Multibranch pipeline in Jenkins

Devops Tutorial​​ 27 -​​ Multibranch pipeline​​ in Jenkins

In​​ real scenario, multiple developers would be working on their respective branches. For example, developer1 would be working on feature1 and developer2 would be working on feature2 and so on. All the developers might want to execute their Jenkinsfile on their respective branches. So here comes the need of Multibranch pipeline in Jenkins.

To start, just go to github repository that we created earlier and copy the HTTPS link of project as shown below​​ 

Note: The Jenkinsfile that you see above is part of main branch

Next, open git bash shell and execute the following steps to clone the Github repository to your local machine. The syntax is:​​ git clone <project name that you copied above>

So we now have the remote project on our local machine. Let us cd to this project​​ as shown below. We can now see that we are in ‘main’ branch and when we do ‘ls’, we see the Jenkinsfile as part of this main branch

We can see the contents of this file as shown below​​ 

‘git status’ command o/p is self-explanatory​​ 

‘git branch’ command o/p shows that we right now have only 1 branch viz main

Create a new branch feature_1

‘git branch’ command o/p now shows 2 branches and we are right now on branch main (shown by asterisk *)

Checkout the feature_1 branch in local machine

‘git branch’ command o/p now shows we are on branch feature_1 (shown by asterisk *).​​ 

Also notice below that we now see (feature_1) instead of (main)

Let us checkout Jenkinsfile from main branch into feature_1 branch

Edit the Jenkinsfile

Add an additional line

Save​​ and close the file.

To double check, see the file contents, you should see the new line that you have added​​ 

Below command are self-explanatory

Push the Jenkinsfile to feature_1 branch​​ 

Copy above command and execute

You might be asked to enter Git credentials

You might get below error

To resolve this, generate token by following​​ steps mentioned in​​ below link

https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token​​ 

Execute the push command one more

Enter username and password (will be your token)

Click Ok

You might be to enter username and password again​​ 

Click Ok

Notice below that push is now successful

Refresh github.​​ 

You now see​​ 2 branches, see below

Switch to feature_1 branch​​ by clicking feature_1.

You can see Jenkinsfile in this branch as shown below

Click this file, you can see the new line that we had added

So we now have Jenkinsfile in 2 branches: main and feature_1

We​​ will execute the Jenkinsfile on both of these branches in Jenkins.

To do that, create a Multibranch pipeline job in jenkins

Under 'Branch sources', select 'Git' from​​ ‘Add source’​​ dropdown​​ 

Copy project link

In jenkins, paste it in​​ project repository

Let the script path be Jenkinsfile, see below

Retain other default values.

Apply and save.

After sometime you would see​​ 2 pipelines running​​ (for the 2 branches)

Click​​ ‘Scan Multibranch Pipeline Log’ that you see on left hand side

Notice in the logs below that Jenkinsfile is found and executed successfully on both the branches​​ 

Thank you for reading!