k3s with MetalLB - Sketch

instructions.md

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

2. 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>

3. Run the followed command in worker nodes:

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

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

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

5. 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

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

7. 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

8. To testing these configurations, let's deploy the a Nginx in the cluster:

   touch deployment.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

   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

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

   kubectl get pods
kubectl get services

10. The output will be similar to this one:

    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

11. The nginx service will be avaliable on External IP 10.0.0.10, to access in your browser.

12. 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
IP Range change workflow