Day 77 – Remote Triggers in Jenkins

On Day 77 of my DevOps Journey, I explored how to trigger Jenkins jobs remotely. This is a crucial feature in CI/CD pipelines when you want external systems (like GitHub, GitLab, or custom scripts) to start Jenkins jobs automatically without manual intervention.

Today, I’ll document the step-by-step guide for setting up remote job triggers using tokens, API tokens, and Jenkins Crumb issuers.

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🔧 Step 1 – Enable Remote Trigger in Job

1. Go to Jenkins Job → Configure.

2. Under Build Triggers, check ✅ Trigger builds remotely.

3. Provide a token name (example: testtoken).

4. Save the configuration.

5. Jenkins generates a Job URL with token:

    http://<JENKINS_IP>:8080/job/<JOB_NAME>/build?token=testtoken
   

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🔧 Step 2 – Generate API Token for User

1. Click your username (top right corner in Jenkins).

2. Select Configure → API Token → Generate.

3. Save the generated API token securely.

    Example: admin:116ce8f1ae914b477d0c74a68ffcc9777c
   

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🔧 Step 3 – Generate Jenkins Crumb

Jenkins requires a crumb (CSRF protection token) for API requests.

1. Install wget (on Git Bash for Windows).
   Place the binary in c:/program files/Git/mingw64/bin.

2. Run this command (replace with your username, password, Jenkins URL):

    wget -q --auth-no-challenge --user username --password password \
    --output-document - \
    'http://<JENKINS_IP>:8080/crumbIssuer/api/xml?xpath=concat(//crumbRequestField,":",//crumb)'
   

3. Example output:

    Jenkins-Crumb:8cb80f4f56d6d35c2121a1cf35b7b501
   

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🔧 Step 4 – Trigger Jenkins Job via cURL

Now we have:

• Jenkins Job URL with token

• API Token

• Crumb

Use this command:

curl -I -X POST \
  http://username:APITOKEN@<JENKINS_IP>:8080/job/<JOB_NAME>/build?token=TOKENNAME \
  -H "Jenkins-Crumb:CRUMB"

✅ Example:

curl -I -X POST \
  http://admin:110305ffb46e298491ae082236301bde8e@52.15.216.180:8080/job/vprofile-Code-Analysis/build?token=testtoken \
  -H "Jenkins-Crumb:8cb80f4f56d6d35c2121a1cf35b7b501"

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🎯 Why This Is Important

• Enables automation between services (GitHub → Jenkins, monitoring alerts → Jenkins, etc.).

• Provides security with tokens and crumbs.

• Makes Jenkins more integrated with external systems.

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📌 Key Takeaways

• Always secure your tokens – never expose them in plaintext.

• Remote triggers are powerful for event-driven CI/CD pipelines.

• API tokens + crumbs ensure both authentication and protection from CSRF attacks.