CI/CD Pipeline Automation Using Kubernetes

Kubernetes (commonly stylized as k8s) is an open-source container orchestration system for automating application deployment, scaling, and management. It aims to provide a “platform for automating deployment, scaling, and operations of application containers across clusters of hosts”. It works with a range of container tools, including Docker. In other words, you can cluster together groups of hosts running Linux containers, and Kubernetes helps you easily and efficiently manage those clusters.

It helps you fully implement and rely on a container-based infrastructure in production environments. And because Kubernetes is all about automation of operational tasks, you can do many of the same things other application platforms or management systems let you do — but for your containers.

In order to meet changing business needs, your development team needs to be able to rapidly build new applications and services. Cloud-native development starts with microservices in containers, which enables faster development and makes it easier to transform and optimize existing applications.

In this article, I’m going to perform the following tasks…

1. Create container image that’s has Jenkins installed using dockerfile or can use the Jenkins Server on RHEL 8/7.
2. When we launch this image, it should automatically starts Jenkins service in the container.
3. Create a job chain of job1, job2, job3 and job4 using build pipeline plugin in Jenkins.
4. Job1 : Pull the Github repo automatically when some developers push repo to Github.
5. Job2 :
   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 ( If server collects some data like logs, other user information )
6. Job3 : Test your app if it is working or not.
7. Job4 : if app is not working , then send email to developer with error. messages and redeploy the application after code is being edited by the developer.

Step 1: Start minikube and get its IP.

• minikube start
• minikube ip

Step 2: Copy these three files from windows to rhel8 for configuration.

C:\Users\ROHAN\.minikube\ca.crtC:\Users\ROHAN\.minikube\profiles\minikube\client.crtC:\Users\ROHAN\.minikube\profiles\minikube\client.key

Step 3: Create a Jenkins image with kubectl installed on it. Configuration files will be given to it by mounting a directory.

Dockerfile:

Now use the build command:

docker build -t jenkin:kubectl .

Step 4: Now start the container, login and set up the Jenkins.

docker run -it -v ~/kube-files:/root/.kube -P jenkin:kubectl

The contents of the config file :

apiVersion: v1
clusters:
- cluster:
    certificate-authority: ca.crt
    server: https://192.168.99.100:8443
name: minikube
contexts:
- context:
    cluster: minikube
    user: minikube
  name: minikube
current-context: minikube
kind: Config
preferences: {}
users:
- name: minikube
  user:
    client-certificate: client.crt
    client-key: client.key

Now our kubectl is completely configured on the rhel8 workstation.

Step 6: Job2 execute shell commands.

Step 7: Integrate Job3 with the following code to copy the files from GitHub to our pods.

#!/usr/bin/python3
  
import oscmd = os.popen("kubectl get pods | grep webserver")
cmd_op = cmd.read()
x = cmd_op.split('\n')
del x[-1]
for y in x:
    z = y.split()
    print(z)
    os.system("kubectl cp /root/.jenkins/workspace/job1/* {}:/usr/local/apache2/htdocs/".format(z[0]))

Step 8: Job4 will notify you using email if this build fails.

Now, we don’t require a monitoring job as this will be handled by k8s.

Now test it by connecting to minikube,

C:\Users\ROHAN\.minikube\profiles\minikube> kubectl get all
NAME                             READY   STATUS    RESTARTS   AGE
pod/webserver-85b3b5597d-78rwl   1/1     Running   0          4h
pod/webserver-85b3b5597d-kvnzc   1/1     Running   0          4h
pod/webserver-85b3b5597d-pwkzc   1/1     Running   0          4hNAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        4h
service/webserver    NodePort    10.96.68.216   <none>        80:32040/TCP   5hNAME                        READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/webserver   3/3     3            3           4hNAME                                   DESIRED   CURRENT   READY   AGE
replicaset.apps/webserver-85b3b5597d   3         3         3       4h

Now testing the webserver,

C:\Users\ROHAN>curl 192.168.99.100:32040Welcome!!!!

THANK YOU!!

My Linkedin - Rohan Khandelwal