Deploying web-server using Jenkins and Kubernetes

Task Overview:

• Create a container image that’s has Jenkins installed using Dockerfile.
• When we launch this image, it should automatically start the Jenkins service in the container.
• Create a job chain of job1, job2, job3 and job4 using build pipeline plugin in Jenkins
• Job1: Pull the Github repo automatically when some developers push the repo to Github.
• Job2 :

1. By looking at the code or program file, Jenkins should automatically start the respective language interpreter installed image pod to deploy code on top of Kubernetes ( eg. If code is of PHP, then Jenkins should start the container that has PHP already installed )

2. Expose your pod so that testing team could perform the testing on the pod

3. Make the data to remain persistent ( If server collects some data like logs, other user information )

• Job3: Test your app if it is working or not.

Project Description:

1. Create Jenkins installed Dockerfile:

FROM centos:latest

RUN yum install wget -y

RUN wget -O /etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-stable/jenkins.repo

RUN rpm — import https://pkg.jenkins.io/redhat-stable/jenkins.io.key

RUN yum install java-11-openjdk.x86_64 -y

RUN yum install jenkins -y

RUN yum install git -y

RUN yum install python3 net-tools -y

RUN echo -e “jenkins ALL=(ALL) NOPASSWD: ALL” >> /etc/sudoers

RUN curl -LO https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl

RUN chmod +x ./kubectl

RUN mv ./kubectl /usr/local/bin/kubectl

EXPOSE 8080

CMD [ “java”, “-jar”, “/usr/lib/jenkins/jenkins.war” ]

Save this file with name Dockerfile and build the image with command “docker bulid -t <image name>. “

This image push it to in docker hub because it is used in the kubernetes

• Running Jenkins server on top of Kubernetes with persistent storage.

For this ,the best way is to create a yaml file

apiVersion: v1
kind: Service
metadata:
  name: jenkins
  labels:
    app: jenkins
spec:
  ports:
    - port: 8080
  selector:
    app: jenkins
  type: NodePort
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: jenkins-claim
  labels:
    app: jenkins
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: jenkins
  labels:
    app: jenkins
spec:
  selector:
    matchLabels:
      app: jenkins
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: jenkins
    spec:
      containers:
      - image: guptakanav1999/kanav_jenkin
        name: jenkins
        ports:
        - containerPort: 8080
          name: jenkins
        volumeMounts:
        - name: jenkins-storage
          mountPath: /root/.jenkins/
      volumes:
      - name: jenkins-storage
        persistentVolumeClaim:
          claimName: jenkins-claim

First we have to run kubernetes by using this command “minikube start”

Now we have to run yaml file using command “kubectl apply -f <file name>”

For running jenkin we need ip address

For the password, Run “kubectl logs pod_name”

2. Jobs in Jenkins:

• Job1(Copy Github Code):

Whenever the developer pushes any code in Github, this job automatically detects and copy in host OS.

• Job2(Deploy deployment for website):

If my job1 is successfully built, it triggers job2 and launches the container.

if kubectl get pods | grep httpd
then
echo “service is running”
else
kubectl create -f /code/http.yaml
sleep 20
POD=$(kubectl get pod -l app=httpd -o jsonpath =”{.items[0].metdata.name}”)
kubectl cp /code/*.html $POD:/var/www/html
fi

html.yaml is below

apiVersion: v1
kind: Service
metadata:
  name: httpd
  labels:
    app: httpd
spec:
  ports:
    - nodePort: 80
      port: 80
      protocol: TCP
      targetPort: 80
  selector:
    app: httpd
  type: NodePort
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: httpd-claim
  labels:
    app: httpd
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: httpd
  labels:
    app: httpd
spec:
  selector:
    matchLabels:
      app: httpd
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: httpd
    spec:
      containers:
      - image: gaurav0417/http-server
        name: httpd
        ports:
        - containerPort: 8080
          name: httpd
        volumeMounts:
        - name: httpd-storage
          mountPath: /var/www/html/
      volumes:
      - name: httpd-storage
        persistentVolumeClaim:
          claimName: httpd-claim

• Job3(Testing that website is running or not)

After successfully build, Job2 will trigger Job3 and it checks the website that is working or not.