How To Configure Build Periodically In Jenkins?

Jenkin has now become a very popular open-source automation server used for building, testing, and deploying software. It has several key features, one of which is that it can schedule periodically in Jenkins. In this article, we are going to explore in depth how we can configure builds periodically in Jenkins.

Basic Terminologies of Build Scheduling

There are mainly four main terminologies, which are used in configuring a build periodically or in scheduling jobs in Jenkins.

• Build Trigger: Build trigger refers to the event that initiates a build
• Trigger Type: It defines how a build is triggered (for example, manually, periodically, because of SCM changes, or on any external events).
• Schedule Builder: It provides an interface for defining a build schedule (available via plugins).
• Cron Expression: A format for specifying recurring schedules using keywords or numbers (minutes, hours, days, months, weekdays).

Prerequisites for Configuring Build Periodically in Jenkins

These are the prerequisites that you should follow before configuring the build periodically in Jenkins. Here is the explanation:

• Jenkins Installation: Make sure you already have installed Jenkins and it is running on your server. If you don’t have Jenkins, you can simply install it by visiting their official website.
• Jenkins Project Setup: Create a Jenkins project if you haven’t already created one. You can do this by selecting “New Item” in the Jenkins dashboard and by choosing the appropriate project type like Freestyle project, Pipeline, etc.
• Access to the Jenkins Dashboard: Ensure you have access to the Jenkins web dashboard. You can typically access it through a web browser.

How to Configure Build periodically in Jenkins

Here is the step-by-step guide to configuring build periodically in Jenkins

Step 1: Log in to Jenkins Dashboard

This is the first step before proceeding further, You can log in to your Jenkin dashboard using your user ID and password.

Login to Jenkin

Step 2: Select a Project

Choose the Jenkins project for which you want to configure the periodic build. If you don’t have any project, you can create one by selecting “New Item” and then choosing the project type (e.g. Freestyle project, Pipeline).

Select the Project

Step 3: Configure Build Triggers

Within your project, first click on the configure tab then find the “Build Triggers” section. Check the “Build periodically” option.

Click on Configure

Navigate to Build Trigger

Step 4: Specify the Schedule

In the “Schedule” field, enter the cron expression that will defines when the build should run or in simple words which job will run when. The cron syntax have five fields representing these minute, hour, day of the month, month, and day of the week, respectively.For example: Jenkins provides a helpful “?” character that represent no specific value in the day of the week or day of the month fields.

To schedule build for every minute its cron expression look like this:

*****

Schedule Build for every minute

To schedule build for every 2 minute its cron expression look like this:

H/2****

Schedule Build for every 2 minute

Step 5: Save the Configuration

You can save the configuration by clicking on save button.

Click on Save

Step 6: Build Log Output

You can now observe the build log output at the scheduled intervals. Jenkins will initiate the build automatically based on the configured schedule.

Example of Cron Expressions

Schedule	Cron Expression	Description
Every minute	* * * * *	Run the job every minute.
Every hour	0 * * * *	Run the job at the beginning of every hour.
Every day at midnight	0 0 * * *	Run the job at midnight every day.
Every weekday at noon	0 12 * * 1-5	Run the job at 12:00 PM, Monday to Friday.
Every Sunday at 3:30 AM	30 3 * * 0	Run the job at 3:30 AM every Sunday.
Every 15 minutes	*/15 * * * *	Run the job every 15 minutes.
Every Monday and Friday	0 0 * * 1,5	Run the job at midnight, Monday and Friday.
First day of the month	0 0 1 * *	Run the job at midnight on the first day of the month.
Weekdays at 8 AM and 5 PM	0 8,17 * * 1-5	Run the job at 8 AM and 5 PM, Monday to Friday.

Remember:

These are the some point that you should remember while using corn expression to build periodically in Jenkins:

• You must understand your requirement first before choosing a scheduling method.
• Test your schedules thoroughly to assure that they run as per the expectation.
• You should timely monitor your builds to detect potential issues related to scheduling.

Conclusion

Configuring builds periodically in Jenkins is a powerful feature that make sure that the projects are automatically building at regular interval of time, it reduces manual intervention as most of the work is getting done automatically by machine itself eventually simplifies the process and faster it. By understanding and using cron expressions, You can build or schedule jobs periodically as per the project need easily.

How to Configure Build periodically in Jenkins- FAQ’s

What is a cron expression?

A cron expression is refer to the string that represents a schedule in the cron format. It mainly consists of five fields minute, hour, day of the month, month, and day of the week, in the same order. Special characters such as “*” and “?” represents specific values or wildcards during scheduling process.

How can I create a cron expression for particular schedule?

You can use online cron expression generators or manually write the expression using the minute, hour, day of the month, month, and day of the week fields. You must remember to test your cron expression to make sure that it behaves as expected.

How can I troubleshoot if my periodic build is not triggering?

You can check the Jenkins build logs for any error messages or issues. Ensure that the cron expression written by you is valid and correct. Additionally, verify that Jenkins has the all the necessary permissions requires to access your project and repository.

Can I configure multiple periodic build schedules for a single project?

Yes, you can specify multiple cron expressions in the build periodically field, each of them must be separated by newline characters. Each line will represent a different schedule for your project.