Create a 3 Node Kubernetes Cluster with Minikube

This tutorial builds on my last tutorial Create a Kubernetes Cluster Using Docker Desktop. If you haven’t already, check it out first to learn how to create a proper Kubernetes Deployment YAML file. This tutorial will use minikube to create a three node cluster that includes one master and two worker nodes. We will then deploy ten Apache and four Redis services across the worker nodes.

Prerequisites:

• CLI
• Basic Kubernetes knowledge

Objectives:

• Install minikube on Mac CLI
• Create a 3 node cluster with one master node and two worker nodes
• Label 2 nodes as “worker”
• Deploy Redis with 4 replicas via Deployment YAML file
• Deploy Apache with 10 replicas via Deployment YAML file

I am installing minikube on a Mac and installation is different for Linux and Windows. You can find Linux and Windows installation instructions here.

Install Minikube on Mac CLI

To install minikube on x86–64 mac OS, run the following two commands:

curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-darwin-amd64
sudo install minikube-darwin-amd64 /usr/local/bin/minikube

Use the following command to start a cluster:

minikube start

Use the following command to confirm minikube is running:

minikube status

Create a 3 Node Cluster

We want to create a 3 node cluster that will consist of one master node (for the rest of the tutorial we will call this node “control-plane”) and two worker nodes. We can create a 3 node cluster by using the following command:

minikube start --nodes # -p <cluster_name>

The cluster may take several minutes to create, but minikube will output updates as things are happening. Once it says “Done!” use the following command to see the three nodes you just created.

kubectl get nodes

3 node cluster

Label Nodes

When we deploy our Redis and Apache pods, we do not want them to deploy to our control-plane, so we need to label our second and third nodes as “worker”. Use the following command to apply a worker label to the k8cluster-m02 and k8cluster-m03 nodes. You will have to run the command twice, once for each of the above nodes.

kubectl label node <node_name> node-role.kubernetes.io/worker=worker

Use the following command to view the newly labeled nodes.

kubectl get nodes

The YAML files that we will deploy will search for these worker nodes based on a key:value label pair. Use the following command to apply a key:value label to the worker nodes:

kubectl label nodes <node_name> role=worker

Run the command again for the second worker node (k8cluster-m03).

Redis Deployment YAML File

In my last tutorial Create a Kubernetes Cluster Using Docker Desktop, I went into detail on how to create a Kubernetes deployment YAML file, If you need to create a YAML file for the Redis and Apache deployments, please visit that tutorial now and come back when your files are created. Alternatively, you can just copy the code below for the Redis deployment with four replicas and save it an a .yml file.

apiVersion: apps/v1
kind: Deployment
metadata:
    name: redis-deploy
    labels:
        app: redis
spec: 
    replicas: 4
    selector:
        matchLabels:
            app: redis
    template: 
        metadata:
            labels:
                app: redis
        spec:
            containers:
            - name: redis
              image: redis:7.0.9
              ports:
              - containerPort: 6379 
            nodeSelector:
                role: worker

Notice in the file we’ve added nodeSelector on the container being created. With nodeSelector, we can choose which node our containers will be deployed on. Earlier we assigned our second and third nodes to be “worker” nodes and indicated that with the key:value pair role:worker. When we deploy this YAML file, the engine will look for any nodes that have the role:worker label and will deploy replicas on those nodes only. By using these labels, we are avoiding deploying replicas on the control-panel.

Apache Deployment YAML File

Here is the file contents for the Apache deployment with ten replicas.

apiVersion: apps/v1
kind: Deployment
metadata:
    name: httpd-deploy
    labels:
        app: httpd
spec:
    replicas: 10
    selector:
        matchLabels:
            app: httpd
    template:
        metadata:
            labels:
                app: httpd
        spec:
            containers:
            - name: httpd
              image: httpd:2.4.56
              ports:
              - containerPort: 80
            nodeSelector:
                role: worker

Note that these two files can actually be combined into one file by using --- to separate each manifest. To see what asingle file would look like, visit my GitHub here.

Deploy Redis and Apache Pods

Using the CLI, navigate to the directory that contains your Redis and Apache YAML files. Use the following command to deploy the pods:

kubectl apply -f <yaml_file.yml>

You will need to run this command twice. Once for the Redis YAML file and once for the Apache YAML file.

Your pods containing your replicas should have successfully deployed. To confirm this, use the following command:

kubectl get pods -o wide

You can see that all fourteen replicas are running and they are only running on the worker nodes (k8cluster-m02 and k8cluster-m03).

To get more information about what we just created, use the following command:

kubectl get all

With this command you can view all your replicas, your cluster IP that was automatically created, your two deployments, your replicaSets that were created from your YAML files, and your three nodes. You have now successfully created a Kubernetes cluster with one control-plane node and two worker nodes that are running fourteen pods.

Clean Up

Clean up is optional but is a good practice to save space on your local computer. To clean up what you just created, we need to delete the deployments and the nodes. You can delete both deployments in a single command:

kubectl delete deployments <httpd_deployment_name> <redis_deployment_name>

To delete your cluster nodes, use the following command:

kubectl delete nodes <node_name> <node_name> <node_name>

To stop minikube, run the following command:

minikube stop

To delete minikube, run the following command:

minikube delete

For more commands that you can run on your pods and clusters, check out this Kubernetes Cheat Sheet.

Thank you so much for following along with me on this DevOps journey and this new topic of Kubernetes. Until next time, keep moving forward!