Stage block structure in Jenkins - Step-by-Step Execution

Process Flow - Stage block structure

Start Pipeline

↓

Enter stages block

↓

Execute stage 1

↓

Execute stage 2

↓

... more stages ...

↓

Exit stages block

↓

End Pipeline

The pipeline starts, enters the stages block, executes each stage in order, then exits the stages block and ends.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Build') {
      steps { echo 'Building...' }
    }
  }
}

This pipeline runs one stage named 'Build' that prints 'Building...'.

Process Table

Step	Block Entered	Action	Output	Next Step
1	pipeline	Start pipeline execution	Pipeline started	Enter stages block
2	stages	Enter stages block	Ready to run stages	Enter stage 'Build'
3	stage('Build')	Run steps block	Prints: Building...	Exit stage 'Build'
4	stage('Build')	Exit stage block	Stage 'Build' complete	Exit stages block
5	stages	Exit stages block	All stages complete	End pipeline
6	pipeline	End pipeline execution	Pipeline finished	Stop

💡 All stages executed, pipeline ends normally

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
pipeline_state	Not started	Running	Running	Running	Finished
current_block	None	stages	stage('Build')	stages	None
stage_status	None	Pending	Running	Complete	Complete

Key Moments - 2 Insights

Why does the pipeline enter the 'stages' block before running any stage?

The 'stages' block groups all stages together. Execution must enter it first to know which stages to run, as shown in step 2 of the execution table.

What happens if there are multiple stages inside the 'stages' block?

Each stage runs one after another inside the 'stages' block. The pipeline enters each stage block in order, runs its steps, then moves to the next stage, similar to step 3 and 4.

Visual Quiz - 3 Questions

Look at the execution table, what is the 'current_block' after step 3?

A stages

B pipeline

C stage('Build')

D None

💡 Hint

Check the 'current_block' column in variable_tracker after step 3

At which step does the pipeline finish execution?

A Step 5

B Step 6

C Step 4

D Step 3

💡 Hint

Look at the 'pipeline_state' variable in variable_tracker and the 'Action' column in execution_table

If a second stage is added after 'Build', what will happen after step 4?

A Next stage block starts executing

B Stages block exits

C Pipeline ends immediately

D Pipeline restarts

💡 Hint

Refer to the concept_flow and execution_table steps for multiple stages

Concept Snapshot

pipeline {
  agent any
  stages {
    stage('Name') {
      steps { ... }
    }
  }
}

- 'stages' groups multiple 'stage' blocks
- Each 'stage' runs sequentially
- Steps inside 'stage' execute commands
- Pipeline ends after all stages complete

Full Transcript

The Jenkins pipeline starts by entering the pipeline block. Inside it, the stages block groups all stages. The pipeline enters the stages block, then executes each stage one by one. For each stage, it runs the steps defined inside. After finishing all stages, the pipeline exits the stages block and ends. Variables like current_block and stage_status track which part is running. This structure helps organize tasks clearly and run them in order.