Creating first admin user in Jenkins - Try It Yourself

Creating first admin user

📖 Scenario: You have just installed Jenkins, a popular automation server. To start using Jenkins securely, you need to create the first admin user. This user will have full control over Jenkins and can manage other users and settings.

🎯 Goal: Learn how to create the first admin user in Jenkins by editing the configuration file and verifying the user creation.

📋 What You'll Learn

Create the initial Jenkins security configuration file with no users

Add a configuration entry for the first admin user with username and password

Apply the configuration to Jenkins by restarting or reloading

Verify the admin user creation by checking the Jenkins users directory

💡 Why This Matters

🌍 Real World

Creating the first admin user is a critical step after installing Jenkins to secure the server and manage access.

💼 Career

Understanding Jenkins user management is essential for DevOps engineers and system administrators to maintain secure CI/CD pipelines.

1

Create initial Jenkins security configuration file

Create a file named config.xml with the root element hudson.security.HudsonPrivateSecurityRealm_-Details and no users inside it.

Jenkins

  


# Your code here

Hint

This XML file defines Jenkins security realm details. Start with an empty root element.

2

Add first admin user configuration

Inside the config.xml, add a user element with id set to admin and a passwordHash element with the value {SHA}5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8 (which is the SHA-1 hash for password 'password').

Jenkins

  
  # Your code here

Hint

The passwordHash uses SHA-1 hash format. Use the exact hash string given.

3

Apply configuration by restarting Jenkins

Write the shell command sudo systemctl restart jenkins to restart Jenkins and apply the new user configuration.

Jenkins

  
    admin
    {SHA}5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8
  


# Write the command to restart Jenkins below
# Your code here

Hint

Use systemctl restart jenkins with sudo to restart the Jenkins service.

4

Verify admin user creation

Write the shell command ls /var/lib/jenkins/users/admin to check if the admin user directory exists.

Jenkins

  
    admin
    {SHA}5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8
  

sudo systemctl restart jenkins

# Write the command to verify admin user directory below
# Your code here

Hint

If the directory exists, the command will list the 'admin' folder, confirming the user creation.

Practice

1. Why is it important to create the first admin user in Jenkins?

easy

A. To speed up the build process

B. To secure the Jenkins server by controlling access

C. To reduce the server's memory usage

D. To automatically install plugins

Solution

1. Step 1: Understand Jenkins security basics

   Jenkins requires an admin user to control who can access and manage the server.

2. Step 2: Recognize the role of the first admin user

   This user sets permissions and protects the server from unauthorized access.

3. Final Answer:

   To secure the Jenkins server by controlling access -> Option B

4. Quick Check:

   Security = Control access [OK]

Hint: First admin user controls access and security [OK]

Common Mistakes:

• Thinking admin user speeds up builds
• Confusing admin user with plugin installer
• Believing admin user reduces memory use

2. Which of the following is the correct syntax to create a new admin user using Jenkins Groovy script console?

easy

A. jenkins.createUser('admin', 'password')

B. Jenkins.instance.createUser('admin', 'password')

C. Jenkins.security.createAccount('admin', 'password')

D. jenkins.model.Jenkins.instance.securityRealm.createAccount('admin', 'password')

Solution

1. Step 1: Recall Jenkins Groovy script for user creation

   The correct method to create a user is via the securityRealm's createAccount method.

2. Step 2: Match the exact syntax

   jenkins.model.Jenkins.instance.securityRealm.createAccount('admin', 'password') is the valid syntax.

3. Final Answer:

   jenkins.model.Jenkins.instance.securityRealm.createAccount('admin', 'password') -> Option D

4. Quick Check:

   securityRealm.createAccount = correct syntax [OK]

Hint: Use securityRealm.createAccount to add users [OK]

Common Mistakes:

• Using Jenkins.instance.createUser which does not exist
• Calling jenkins.createUser directly
• Using Jenkins.security.createAccount which is invalid

3. What will be the result of running this Groovy script in Jenkins script console?

def instance = jenkins.model.Jenkins.instance
instance.securityRealm.createAccount('admin', 'admin123')

medium

A. Creates a new admin user named 'admin' with password 'admin123'

B. Throws an error because createAccount is undefined

C. Deletes the existing admin user

D. Changes the Jenkins system password

Solution

1. Step 1: Analyze the script commands

   The script gets the Jenkins instance and calls createAccount on securityRealm with username and password.

2. Step 2: Understand createAccount effect

   This method creates a new user with the given credentials in Jenkins.

3. Final Answer:

   Creates a new admin user named 'admin' with password 'admin123' -> Option A

4. Quick Check:

   createAccount adds user = Creates a new admin user named 'admin' with password 'admin123' [OK]

Hint: createAccount adds user with given name and password [OK]

Common Mistakes:

• Assuming it deletes users
• Expecting a system password change
• Thinking createAccount is undefined

4. You tried to create the first admin user with this script:

jenkins.model.Jenkins.instance.securityRealm.createAccount('admin')

Why does it fail?

medium

A. Missing password argument in createAccount method

B. Incorrect method name, should be createUser

C. Jenkins instance is not accessible in script console

D. Username 'admin' is reserved and cannot be used

Solution

1. Step 1: Check method parameters

   createAccount requires two parameters: username and password.

2. Step 2: Identify missing argument

   The script only provides username, missing the password argument, causing failure.

3. Final Answer:

   Missing password argument in createAccount method -> Option A

4. Quick Check:

   Two arguments needed = Missing password argument in createAccount method [OK]

Hint: createAccount needs username and password [OK]

Common Mistakes:

• Using wrong method name
• Assuming Jenkins instance is inaccessible
• Thinking 'admin' username is reserved

5. You want to automate creating the first admin user during Jenkins startup using an initialization Groovy script. Which approach is correct?

hard

A. Add the user credentials in config.xml directly

B. Run the createAccount command manually after Jenkins starts

C. Place a Groovy script with createAccount call in init.groovy.d directory

D. Modify Jenkins WAR file to include the user

Solution

1. Step 1: Understand Jenkins initialization scripts

   Jenkins runs Groovy scripts placed in init.groovy.d folder during startup.

2. Step 2: Automate user creation

   Placing a script with createAccount call there creates the admin user automatically on startup.

3. Final Answer:

   Place a Groovy script with createAccount call in init.groovy.d directory -> Option C

4. Quick Check:

   init.groovy.d scripts run at startup [OK]

Hint: Use init.groovy.d scripts for startup automation [OK]

Common Mistakes:

• Trying manual commands only
• Editing config.xml directly (not recommended)
• Modifying Jenkins WAR file (complex and unsafe)