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Cover image for kind - Setting up Load Balancer using MetalLB - Part 6
Unni P
Unni P

Posted on • Originally published at iamunnip.hashnode.dev

kind - Setting up Load Balancer using MetalLB - Part 6

#opensource #docker #kubernetes #devops

In this article we will look how we can get service type LoadBalancer in our cluster using MetalLB

Introduction

  • MetalLB provides a network load balancer implementation in our cluster

  • Allows you to create Kubernetes services of type LoadBalancer in clusters that don’t run on a cloud provider

  • Sets up MetalLB using layer2 protocol

  • We can send traffic directly to the load balancer’s external IP if the IP space is within the Docker IP space

Usage

  • Create a simple cluster using the below configuration file 
$ cat kind.yml kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 name: dev nodes: - role: control-plane - role: worker - role: worker
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$ kind create cluster --config kind.yml Creating cluster "dev" ... ✓ Ensuring node image (kindest/node:v1.26.3) 🖼 ✓ Preparing nodes 📦 📦 📦 ✓ Writing configuration 📜 ✓ Starting control-plane 🕹️ ✓ Installing CNI 🔌 ✓ Installing StorageClass 💾 ✓ Joining worker nodes 🚜 Set kubectl context to "kind-dev" You can now use your cluster with: kubectl cluster-info --context kind-dev
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$ kubectl get nodes NAME STATUS ROLES AGE VERSION dev-control-plane Ready control-plane 68s v1.26.3 dev-worker Ready <none> 37s v1.26.3 dev-worker2 Ready <none> 37s v1.26.3
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  • Deploy MetalLB using the default manifests and verify the components are up and running 
$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.13.7/config/manifests/metallb-native.yaml namespace/metallb-system created customresourcedefinition.apiextensions.k8s.io/addresspools.metallb.io created customresourcedefinition.apiextensions.k8s.io/bfdprofiles.metallb.io created customresourcedefinition.apiextensions.k8s.io/bgpadvertisements.metallb.io created customresourcedefinition.apiextensions.k8s.io/bgppeers.metallb.io created customresourcedefinition.apiextensions.k8s.io/communities.metallb.io created customresourcedefinition.apiextensions.k8s.io/ipaddresspools.metallb.io created customresourcedefinition.apiextensions.k8s.io/l2advertisements.metallb.io created serviceaccount/controller created serviceaccount/speaker created role.rbac.authorization.k8s.io/controller created role.rbac.authorization.k8s.io/pod-lister created clusterrole.rbac.authorization.k8s.io/metallb-system:controller created clusterrole.rbac.authorization.k8s.io/metallb-system:speaker created rolebinding.rbac.authorization.k8s.io/controller created rolebinding.rbac.authorization.k8s.io/pod-lister created clusterrolebinding.rbac.authorization.k8s.io/metallb-system:controller created clusterrolebinding.rbac.authorization.k8s.io/metallb-system:speaker created secret/webhook-server-cert created service/webhook-service created deployment.apps/controller created daemonset.apps/speaker created validatingwebhookconfiguration.admissionregistration.k8s.io/metallb-webhook-configuration created
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$ kubectl -n metallb-system get pods NAME READY STATUS RESTARTS AGE controller-577b5bdfcc-p7sb5 1/1 Running 0 76s speaker-cgmm4 1/1 Running 0 76s speaker-gwfqr 1/1 Running 0 76s speaker-jk684 1/1 Running 0 76s
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  • As we said earlier in the introduction part, we are using the layer2 protocol of MetalLB. For completing the layer2 configuration, we need to provide MetalLB a range of IP addresses it controls. This IP address range needs to be in the Docker kind network. 
$ docker network inspect -f '{{.IPAM.Config}}' kind [{172.18.0.0/16 172.18.0.1 map[]} {fc00:f853:ccd:e793::/64 fc00:f853:ccd:e793::1 map[]}]
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  • Now we want our load balancer IP range to come from this subclass and we can configure MetalLB to use 172.19.255.200 to 172.19.255.250 by creating IPAddressPool and L2Advertisement resources.

  • Create the necessary MetalLB resources using the below manifest file.

$ cat metallb.yml apiVersion: metallb.io/v1beta1 kind: IPAddressPool metadata: name: kind namespace: metallb-system spec: addresses: - 172.18.255.200-172.18.255.250 --- apiVersion: metallb.io/v1beta1 kind: L2Advertisement metadata: name: kind namespace: metallb-system spec: ipAddressPools: - kind
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$ kubectl apply -f metallb.yml ipaddresspool.metallb.io/kind unchanged l2advertisement.metallb.io/kind created
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$ kubectl -n metallb-system get ipaddresspools NAME AUTO ASSIGN AVOID BUGGY IPS ADDRESSES kind true false ["172.18.255.200-172.18.255.250"] $ kubectl -n metallb-system get l2advertisements NAME IPADDRESSPOOLS IPADDRESSPOOL SELECTORS INTERFACES kind ["kind"]
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Deploy our Application

  • Create an Nginx pod using the below manifest file and verify its status 
$ cat nginx.yml apiVersion: v1 kind: Pod metadata: labels: run: nginx name: nginx spec: containers: - image: nginx name: nginx ports: - containerPort: 80
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$ kubectl apply -f nginx.yml pod/nginx created
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$ kubectl get pods nginx NAME READY STATUS RESTARTS AGE nginx 1/1 Running 0 23s
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  • Expose the Nginx pod as a LoadBalancer service using the below manifest file 
$ cat nginx-loadbalancer.yml apiVersion: v1 kind: Service metadata: labels: run: nginx name: nginx spec: ports: - port: 80 protocol: TCP targetPort: 80 selector: run: nginx type: LoadBalancer
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$ kubectl apply -f nginx-loadbalancer.yml service/nginx created
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  • Check the created nginx service and we can see an IP address in the EXTERNAL-IP section 
$ kubectl get svc nginx NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE nginx LoadBalancer 10.96.43.161 172.18.255.200 80:30433/TCP 30s
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  • Access the application using external IP and port 
$ curl http://172.18.255.200:80 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> html { color-scheme: light dark; } body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html>
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Cleanup

  • Delete the cluster after use 
$ kind delete cluster --name dev Deleting cluster "dev" ... Deleted nodes: ["dev-worker2" "dev-control-plane" "dev-worker"]
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Reference

https://kind.sigs.k8s.io/



https://metallb.universe.tf/

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