Create a cluster with Kubernetes-Create a cluster with Minikube

1. Use Minikube to create a cluster

1. Kubernetes cluster

Kubernetes coordinates a cluster of highly available computers, each connected to work as an independent unit. Abstractions in Kubernetes allow you to deploy containerized applications to a cluster without tying them to a particular stand-alone computer. In order to use this new deployment model, applications need to be packaged in a way that separates the application from a single host: they need to be containerized. Compared with the past deployment model in which applications are directly integrated with hosts in the form of packages, containerized applications are more flexible and available. Kubernetes automates the distribution and scheduling of application containers across clusters in a more efficient manner. Kubernetes is an open source platform and can be used in production environments.

A Kubernetes cluster contains two types of resources:

Control Plane schedules the entire cluster
Nodes are responsible for running applications

2. Cluster diagram

Control Plane is responsible for managing the entire cluster. The Control Plane coordinates all activities in the cluster, such as scheduling applications, maintaining the desired state of applications, scaling applications, and rolling out new updates.
A Node is a virtual machine or a physical machine that acts as a working machine in a Kubernetes cluster. Each Node has a Kubelet, which manages the Node and acts as an agent for the communication between the Node and the Control Plane. Node should also have tools for handling container operations, such as Docker or rkt. A Kubernetes cluster handling production-grade traffic should have at least three Nodes, because if a Node fails its corresponding etcd members and control plane instances are lost and redundancy suffers. You can reduce this risk by adding more control plane nodes.
Control Plane manages the cluster, and Node hosts running applications.
When deploying an application on Kubernetes, you tell the Control Plane to start the application containers. Control Plane arranges containers to run on the Nodes of the cluster. Node communicates with Control Plane using the Kubernetes API exposed by Control Plane. End users can also interact with the cluster using the Kubernetes API.
Kubernetes can be deployed on both physical machines and virtual machines. You can start deploying a Kubernetes cluster using Minikube. Minikube is a lightweight Kubernetes implementation that creates VMs on your local machine and deploys simple clusters consisting of just one node. Minikube is available for Linux, macOS and Windows systems. The Minikube CLI provides various operations for bootstrapping cluster jobs, including start, stop, view status, and delete.

3. Create a Minikube cluster

First make sure that minikube and kubectl have been installed.

minikube start

4. Open the dashboard

Open the Kubernetes dashboard. You can do this in two different ways:

Open a new terminal and run:

# Start a new terminal and keep this command running.
minikube dashboard

Now, switch back to the terminal where you ran minikube start .

If you don’t want Minikube to open a web browser for you, you can run dashboard commands with the --url flag. minikube will output a URL which you can open in your favorite browser.

Open a new terminal and run:

# Start a new terminal and keep this command running.
minikube dashboard --url

Now, switch back to the terminal where you ran minikube start .

5. Create a Deployment

A Kubernetes Pod is a group of one or more containers bound together for management and networking purposes. The Pod in this tutorial has only one container. Kubernetes Deployment checks the health of the Pod and restarts new containers in the event that a container in the Pod terminates. Deployments are the recommended way to manage Pod creation and scaling.

Use the kubectl create command to create a Deployment that manages Pods. The Pod runs containers based on the provided Docker image.

# Run a test container image containing a web server
kubectl create deployment hello-node --image=registry.k8s.io/e2e-test-images/agnhost:2.39 -- /agnhost netexec --http-port=8080

View Deployments:

kubectl get deployments

The output is similar to this:

NAME READY UP-TO-DATE AVAILABLE AGE
hello-node 1/1 1 1 1m

View pods:

kubectl get pods

The output is similar to this:

NAME READY STATUS RESTARTS AGE
hello-node-5f76cf6ccf-br9b5 1/1 Running 0 1m

View cluster events:
```
kubectl get events
```

View kubectl configuration:
```
kubectl config view
```

6. Create Service

By default, Pods are only accessible via internal IP addresses within the Kubernetes cluster. To make the hello-node container accessible from outside the Kubernetes virtual network, you must expose the Pod as a Kubernetes Service.

Use the kubectl expose command to expose the Pod to the public network:
```
kubectl expose deployment hello-node --type=LoadBalancer --port=8080
```
The --type=LoadBalancer parameter here indicates that you want to expose your Service to the outside of the cluster.

The application code in the test image only listens on TCP port 8080. If you expose other ports with kubectl expose , clients will not be able to access other ports.

Check out the Service you created:
```
kubectl get services
```
The output is similar to this:
```
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
hello-node LoadBalancer 10.108.144.78 <pending> 8080:30369/TCP 21s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 23m
```
For cloud service platforms that support load balancers, the platform will provide an external IP to access the service. On Minikube, LoadBalancer makes services accessible with the command minikube service.

Run the command below:
```
minikube service hello-node
```
This will open a browser window that will serve your application and display the application’s response.

7. Enable addons

Minikube has a set of built-in plugins that can be enabled, disabled, and turned on in the local Kubernetes environment.

List currently supported plugins:

minikube addons list

The output is similar to this:

addon-manager: enabled
dashboard: enabled
default-storageclass: enabled
efk: disabled
freshpod: disabled
gvisor: disabled
helm-tiller: disabled
ingress: disabled
ingress-dns: disabled
logviewer: disabled
metrics-server: disabled
nvidia-driver-installer: disabled
nvidia-gpu-device-plugin: disabled
registry: disabled
registry-creds: disabled
storage-provisioner: enabled
storage-provisioner-gluster: disabled

Enable plugins such as metrics-server:

minikube addons enable metrics-server

The output is similar to this:

The 'metrics-server' addon is enabled

View the Pods and Services created by installing the plugin:

kubectl get pod,svc -n kube-system

The output is similar to this:

NAME READY STATUS RESTARTS AGE
pod/coredns-5644d7b6d9-mh9ll 1/1 Running 0 34m
pod/coredns-5644d7b6d9-pqd2t 1/1 Running 0 34m
pod/metrics-server-67fb648c5 1/1 Running 0 26s
pod/etcd-minikube 1/1 Running 0 34m
pod/influxdb-grafana-b29w8 2/2 Running 0 26s
pod/kube-addon-manager-minikube 1/1 Running 0 34m
pod/kube-apiserver-minikube 1/1 Running 0 34m
pod/kube-controller-manager-minikube 1/1 Running 0 34m
pod/kube-proxy-rnlps 1/1 Running 0 34m
pod/kube-scheduler-minikube 1/1 Running 0 34m
pod/storage-provisioner 1/1 Running 0 34m

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/metrics-server ClusterIP 10.96.241.45 <none> 80/TCP 26s
service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 34m
service/monitoring-grafana NodePort 10.99.24.54 <none> 80:30002/TCP 26s
service/monitoring-influxdb ClusterIP 10.111.169.94 <none> 8083/TCP,8086/TCP 26s

Disable metrics-server:

minikube addons disable metrics-server

The output is similar to this:

metrics-server was successfully disabled

8. Clean up

Now it’s time to clean up the resources you created in the cluster:

kubectl delete service hello-node
kubectl delete deployment hello-node

Stop the Minikube cluster:

minikube stop

Optionally, delete the Minikube virtual machine (VM):

# optional
minikube delete

If you still want to use Minikube to further learn Kubernetes, there is no need to remove Minikube.

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