Docker image push from Jenkins to Dockerhub and deployment to Kubernetes cluster

Question

I am trying to implement CI/CD pipeline for my spring boot microservices. I am using Kubernetes and Jenkins for implementation of CI/CD pipeline. And also I am using SVN private code repository installed on on-premise server. And Kubernetes cluster forming using AWS EC2 Ubuntu 16.04 LTS AMI.

In my application I am planning to add Jenkinsfile and create shell script in VM for implementing the pipeline jobs. I am now exploring the following URLs for this:

1. https://www.brightbox.com/blog/2018/01/22/push-builds-to-dockerhub/
2. http://www.tothenew.com/blog/automated-docker-deployment-using-jenkins/
3. https://ropenscilabs.github.io/r-docker-tutorial/04-Dockerhub.html

Here I am seeing the script for pushing builded Docker image within Jenkinsfile. I understood the concept of Docker image pushing using configuration stage in Jenkinsfile. But here my doubt is that,

Confusion 1

If I am using Kubernetes cluster for deployment, can I directly add kubectl deployment command in Jenkinsfile ? Or Do I need to create any shell script in my VM?

Confusion 2

I have the Kubernetes cluster with 4 Vms - AWS EC2 Ubuntu 16.04 LTS. Ie, 1 Master and 3 worker machine.

So my another confusion is that, if I need to use one shell script in my Kubernetes cluster, in which Vm I need to write .sh file? Do I need to write in Master VM? Or need to add in worker Vm? Or need to add where I installed Jenkins master?

How the shell script can make to available in entire Kubernetes cluster?

Answer 1

Yes, you can use shell scripts to call kubectl, from your Jenkinsfile, for example:

sh 'kubectl ...'

However, my advice would be to use a shell script and put your commands inside that.

For an example, see: https://wade.be/development/2018/04/30/jenkinsfiles.html

Your shell script doesn't need to be in a VM at all, it just needs to be accessible by the Jenkins server.

Put it inside the code repository alongside where you store your Jenkinsfile.