## K3S + MetalLB

Install k3s + MetalLB in a cluster with RaspberryPi.

#### Instructions:

1. Edit `/boot/cmdline.txt` file and the configuration at the end of line: `cgroup_memory=1 cgroup_enable=memory`
1. On control node, generate a secret and install k3s:

    ```TOKEN=`python3 -c "import secrets; print(secrets.token_hex(32))"` ```

    ```curl -sfL https://get.k3s.io | sh -s - --write-kubeconfig-mode 644 --disable servicelb --token $TOKEN --bind-address <control_node_ip>```

1. Run the followed command in worker nodes:

    ```curl -sfL https://get.k3s.io | K3S_URL=https://<control_node_ip>:6443 K3S_TOKEN=<token> sh -```

1. When the installation is completed, let's relabel the worker nodes:

    ```kubectl label nodes <node_name> kubernetes.io/role=worker```

1. Now, connect throught ssh with control node and install MetalLB:

    ```kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.13.7/config/manifests/metallb-native.yaml```

1. The followed commands need to be executed in Control Node.

1. Define the IP addresses that will be used by MetalLB, we need to create a config.yml file and apply with kubectl:

    ```touch config.yml```
    ```
    apiVersion: metallb.io/v1beta1
    kind: IPAddressPool
    metadata:
      name: config
      namespace: metallb-system
    spec:
      addresses:
      - <first_node_ip_in_cluster>-<last_node_ip_in_cluster>
    ```
    ```kubectl apply -f config.yml```
    
1. To testing these configurations, let's deploy the a Nginx in the cluster:

    ```touch deployment.yml```

    ```yml
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: nginx
    spec:
      selector:
        matchLabels:
          app: nginx
      replicas: 3
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - name: nginx
            image: nginx:alpine
            ports:
            - containerPort: 80
    ```

    ```touch service.yml```

    ```yml
    apiVersion: v1
    kind: Service
    metadata:
      name: nginx
    spec:
      selector:
        app: nginx
      ports:
        - port: 80
          targetPort: 80
      type: LoadBalancer
    ```
    
    ```kubectl apply -f deployment.yml```  
    ```kubectl apply -f service.yml```

1. To check if the the deployment and services are running as expected, run the followed commands:

    ```kubectl get pods```  
    ```kubectl get services```
    
1. The output will be similar to this one:

    ```bash
    pi@raspberrypi:~/k8s-nginx $ kubectl get pods
    NAME                    READY   STATUS    RESTARTS   AGE
    nginx-965685897-bddf7   1/1     Running   0          19h
    nginx-965685897-cfx4z   1/1     Running   0          19h
    nginx-965685897-n274m   1/1     Running   0          19h
    nginx-965685897-wxblb   1/1     Running   0          19h
    nginx-965685897-t2zhr   1/1     Running   0          19h
    pi@raspberrypi:~/k8s-nginx $ kubectl get services
    NAME         TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
    kubernetes   ClusterIP      10.43.0.1       <none>        443/TCP        19h
    nginx        LoadBalancer   10.43.134.193   10.0.0.10     80:30341/TCP   19h
    ```
    
1. The nginx service will be avaliable on External IP 10.0.0.10, to access in your browser.

1. If you need to remove the k3s installation just run the followed commands:

    1. Control Plane:
        
        ```/usr/local/bin/k3s-uninstall.sh```
      
    2. Workers:

        ```/usr/local/bin/k3s-agent-uninstall.sh```


Useful links related to MetalLB configurations:

[Reload IP configuration](https://github.com/metallb/metallb/issues/348)  
[IP Range change workflow](https://github.com/metallb/metallb/issues/308)