> For the complete documentation index, see [llms.txt](https://lauradang.gitbook.io/notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lauradang.gitbook.io/notes/devops/kubernetes/kubernetes-commands.md).

# Kubernetes Commands

## Debugging

<https://kubernetes.io/docs/reference/kubectl/cheatsheet/#kubectl-output-verbosity-and-debugging>

* `--v=9` is good for seeing values, put into JSON formatter

## Get logs for pod

```bash
$ kubectl logs <pod_name>
```

## Get logs for ingress controller

```bash
$ kubectl logs -n kube-system $(kubectl get po -n kube-system | egrep -o 'alb-ingress[a-zA-Z0-9-]+')
```

## Spinning up the instances

```bash
$ kubectl run --replicas=1000 web-server # deploys an application on the cluster 1000 times
```

## Scaling the instances

```bash
$ kubectl run --replicas=1000 web-server
$ kubectl scale --replaces=2000 web-server # scales up the current webserver to 2000 instances
```

## Updating the instances

```bash
# Updates all instances to the given image
$ kubectl rolling-update web-server --image=web-server:2
```

## Rollback

```bash
# If something goes wrong in the updates, we can always roll back all the instances
$ kubectl rolling-update web-server --rollback
```

## View Information on the Cluster

```bash
$ kubectl cluster-info
```

## See nodes in cluster

```bash
$ kubectl get nodes
```

## List pods

```bash
$ kubectl get pods
```

## Describe pods (Troubleshooting)

```bash
$ kubectl describe pod <pod_name>
```

## Exec into bash

```bash
$ kubectl exec -it <pod_name> -c <container_name> -- /bin/bash
```

## Delete pods by pattern

```bash
kubectl get pods -n default --no-headers=true | awk '/<word>/{print $1}'| xargs  kubectl delete -n default pod
```