LAN wide accessible IP addresses for applications deployed in local Kubernetes cluster

Create an application in kubernetes cluster which is accessible from entire lan⌗

If you’re running a local kubernetes cluster like k3d, then most probably you won’t be able to access the application which is running inside the kubernetes cluster in your local network (unless you’re running behind the ingress with each application separate path).

In this tutorial, we’ll make a single node kubernetes cluster and install one nginx web server which will be accessible from the entire LAN.

Code⌗

Create kuernetes cluster

k3d cluster create --k3s-server-arg --no-deploy --k3s-server-arg traefik --network host --k3s-server-arg --no-deploy --k3s-server-arg servicelb  --api-port ${2:-16433} --no-hostip

Wait for your cluster to be up
```
kubectl cluster-info
```

Install metallb.

Metallb is a serivce, which will talk to your local router, to publish the ip address from your given address pool(more on this on the config part). Metallb can use layer2/BGP protocols to publish the ip address.

Long story short, you’ll get an ip address in your LAN, like you’ve another device connected.

Installing metallb in kubernetes so that it can provide ip addresses

kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.5/manifests/namespace.yaml
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.5/manifests/metallb.yaml
# On first install only
kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"

Configure ip range

Note: This should be a valid ip range from your LAN. For example, if your network subnet is 192.168.0.0/24 (ie, 192.168.0.1-255), reserve the last 20 ips(192.168.0.200-220).

kubectl apply -f - << EOF
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
      - 192.168.1.200-192.168.1.220
EOF

Deploying a sample application

kubectl apply -f - << EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-metallb
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx-metallb
  template:
    metadata:
      labels:
        app: nginx-metallb
    spec:
      containers:
      - name: name
        image: nginx
        resources:
          requests:
            cpu: 100m
            memory: 200Mi
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-metallb
  namespace: default
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 80
  selector:
    app: nginx-metallb
EOF

Access the application ip address. Now you can use this ip address from entire lan to access the application.
```
kubectl get svc nginx --template="{{range .status.loadBalancer.ingress}}{{.ip}}{{end}}"
```