Auto Rolling-update in K8s using Dynamic Jenkins Cluster.

Preface

Jenkins is an open-source automation tool written in Java with plugins built for Continuous Integration purposes. Jenkins is used to build and test your software projects continuously making it easier for developers to integrate changes to the project, and making it easier for users to obtain a fresh build. It also allows you to continuously deliver your software by integrating with a large number of testing and deployment technologies.

With Jenkins, organizations can accelerate the software development process through automation. Jenkins integrates development life-cycle processes of all kinds, including build, document, test, package, stage, deploy, static analysis, and much more.

A Slave is a Java executable that runs on a remote machine. Following are the characteristics of Jenkins Slaves:

  • It hears requests from the Jenkins Master instance.
  • Slaves can run on a variety of operating systems.
  • The job of a Slave is to do as they are told to, which involves executing build jobs dispatched by the Master.
  • You can configure a project to always run on a particular Slave machine or a particular type of Slave machine, or simply let Jenkins pick the next available Slave.

Create A dynamic Jenkins cluster and perform task-3 using the dynamic Jenkins cluster.

  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
    4. Job1 : Pull the Github repo automatically when some developers push repo to Github and perform the following operations as:
    1. Create the new image dynamically for the application and copy the application code into that corresponding docker image
    2. Push that image to the docker hub (Public repository)
    ( Github code contain the application code and Dockerfile to create a new image )
    5. Job2 ( Should be run on the dynamic slave of Jenkins configured with Kubernetes kubectl command): Launch the application on the top of Kubernetes cluster performing following operations:
    1. 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.
    2. If Application created first time, then Expose the application. Else don’t expose it.

First we have to configure the Windows slave node.

FROM centos:latest

RUN yum install net-tools httpd php -y

COPY * /var/www/html/

EXPOSE 80/tcp

CMD [“/usr/sbin/httpd”, “-DFOREGROUND”]

Thank you for reading…..

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