Kubernetes : Running-Kubernetes-Locally-via-Minikube

Minikube starts a single node kubernetes cluster locally for purposes of development and testing.

Hello Minikube

Minikube packages and configures a Linux VM, Docker and all Kubernetes components, optimized for local development.

What Do We Need?

1. VirtualBox:
      Download the latest version (> 5.0) of VirtualBox.

2. Docker Toolbox:
      We will extensively use Docker Machine for the configuration. Download the stable version of Docker Toolbox.

3. Installing minikube:

# curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.18.0/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/

4. Install kubectl:
      kubectl is a requirement for using minikube. kubectl command-line tool, which you can use to interact with Kubernetes clusters.

# curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/v1.6.0/bin/linux/amd64/kubectl && chmod +x kubectl && sudo mv kubectl /usr/local/bin/

5. Starting the cluster:
We can run minikube command using either kvm or VirtualBox.
To start a cluster, run minikube with Virtualbox driver:

# minikube start --vm-driver="virtualbox"
Sarting local Kubernetes cluster...
Starting VM...
Downloading Minikube ISO
89.51 MB / 89.51 MB [==============================================] 100.00% 0s
SSH-ing files into VM...
Setting up certs...
Starting cluster components...
Connecting to cluster...
Setting up kubeconfig...
Kubectl is now configured to use the cluster.

Check the status of Minikube:

# minikube status

Check if kubectl is correctly configured:

# kubectl get componentstatuses
NAME                      STATUS      MESSAGE      ERROR
scheduler                Healthy        ok
controller-manager  Healthy       ok
etcd-0                      Healthy       {"health": "true"}

If Everything success, then we installed minikube successfully.
Now we deploy simple Hello-World Program using Docker

Hello-World Program

Deploy and Run in Kubernetes

Point the Docker CLI to minikube:

# eval $(minikube docker-env)

Later, when we no longer wish to use the Minikube host, we can undo this change by running:

# eval $(minikube docker-env -u)

Creating Node.js application

Find server.js code in hello-node/server.js

Creating a Docker container image

Dockerfile is available in hello-node/Dockerfile

# cd hello-node/
# docker build -f Dockerfile -t hello-node:v1 .
# docker images

Creating a Deployment

A Kubernetes Pod is a group of one or more Containers, tied together for the purposes of administration and networking. The Pod in this tutorial has only one Container. A Kubernetes Deployment checks on the health of our Pod and restarts the Pod's Container if it terminates.

Use the kubectl run command to create a Deployment that manages a Pod.
The Pod runs a Container based on our hello-node:v1 Docker image:

kubernetes-basics

# kubectl run hello-node --image=hello-node:v1 --port=8080
deployment "hello-node" created

To view the Deployment:
# kubectl get deployments

To view the Pod:
# kubectl get pods

To view cluster events:
# kubectl get events

Creating a Service

By default, the Pod is only accessible by its internal IP address within the Kubernetes cluster.
To make the hello-node Container accessible from outside the Kubernetes virtual network, we have to expose the Pod as a Kubernetes Service.

# kubectl expose deployment hello-node --type=LoadBalancer
service "hello-node" exposed

To view the Service we just created:
# kubectl get services

On Minikube, the LoadBalancer type makes the Service accessible through the minikube service command:

# minikube service hello-node
Opening kubernetes service default/hello-node in default browser...

OR you can create yaml conf file to deploy applications
Find conf files in hello-node directory

# kubectl create -f hello-node-pod.yml
pod "hello-node" created

#kubectl get pods

# kubectl create -f hello-node-svc.yml
service "hello-node" created

# kubectl get services

To go inside pod & run bosh command
# kubectl exec -it <pod_name> /bin/bash

Replication-Controller

Scale pods with replication-controller

# kubectl create -f hello-node-rc.yml
# kubectl get rc
To scale pods
# kubectl scale rc hello-node --replicas 5

Cleaning up

Now we can clean up the resources we created in our cluster:

# kubectl delete service hello-node
service "hello-node" deleted

# kubectl delete deployment hello-node
deployment "hello-node" deleted

To shut the cluster down, type "minikube stop":

# minikube stop
Stopping local Kubernetes cluster... Machine stopped.