Kubernetes - Installing Metallb

By default, kubernetes does not come with a loadbalancer which would not restrict you to using only ports 30000-32767 to expose services. The easiest way go being able deploy services on port 80 or 443 without going through a reverse proxy is a project called metallb.

The installation is fairly simple. First, apply the two provided manifests. I'm going to use version 0.12.1

 [archy@kube01 ~]$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.12.1/manifests/namespace.yaml  
 [archy@kube01 ~]$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.12.1/manifests/metallb.yaml  

Metallb requires a configmap to work. I'm going to use layer2 and give the controller a complete subnet:

 [archy@kube01 ~]$ vim /var/tmp/metallb-config.yml  

 ---  
 apiVersion: v1  
 kind: ConfigMap  
 metadata:  
   namespace: metallb-system  
   name: config  
 data:  
   config: |  
     address-pools:  
       - name: default  
         protocol: layer2  
         addresses:  
           - 172.31.19.0/24  

The full example config with comments is available here. Now apply the configmap and your loadbalancer should be ready.

 [archy@kube01 ~]$ kubectl apply -f /var/tmp/metallb-config.yml  

Here's an example snippet for a service of type 'LoadBalancer':

 ---  
 apiVersion: v1  
 kind: Service  
 metadata:  
   name: my-webapp  
 spec:  
   type: LoadBalancer  
   loadBalancerIP: 172.31.11.9  
   ports:  
     - name: my-webapp  
       protocol: TCP  
       port: 443  
       targetPort: 443  
   selector:  
     app: my-webapp  

Feel free to comment and / or suggest a topic.