Failing fast principle in Jenkins - Step-by-Step Execution

Process Flow - Failing fast principle

Start Pipeline

↓

Run Step 1

↓

Step 1 Success?

No→Fail Fast: Stop Pipeline

Yes↓

Run Step 2

↓

Step 2 Success?

No→Fail Fast: Stop Pipeline

Yes↓

Continue Steps or Finish

The pipeline runs steps one by one. If any step fails, it stops immediately to save time and resources.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        sh 'exit 1' // simulate failure
      }
    }
    stage('Test') {
      steps {
        sh 'echo "Test stage skipped due to Build failure"'
      }
    }
  }
}

This Jenkins pipeline has a Build stage that fails immediately ('exit 1'). The subsequent Test stage is skipped, demonstrating the fail fast principle.

Process Table

Step	Action	Result	Pipeline Status
1	Start pipeline	Pipeline started	Running
2	Run Build stage	Command 'exit 1' executed	Running
3	Check Build result	Failure detected	Fail Fast: Pipeline stopped
4	No further stages run	Pipeline terminated early	Stopped

💡 Build stage failed, so pipeline stopped immediately due to fail fast principle

Status Tracker

Variable	Start	After Step 1	After Step 2	Final
pipeline_status	Not started	Running	Running	Stopped
build_stage_result	Not run	Failure	Not run	Failure

Key Moments - 2 Insights

Why does the pipeline stop immediately after the build stage fails?

Because of the fail fast principle, the pipeline stops at the first failure to avoid wasting time on later steps. See execution_table row 3.

What happens if the build stage succeeds?

If the build stage succeeds, the pipeline continues to the next stages. This is shown by the 'Yes' path in the concept_flow.

Visual Quiz - 3 Questions

Look at the execution table, what is the pipeline status after step 2?

A Running

B Stopped

C Failed but continuing

D Not started

💡 Hint

Check the 'Pipeline Status' column at step 2.

At which step does the pipeline detect failure and stop?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look at the 'Result' column where failure is detected and pipeline stops.

If the build command was 'exit 0' instead of 'exit 1', what would happen?

A Pipeline stops immediately

B Pipeline fails later

C Pipeline continues to next stages

D Pipeline status is unknown

💡 Hint

Refer to the concept_flow where success leads to continuing the pipeline.

Concept Snapshot

Failing Fast Principle in Jenkins Pipeline:
- Pipeline runs stages sequentially.
- If any stage fails, pipeline stops immediately.
- Saves time and resources by not running unnecessary steps.
- Use 'exit 1' in shell to simulate failure.
- Helps catch errors early and fix quickly.

Full Transcript

The failing fast principle means stopping a Jenkins pipeline as soon as a failure happens. The pipeline starts and runs the first stage. If the stage succeeds, it moves on. If it fails, like with 'exit 1' command, the pipeline stops immediately. This saves time by not running later steps that depend on success. The execution table shows the pipeline starting, running the build stage, detecting failure, and stopping. Variables track the pipeline status changing from running to stopped. This principle helps catch problems early and avoid wasting resources.