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Unni P
Unni P

Posted on • Originally published at iamunnip.hashnode.dev

kind - Setting up Load Balancer using MetalLB - Part 6

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 donโ€™t run on a cloud provider

  • Sets up MetalLB using layer2 protocol

  • We can send traffic directly to the load balancerโ€™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" ...
 โœ“ Ensuring node image (kindest/node:v1.26.3) ๐Ÿ–ผ
 โœ“ Preparing nodes ๐Ÿ“ฆ ๐Ÿ“ฆ ๐Ÿ“ฆ  
 โœ“ Writing configuration ๐Ÿ“œ 
 โœ“ Starting control-plane ๐Ÿ•น๏ธ 
 โœ“ Installing CNI ๐Ÿ”Œ 
 โœ“ Installing StorageClass ๐Ÿ’พ 
 โœ“ Joining worker nodes ๐Ÿšœ 
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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