Install MetalLB load balancer for Kubernetes

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In this tutorial I will show you how to install Metal LB load balancer running on Kubernetes (k8s).

Parts of the Kubernetes series

Enviroment

kubectl get node
NAME     STATUS   ROLES    EXTERNAL-IP
host-1   Ready    master   203.0.113.1
host-2   Ready    node     203.0.113.2
host-3   Ready    node     203.0.113.3
host-4   Ready    node     203.0.113.4

MetalLB provides a network load-balancer implementation for Kubernetes clusters that do not run on a supported cloud provider, effectively allowing the usage of LoadBalancer Services within ber-metal Installation. Kubernetes does not offer an implementation of network load-balancers (Services of type LoadBalancer) for bare metal clusters. The implementations of Network LB that Kubernetes does ship with are all glue code that calls out to various IaaS platforms (GCP, AWS, Azure…). If you’re not running on a supported IaaS platform (GCP, AWS, Azure…), LoadBalancers will remain in the “pending” state indefinitely when created.

Example image

First we need to apply the MetalLB manifest.

kubectl apply -f https://raw.githubusercontent.com/google/metallb/v0.8.1/manifests/metallb.yaml

Create a metallb-configmap.yaml file and modify your IP range accordingly.

cat < EOF > metallb-config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: my-ip-space
      protocol: layer2
      addresses:
      - 203.0.113.2-203.0.113.4    
EOF

kubectl apply -f metallb-config.yaml
kubectl get pods -n metallb-system

Exposing a service through the load balancer

cat <EOF>> nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  type: LoadBalancer
  selector:
    app: nginx
  ports:
  - port: 80
    name: http
EOF

kubectl apply -f nginx-deployment.yaml
kubectl get svc
NAME           TYPE           CLUSTER-IP       EXTERNAL-IP    PORT(S)        AGE
nginx          LoadBalancer   10.109.51.83     203.0.113.2    80:30452/TCP   5m