Triggers directive in Jenkins - Step-by-Step Execution

Process Flow - Triggers directive

Start Jenkins Job Configuration

↓

Add triggers directive

↓

Define trigger type

↓

Jenkins monitors trigger

↓

Trigger fires job

↓

Job runs automatically

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End

The triggers directive is added in Jenkins job config to tell Jenkins when to start the job automatically.

Execution Sample

Jenkins

pipeline {
  triggers {
    cron('H/15 * * * *')
  }
  stages {
    stage('Build') { steps { echo 'Building...' } }
  }
}

This Jenkins pipeline runs the build stage automatically every 15 minutes using the cron trigger.

Process Table

Step	Action	Trigger Evaluated	Result	Job Status
1	Start Jenkins job configuration	No trigger yet	Waiting for trigger	Idle
2	Add triggers directive with cron('H/15 * * * *')	Cron trigger set	Jenkins schedules job every 15 minutes	Idle
3	Time reaches scheduled cron time	Cron trigger fires	Job starts automatically	Running
4	Job executes build stage	N/A	Build stage runs and completes	Success
5	Wait for next cron time	Waiting	Job idle until next trigger	Idle

💡 Job waits idle until next scheduled cron trigger fires again

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
Job Status	Idle	Idle	Running	Success	Idle
Trigger State	None	Cron set	Fired	N/A	Waiting

Key Moments - 2 Insights

Why doesn't the job run immediately after adding the triggers directive?

Because the trigger only schedules the job to run at specific times (e.g., every 15 minutes). See execution_table step 2 and 3 where the job waits idle until the cron time.

What happens if the trigger condition is never met?

The job stays idle and never runs automatically. This is shown in execution_table step 5 where the job waits for the next trigger.

Visual Quiz - 3 Questions

Look at the execution table, what is the Job Status at Step 3 when the trigger fires?

A Success

B Idle

C Running

D Failed

💡 Hint

Check the 'Job Status' column at Step 3 in the execution_table.

At which step does the Jenkins job complete successfully?

A Step 4

B Step 2

C Step 3

D Step 5

💡 Hint

Look for 'Build stage runs and completes' in the 'Result' column.

If the cron trigger was removed, what would be the Job Status after Step 2?

A Running

B Idle

C Success

D Failed

💡 Hint

Without a trigger, the job waits idle. See 'Trigger State' in variable_tracker after Step 2.

Concept Snapshot

Triggers directive in Jenkins pipeline:
- Use triggers { cron('schedule') } to auto-start jobs
- Jenkins monitors triggers and runs jobs when conditions match
- Jobs stay idle until trigger fires
- Common triggers: cron, pollSCM, upstream
- Helps automate job runs without manual start

Full Transcript

The triggers directive in Jenkins pipeline is used to tell Jenkins when to start a job automatically. You add it inside the pipeline block under triggers. For example, cron('H/15 * * * *') schedules the job to run every 15 minutes. Jenkins watches the trigger and when the time matches, it fires the job. The job status changes from idle to running, then success after the build stage completes. If the trigger condition is not met, the job stays idle waiting. This automation helps run jobs on schedule without manual intervention.