CI/CD Pipeline Using Kubernetes

Task Description

1. Create container image that’s has Linux and other basic configuration required to run Slave for Jenkins. ( example here we require kubectl to be configured )

2. When we launch the job it should automatically starts job on slave based on the label provided for dynamic approach.

3. Create a job chain of job1 & job2 using build pipeline plugin in Jenkins 

Job1 : Pull the Github repo automatically when some developers push repo to Github and perform the following operations as:

• Create the new image dynamically for the application and copy the application code into that corresponding docker image
• Push that image to the docker hub (Public repository)  ( Github code contain the application code and Dockerfile to create a new image )

Job2 Launch the application on the top of Kubernetes cluster performing following operations:

• If launching first time then create a deployment of the pod using the image created in the previous job. Else if deployment already exists then do rollout of the existing pod making zero downtime for the user.
• If Application created first time, then Expose the application. Else don’t expose it.

Let's Start

As we have to control Docker using Jenkins, We will have to set-up Docker cloud on Jenkins. For this we will need Docker plugin.

Moreover We need to allow docker daemon to be accessed remotely. For this, we need to edit /usr/lib/systemd/system/docker.service.

ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:1234

#restart daemon and docker
systemctl daemon-reload
systemctl restart docker.service

Here 0.0.0.0:1234 denotes that any IP can be given to the host but the port must be 1234. Then, we will have to setup the Docker-cloud on Jenkins:

Manage Jenkins > Manage Nodes and Clouds > Configure Clouds > Add A New Cloud — Docker > Set the required parameters > Test connection

Job 1

• Pulling the Github repo automatically when some developers push repo to Github

For automation I used post-commit git hook. This hook ensures that the code gets pushed to Github as soon as the user commits, and also runs Job1 Using build triggers of Jenkins.

#!/bin/bash


git push
curl --user "admin:root" https://192.168.99.101:8080/job/Git%20Clone/build?token=job1

• Creating the new image dynamically for the application and copying the application code into that corresponding docker image and Push that image to the docker hub (Public repository)

I included the Dockerfile in the Git repo and used Docker plugin to build and push the Docker image automatically.

Console Output

Job2

• Launch the application on the top of Kubernetes cluster performing following operations:
• If launching first time then create a deployment of the pod using the image created in the previous job. Else if deployment already exists then do rollout of the existing pod making zero downtime for the user.
• If Application created first time, then Expose the application. Else don’t expose it.

I used yml file for deployment and used 3 replicas of pods for easy rollout.

apiVersion: apps/v1
	kind: Deployment
	metadata: 
	  name: web-deployment
	spec:
	  replicas: 3
	  selector:
	    matchLabels:
	      env: production
	  template:
	    metadata:
	      name: web-pod
	      labels:
	        env: production
	    spec:
	      containers: 
	      - name: httpd
	        image: 269mehta/webserver-httpd:latest

If Deployment is not present:

If Deployment is present (Rollout):

You can checkout the complete code at my Github Repo: