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kind

kind is a tool for running local Kubernetes clusters using Docker container “nodes”. kind was primarily designed for testing Kubernetes itself, but may be used for local development or CI.

If you have go (1.11+) and docker installed GO111MODULE="on" go get sigs.k8s.io/kind@v0.10.0 && kind create cluster is all you need!

kind Installation

On Linux

$ curl -Lo ./kind https://kind.sigs.k8s.io/dl/v0.10.0/kind-linux-amd64
$ chmod +x ./kind
$ mv ./kind /some-dir-in-your-PATH/kind

On Mac

$ brew install kind

Usage

Creating Cluster

Run the kind command to create the cluster - 1 master node and 2 worker nodes

$ kind create cluster --config multi-nodes-config.yaml
# multi-nodes-config.yaml
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  # Configuration for Ingress
  kubeadmConfigPatches:
  - |
    kind: InitConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "ingress-ready=true"
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    protocol: TCP
  - containerPort: 443
    hostPort: 443
    protocol: TCP
- role: worker
- role: worker

Check the nodes

$ kubectl get nodes

NAME                 STATUS   ROLES                  AGE   VERSION
kind-control-plane   Ready    control-plane,master   23m   v1.20.2
kind-worker          Ready    <none>                 22m   v1.20.2
kind-worker2         Ready    <none>                 22m   v1.20.2

Ingress controller - Ingress NGINX

Installation

$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/kind/deploy.yaml

Waiting until is ready.

$ kubectl wait --namespace ingress-nginx \
  --for=condition=ready pod \
  --selector=app.kubernetes.io/component=controller \
  --timeout=90s

Load balancer - Metallb

If you set up Kind on the Mac, need to set up Virtual Network Interface. Because officially Mac OS is not allowed to connect the docker network. Please read my document.

Create metallb namespace

$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/master/manifests/namespace.yaml

Create the memberlist secrets

$ kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"

Apply metallb menifest

$ kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/master/manifests/metallb.yaml

Wait for metallb pods

$ kubectl get pods -n metallb-system --watch

Setup address pool used by loadbalancers

To complete layer2 configuration, we need to provide metallb a range of IP addresses it controls. We want this range to be on the docker kind network.

$ docker network inspect -f '{{.IPAM.Config}}' kind

The output will contain a cidr such as 172.19.0.0/16. We want our loadbalancer IP range to come from this subclass. We can configure metallb, for instance, to use 172.19.255.200 to 172.19.255.250 by creating the configmap.

apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
      - 172.19.255.200-172.19.255.250

Apply this contents

kubectl apply -f https://kind.sigs.k8s.io/examples/loadbalancer/metallb-configmap.yaml

Load balancer sample

kind: Service
apiVersion: v1
metadata:
  name: foo-service
spec:
  type: LoadBalancer
  selector:
    app: http-echo
  ports:
  # Default port used by the image
  - port: 5678

Persistant Volume Setting

I'm going to set up the application running up in the cluster which can have persistent volume whenever we restart our pod and cluster.

For that, we need to use the provisioner and this one can offer restoring volumes and full accessibility where our pod is turned up.

If you don't mind the full accessibility of the provisioner, you can use the local-path-provisioner made by Rancher labs. This is default local provisioner on Kind.

In this document, I will use the provisioner that can support full accessibility. (Refer this blog post)

We will change the Kind config file to use other provisioner like below. (kind-pvc-hostpath.yaml)

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: InitConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "ingress-ready=true"
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    protocol: TCP
  - containerPort: 443
    hostPort: 443
    protocol: TCP
  - containerPort: 30950
    hostPort: 30950
    protocol: TCP
  extraMounts:
  # This is the manifest for modified provisioner.
  - hostPath: ./kind-pvc-hostpath.yaml
    containerPath: /kind/manifests/default-storage.yaml
  - hostPath: /tmp/hostpath-provisioner
    containerPath: /tmp/hostpath-provisioner
- role: worker
  extraMounts:
  - hostPath: /tmp/hostpath-provisioner
    containerPath: /tmp/hostpath-provisioner
- role: worker
  extraMounts:
  - hostPath: /tmp/hostpath-provisioner
    containerPath: /tmp/hostpath-provisioner

Usage

In kind-pvc-hostpath.yaml, you can see the storage class basically created.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: default-storage-class
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
reclaimPolicy: Retain
provisioner: example.com/hostpath

So, you can just create Persistent Volumce Claim for your component using this storage class.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: jenkins-pvc
  labels:
    app: jenkins
spec:
  storageClassName: default-storage-class
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi