- https://kubernetes.io/docs/tasks/debug/debug-application/ (search: troubleshoot)
Examine the web-consumer deployment, which resides in the web namespace, and its Pods by using:
kubectl get deployment -n web web-consumer
Get more information, including container specifications and labels that the Pods are using, by using:
kubectl describe deployment -n web web-consumer
Look more closely at the Pods to see if both Pods are up and running by using:
kubectl get pods -n web
Get more information about the Pods and evaluate any warning messages that may come up by using:
kubectl describe pod -n web <POD_NAME>
Look at the logs associated with the container busybox by using:
kubectl logs -n web <POD_NAME> -c busybox
Determine what may be going wrong by reading the output from the container logs.
Take a closer look at the pod itself to get the data in the yaml format by using:
kubectl get pod -n web <POD_NAME> -o yaml
Determine which command is causing the errors (in this case, the while true; do curl auth-db; sleep 5; done command).
Take a closer look at the service by using:
kubectl get svc -n web auth-db
Locate where the service is and finding the one other non-default namespace called data:
kubectl get namespaces
Check and find the auth-db service in this namespace, rather than the web namespace:
kubectl get svc -n data
Start resolving the issue by using:
kubectl edit deployment -n web web-consumer
In the spec section, scroll down to find the pod template and locate the while true; do curl auth-db; sleep 5; done command.
Change the command to while true; do curl auth-db.data.svc.cluster.local; sleep 5; done to give the fully qualified domain name of that service. This will allow the web-consumer deployment's Pods to communicate with the service successfully.
Check to ensure that the old pods have terminated and the new pods are running successfully:
kubectl get pods -n web
Check the log of one of the new pods, this time the pod should be able to communicate successfully with the service:
kubectl logs -n web <POD-NAME> -c busybox