# Kubernetes

## Kubernetes

### Tools

#### [Kind](https://github.com/kubernetes-sigs/kind)

#### [kubectx/kubens](https://github.com/ahmetb/kubectx)

Super useful for easily switching contexts and namespaces

#### [Stern](https://github.com/wercker/stern)

Great for live tailing logs from multiple pods/containers

#### [kube-ps1](https://github.com/jonmosco/kube-ps1)

Shows some nice Kubernetes output in the CLI

#### [keda](https://keda.sh/)

#### [chart-testing](https://github.com/helm/chart-testing)

The `ct` command is great for testing Helm charts

### Commands

**Get pods**

```bash
kubectl get po
```

**Create Service Account**

**ClusterRoleBinding**

**Rollout Restart**

`kubectl rollout restart -n $namespace deployment/$deployment-name`

**Running a one-off command against a pod**

The below runs `env` within the pod without having the directly exec into it

```
kubectl exec -it my-pod-name -- env
```

**Tail logs**

Use stern for this!

**Init Containers**

To view logs from the init container, use the `-c` flag

```
kubectl logs <pod-name> -c <init-container>
```

### Resources

#### [External Secrets](https://github.com/external-secrets/kubernetes-external-secrets)

Used to create `Secret` resources without needing to store credentials in source control!

AWS system manager (Parameter )

**Basic Setup**

```yaml
apiVersion: "kubernetes-client.io/v1"
kind: ExternalSecret
metadata:
  name: hello-service
spec:
  backendType: systemManager
  data:
    - name: password
      key: /hello-service/password
```

### Namespaces

#### Deleting namespaces

Namespaces can often get stuck in a `Terminating` process despite being completely empty

To fully delete the namespace, run the following

```bash
NAMESPACE=linkerd
kubectl get namespace $NAMESPACE -o json > $NAMESPACE.json
sed -i -e 's/"kubernetes"//' $NAMESPACE.json
kubectl replace --raw "/api/v1/namespaces/$NAMESPACE/finalize" -f ./$NAMESPACE.json
```


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