Jenkins WAR file execution - Step-by-Step Execution

Process Flow - Jenkins WAR file execution

Download jenkins.war

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Open terminal/command prompt

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Run: java -jar jenkins.war

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Jenkins server starts

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Access Jenkins via browser at localhost:8080

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Unlock Jenkins with initial admin password

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Configure Jenkins and start using

This flow shows how to start Jenkins by running the WAR file with Java, then access and unlock Jenkins in the browser.

Execution Sample

Jenkins

java -jar jenkins.war

Starts the Jenkins server by running the WAR file with Java.

Process Table

Step	Action	Command/Output	System State
1	Download Jenkins WAR file	jenkins.war downloaded	WAR file ready on disk
2	Open terminal	Terminal ready	Ready to run commands
3	Run Jenkins WAR	java -jar jenkins.war	Jenkins server starting...
4	Jenkins server startup logs	Loading plugins... Jenkins is fully up and running	Jenkins server running on port 8080
5	Open browser	Navigate to http://localhost:8080	Browser connected to Jenkins server
6	Unlock Jenkins	Enter initial admin password from file	Jenkins unlocked, ready for setup
7	Configure Jenkins	Setup wizard runs	Jenkins configured and ready to use

💡 Jenkins server is running and accessible via browser after setup

Status Tracker

Variable	Start	After Step 3	After Step 4	After Step 6	Final
jenkins.war	Not downloaded	Downloaded	Downloaded	Downloaded	Downloaded
Jenkins Server	Stopped	Starting	Running	Running	Running
Browser Access	No	No	No	Yes (locked)	Yes (unlocked)
Admin Password	Not retrieved	Not retrieved	Not retrieved	Retrieved and entered	Entered

Key Moments - 3 Insights

Why do we use 'java -jar jenkins.war' to start Jenkins?

Because Jenkins is packaged as a WAR file that runs on a Java server, so the command tells Java to run that WAR file as a web application. See execution_table step 3.

What does 'Unlock Jenkins' mean and why is it needed?

Unlocking Jenkins means entering the initial admin password to secure the server before setup. This happens after Jenkins starts (step 6) to prevent unauthorized access.

Why do we access Jenkins at http://localhost:8080 after starting the WAR file?

Because Jenkins runs a web server on port 8080 by default, so the browser connects to that address to interact with Jenkins. See execution_table step 5.

Visual Quiz - 3 Questions

Look at the execution table, what is the system state after step 4?

A Jenkins WAR file is still downloading

B Jenkins server is running on port 8080

C Browser has connected to Jenkins

D Jenkins is locked and not running

💡 Hint

Check the 'System State' column for step 4 in the execution_table

At which step do we enter the initial admin password to unlock Jenkins?

A Step 6

B Step 5

C Step 3

D Step 7

💡 Hint

Look for 'Unlock Jenkins' action in the execution_table

If we change the port Jenkins runs on, which step's system state would change?

A Step 1

B Step 6

C Step 4

D Step 7

💡 Hint

The port is part of the Jenkins server running state shown in step 4

Concept Snapshot

Jenkins WAR file execution:
- Download jenkins.war file
- Run with: java -jar jenkins.war
- Jenkins starts on port 8080
- Access via browser at http://localhost:8080
- Unlock with initial admin password
- Configure Jenkins and start using

Full Transcript

To run Jenkins from the WAR file, first download the jenkins.war file. Then open your terminal or command prompt. Run the command 'java -jar jenkins.war' to start the Jenkins server. The server will start and listen on port 8080 by default. Open your web browser and go to http://localhost:8080. Jenkins will ask you to unlock it by entering the initial admin password found in a file on your system. After unlocking, you can configure Jenkins using the setup wizard and start using it.