Build Jenkins Pipeline Using Git, Docker Hub, Podman and Kubernetes - Part 4

Now our Jenkins and Kubernetes configuration completed.

Let's start with pipeline deployment:

We need to understand Architecture first :

On your local machine , let's build python application:

from flask import Flask
 app = Flask(__name__)
 
 @app.route('/')
 def hello_world():
  return '<h1>Hello World from Flask!</h1>'
 
 if __name__ == "__main__":
  app.run(host="0.0.0.0", port=int("5000"), debug=True)

2. Dockerfile: A Dockerfile is a text document that contains all the commands a user needs to call on the command line to assemble an image. It is a set of instructions that Docker uses to build an image.

FROM python:3.9-slim-buster
 ADD hello.py /
 COPY . /app
 WORKDIR /app
 RUN pip3 install Flask
 EXPOSE 5000
 CMD [ "python3", "./hello.py" ]

3. For Kubernetes , we require Deployment yaml and Service Yaml .

deployment.yaml

apiVersion: apps/v1
 kind: Deployment
 metadata:
  creationTimestamp: null
  labels:
  app: hello
  name: hello
 spec:
  replicas: 5
  selector:
  matchLabels:
  app: hello
  strategy: {}
  template:
  metadata:
  creationTimestamp: null
  labels:
  app: hello
  spec:
  serviceAccountName: jenkins
  containers:
  - image: docker.io/vniks/jenkins-pipeline:v1
  name: python-hello-app
  ports:
  - name: hello
  containerPort: 5000
  protocol: TCP

Service.yaml

apiVersion: v1
 kind: Service
 metadata:
  creationTimestamp: null
  labels:
  app: hello
  name: hello-svc
 spec:
  ports:
  - port: 5000
  nodePort: 30080
  protocol: TCP
  targetPort: 5000
  selector:
  app: hello
  type: NodePort

Apart from this application files we need Podman container to Build and push image. So we need to create image with Podman installed.

FROM jenkins/inbound-agent:alpine
 USER root
 
 RUN apk add --no-cache --update podman fuse-overlayfs
 
 RUN sed -i 's/#mount_program/mount_program/' /etc/containers/storage.conf
 RUN echo jenkins:100000:65536 >/etc/subuid
 RUN echo jenkins:100000:65536 >/etc/subgid
 USER jenkins

Build this image and push in your dockerhub repository.

podman login docker.io
 podman build -t docker.io/vniks/python-hello-app:v1 .
 podman push vniks/python-hello-app:v1

For creating Pipeline we need Jenkinsfile with all required stages :

podTemplate(containers: [
  containerTemplate(name: 'podman', image: 'vniks/podman-agent:v1', command: 'cat', privileged: true, user: 'root', ttyEnabled: true),
  containerTemplate(name: 'kubectl', image: 'lachlanevenson/k8s-kubectl:latest', command: 'cat', ttyEnabled: true)
  ],
  volumes: [
  hostPathVolume(mountPath: '/run/podman/podman.sock', hostPath: '/run/podman/podman.sock')
 ]) {
 
  node(POD_LABEL) {
  stage('Get a git project') {
  git 'https://github.com/vnikhil89/jenkins-pipeline.git'
  container('podman') {
  stage('Build a docker image and push') {
  withCredentials([string(credentialsId: 'dockerhub-pwd', variable: 'dockerhubpwd')]){
  sh 'podman login docker.io -u vniks -p ${dockerhubpwd}'
  sh 'podman build -t docker.io/vniks/jenkins-pipeline:v1 .'
  sh 'podman push docker.io/vniks/jenkins-pipeline:v1'
  }
  }
  }
  stage('Deployment') {
  container('kubectl') {
  sh 'kubectl apply -f hello.yaml'
  sh 'kubectl apply -f hello-svc.yaml'
  }
  }
  }
  }
 }

In Pod template we need to specify which containers we want to start along with Jenkins-Inbound agent container. In my case i have used Podman container to build and push image to docker hub. Second container Kubectl which is required to create deployment and service on Kubernetes cluster.

We also require socket for communication between podman container and podman.

Let's Create Pipeline :

I have configured 15 min polling interval

Choose Option Pipeline script with SCM

You have to provide Git hub URL and credentials

Click Save

Let's click on Build Now

I am able to successfully deploy Hello pipeline.

Let's check deployment status :

Check service status

Tested my app , accessible on NodePort 30080.