sure kube-apiserver use yurt-tunnel-dns pod to resolve hostname. please reference the tutorial of kube-apiserver adjustment here: https://openyurt.io/docs/installation/openyurt-prepare#3-kube-apiserver-adjustment

** 2. kubectl logs edge node error：error: Error from server (ServiceUnavailable): the server is currently unable to handle the request ( pods/log xxx)**

For more details about this problem, you can refer to issue 984. Please make sure that you are using the latest yurt-tunnel-server/agent image (the latest tag of image is confusing, please check the created time).

** 3. kubectl logs edge node error：error: You must be logged in to the server (the server has asked for the client to provide credentials ( pods/log xxx))**

For more details about this problem, you can refer to issue 984. This is most likely to be an issue caused by outdated tunnel server certificate. You can clean up the tunnel server certificate and redeploy yurt-tunnel-server.

rm -rf /var/lib/yurttunnel-server/pki
kubectl delete pod yurt-tunnel-server-xxxxxx -n kube-system

** 4. kubectl exec error: unable to upgrade connection: fail to setup the tunnel: fail to setup TLS handshake through the Tunnel**

kubectl port-forward may also fail the following similar error.

root@control-plane:~# kubectl port-forward <...>
error: unable to upgrade connection: fail to setup the tunnel: fail to setup TLS handshake through the Tunnel: write unix @->/tmp/interceptor-proxier.sock: write: broken pipe

Fundamentally this problem should be observed because yurt-tunnel-server/agent connection cannot be established.

It is likely that this problem may happen since yurt-tunnel-agent is not deployed to the corresponding edge nodes.

In that case, it is highly recommended to go through Setup openyurt components to make sure yurt-tunnel-server/agent pods are deployed to appropriate cloud and edge nodes.

If this problem can be observed by requesting kubectl exec/port-forward to cloud node which does not require yurt-tunnel-server/agent to access the kubelet running on the node, issue may be related to network setting /etc/hosts.

If /etc/hosts includes any IP addresses with the same hostname registered to Kubernetes / OpenYurt cluster, it might lead the request to be over yurt-tunnel-server/agent.

This request will eventually fail with the error message, since there will be no yurt-tunnel-agent running on cloud nodes.

In this case, those unrelated IP addresses and hostname would need to be commented out.

For more details, please refer to issue 1024.