# Cheat Sheet

## Install

### Latest

```
snap install microk8s --classic
```

### Specific version

```
snap install microk8s --classic --channel=1.17/stable
```

### Set group

```
sudo usermod -a -G microk8s $USER
```

Logout from your workstation session and login again.

## Useful commands

### Get kubeconfig

```
microk8s.config > $HOME/.kube/config
```

### Reset cluster

```
microk8s reset --destroy-storage
```

### References

<https://microk8s.io/docs/commands>

## Built-in Registry

### Push

Pushing to this insecure registry may fail in some versions of Docker unless the daemon is explicitly configured to trust this registry. To address this we need to edit /etc/docker/daemon.json and add:

{% code title="/etc/docker/daemon.json" %}

```
{
  "insecure-registries" : ["localhost:32000"]
}
```

{% endcode %}

Then restart docker.

```
sudo systemctl restart docker
```

Enable registry, build and push image.

```
microk8s enable registry #20Gi registry
#microk8s enable registry:size=40Gi

# Build image
docker build . -t localhost:32000/myimage:registry

# Or tag an existing image
#docker tag 1fe3d8f47868 localhost:32000/myimage:registry

docker push localhost:32000/myimage:registry
```

Deploy it.

```
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  namespace: myapp
  labels:
    app: myapp
spec:
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: localhost:32000/myimage:registry
        imagePullPolicy: Always
        ports:
        - containerPort: 8000
```

### Remove

Run on your workstation:

```bash
registry=localhost:32000
repositories=$(curl ${registry}/v2/_catalog)
for repo in $(echo "${repositories}" | jq -r '.repositories[]'); do
  echo $repo
  tags=$(curl -sSL "http://${registry}/v2/${repo}/tags/list" | jq -r '.tags[]')
  for tag in $tags; do
    echo $tag
    curl -v -sSL -X DELETE "http://${registry}/v2/${repo}/manifests/$(
      curl -sSL -I \
          -H "Accept: application/vnd.docker.distribution.manifest.v2+json" \
          "http://${registry}/v2/${repo}/manifests/$tag" \
      | awk '$1 == "Docker-Content-Digest:" { print $2 }' \
      | tr -d $'\r' \
    )"
  done
done
```

Then run:

```bash
registry_pod=$(kubectl --namespace="container-registry" get pods --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
kubectl exec --namespace="container-registry" $registry_pod /bin/registry garbage-collect /etc/docker/registry/config.yml
```

## Local private registry

Allow insecure registry:

{% code title="/etc/docker/daemon.json" %}

```
{
  "insecure-registries" : ["172.17.0.1:5001"]
}

```

{% endcode %}

Restart docker.

```
sudo systemctl restart docker
```

Stop `microk8s`, backup and edit config file.

```
microk8s stop
sudo cp /var/snap/microk8s/current/args/containerd-template.toml /var/snap/microk8s/current/args/containerd-template.toml-BKP
nano /var/snap/microk8s/current/args/containerd-template.toml
```

Add the following section.

```
...
  [plugins."io.containerd.grpc.v1.cri".registry]
...
    [plugins."io.containerd.grpc.v1.cri".registry.mirrors]
...
      [plugins."io.containerd.grpc.v1.cri".registry.mirrors."172.17.0.1:5001"]
        endpoint = ["http://172.17.0.1:5001"]
```

Start `microk8s`.

```
microk8s start
```

Start local registry.

```
docker run -it --rm \
  -e REGISTRY_HTTP_ADDR=0.0.0.0:5001 \
  -p 5001:5001 \
  --name local-registry \
  registry:2
```

Tag and push image.

```
docker tag ubuntu:18.04 172.17.0.1:5001/my-ubuntu:0.0.1
docker push 172.17.0.1:5001/my-ubuntu:0.0.1
curl 172.17.0.1:5001/v2/_catalog
```

Test it.

```
microk8s kubectl run -it --rm tmp --image=172.17.0.1:5001/my-ubuntu:0.0.1
```

### References

<https://microk8s.io/docs/registry-private>


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