Usage
Authentication
Deployments
Scale Down / Up
This has to be done through the deployment in the helm chart. Another way to do it is to scale down
num=0
kubectl scale --replicas=${num} -n <namespace> deployment/<deploymentname>
Pods
List Running Pods
kubectl get pods -A
Kubernetes lets you divide your cluster into namespaces. Each namespace can have its own set of resources. The above command lists all running pods on every cluster. Pods in the kube-system namespace belong to Kubernetes and helps it function.
Describe Pods
kubectl describe pods <podname>
“SSH”
To connect to the application look at the namespaces:
kubectl get pods -A
kubectl exec -it -n <namespace> <pod> -c <container> -- bash
Logs
kubectl get pods -A
kubectl logs -f -n <namespace> <pod> -c <container>
This lets you view the logs of the running pod. The container running on the pod should be configured to output logs to STDOUT/STDERR.
Restart a Pod
If you pod is not responding or needs a restart the way to do it is to use the following command. This will delete the pod and replace it with a new pod if it is a part of a deployment.
kubectl delete pod <pod-name>
Pod Issues
A pod can have various different errors. The common ones are:
- OOMError: The pod or underlying node ran out of memory and killed the pod.
- CrashLoopBackup: The application itself has an issue, use
kubectl logs -f <pod>to find out why - ImageNotFound: The docker image for the pod can't be found.