Deploying web-server using Jenkins-Groovy-code and Kubernetes

Skabhi

6 min readJul 12, 2020

Task Overview:

1. Create container image that’s has Jenkins installed using dockerfile.

2. When we launch this image, it should automatically start Jenkins service in the container.

3. Create a job chain of job1, job2, job3 and job4 using build pipeline plugin in Jenkins

4. Seed Job: Pull the Github repo automatically when some developers push the repo to Github.

5. Further on jobs should be pipeline using written code using Groovy language by the developer

6. Job1 :

1. By looking at the code or program file, Jenkins should automatically start the respective language interpreter installed image container 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 using PVC ( If server collects some data like logs, other user information )

7. Job2: Test your app if it is working or not.

8. Job3: if app is not working, then send email to the developer with error messages and redeploy the application after code is being edited by the developer.

About the DSL :

The DSL is scriptable via Groovy and so it is extremely flexible. The DSL also provides direct control over a job’s XML; this makes it possible to automate the creation of any job, regardless of what has been implemented in the DSL. A lot of helper methods are provided which makes it very easy to set up things such as build triggers, version control, shell scripts, and more.

Step 1 : Creating Dockerfile For Jenkins.

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
COPY .kube /root/.kube


RUN mkdir -p /home/jenkins


EXPOSE 8080


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

To build this image use the command as shown below :

docker build -t skabhi003/jenkins:v1 .

After build is complete push it do docker hub so that anyone can use it .

docker push skabhi003/jenkins:v1

Step 2 : Use the above created image to run the jenkins on top of Kubernetes using the YAML file.

apiVersion: v1
kind: Service
metadata:
  name: jenkins
  labels:
    app: jenkins
spec:
  ports:
    - port: 8080
  selector:
    app: jenkins
  type: ClusterIP
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: jenkins-claim
  labels:
    app: jenkins
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
---
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: skabhi003/jenkins:v10
        name: jenkins
        ports:
        - containerPort: 8080
          name: jenkins
        volumeMounts:
        - name: jenkins-storage
          mountPath: /root/.jenkins/
      volumes:
      - name: jenkins-storage
        persistentVolumeClaim:
          claimName: jenkins-claim