Azure Pipelines overview - Step-by-Step Execution

Process Flow - Azure Pipelines overview

Code Commit Trigger

↓

Pipeline Starts

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Build Stage

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Test Stage

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Deploy Stage

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Pipeline Ends

This flow shows how Azure Pipelines runs automatically when code is committed, then builds, tests, and deploys the application step-by-step.

Execution Sample

Azure

trigger:
  - main

pool:
  vmImage: 'ubuntu-latest'

steps:
  - script: echo Hello, Azure Pipelines!

This pipeline triggers on commits to main, runs on an Ubuntu VM, and prints a greeting message.

Process Table

Step	Action	Evaluation	Result
1	Detect commit on 'main' branch	Commit on 'main'?	Yes, pipeline triggered
2	Allocate VM from pool 'ubuntu-latest'	VM available?	VM allocated
3	Run script step	Execute 'echo Hello, Azure Pipelines!'	Output: Hello, Azure Pipelines!
4	Complete pipeline	All steps done?	Pipeline succeeded

💡 Pipeline ends after all steps complete successfully

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
Pipeline Status	Not started	Triggered	Running	Running	Succeeded
VM Status	None	None	Allocated	Allocated	Released
Script Output	None	None	None	Hello, Azure Pipelines!	Hello, Azure Pipelines!

Key Moments - 3 Insights

Why does the pipeline start only when code is committed to 'main'?

Because the trigger is set to the 'main' branch, as shown in execution_table row 1, so only commits there start the pipeline.

What happens if the VM is not available?

The pipeline would wait or fail at step 2 in execution_table because it cannot allocate the VM to run the steps.

Why is the script output important?

It shows the pipeline ran the commands correctly, as seen in execution_table step 3 and variable_tracker Script Output.

Visual Quiz - 3 Questions

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

A Triggered

B Running

C Succeeded

D Not started

💡 Hint

Check the 'Pipeline Status' row in variable_tracker after Step 2

At which step does the pipeline print 'Hello, Azure Pipelines!'?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Script Output' in variable_tracker and execution_table step 3

If the trigger was changed to 'develop' branch, what would happen?

A Pipeline triggers on all branches

B Pipeline triggers on commits to 'main' branch

C Pipeline triggers on commits to 'develop' branch

D Pipeline never triggers

💡 Hint

Refer to execution_table step 1 about branch triggers

Concept Snapshot

Azure Pipelines run automatically on code commits.
They use a VM to build, test, and deploy.
Triggers specify which branch starts the pipeline.
Steps run in order: build, test, deploy.
Pipeline status updates as steps complete.

Full Transcript

Azure Pipelines start when code is committed to a specified branch, like 'main'. The pipeline allocates a virtual machine to run tasks. It runs steps such as building the code, testing it, and deploying the application. Each step updates the pipeline status. The example pipeline prints a message to show it ran successfully. If the VM is unavailable, the pipeline waits or fails. Changing the trigger branch changes when the pipeline runs.

Practice

1. What is the main purpose of Azure Pipelines?

easy

A. To automate building, testing, and deploying code

B. To store large amounts of data

C. To create virtual machines

D. To monitor network traffic

Solution

1. Step 1: Understand Azure Pipelines role

   Azure Pipelines automate the process of building, testing, and deploying code changes.

2. Step 2: Compare options with purpose

   Options B, C, and D describe other Azure services, not pipelines.

3. Final Answer:

   To automate building, testing, and deploying code -> Option A

4. Quick Check:

   Azure Pipelines = automate build/test/deploy [OK]

Hint: Remember pipelines automate code workflows [OK]

Common Mistakes:

• Confusing pipelines with storage services
• Thinking pipelines create virtual machines
• Mixing pipelines with monitoring tools

2. Which file format is commonly used to define Azure Pipelines?

easy

A. .json

B. .txt

C. .xml

D. .yaml

Solution

1. Step 1: Identify pipeline definition format

   Azure Pipelines use YAML files to define build and deployment steps.

2. Step 2: Eliminate other formats

   JSON, XML, and TXT are not standard for pipeline definitions in Azure.

3. Final Answer:

   .yaml -> Option D

4. Quick Check:

   Pipeline config = YAML file [OK]

Hint: YAML files define pipeline steps clearly [OK]

Common Mistakes:

• Choosing JSON instead of YAML
• Confusing XML with pipeline config
• Thinking plain text files define pipelines

3. Given this YAML snippet in an Azure Pipeline:

trigger:
  branches:
    include:
      - main

steps:
- script: echo Hello, world!

What happens when you push code to the main branch?

medium

A. The pipeline fails due to syntax error

B. The pipeline ignores the push

C. The pipeline runs and prints 'Hello, world!'

D. The pipeline runs but does nothing

Solution

1. Step 1: Understand trigger configuration

   The pipeline triggers on pushes to the 'main' branch as specified.

2. Step 2: Analyze steps section

   The single step runs a script that echoes 'Hello, world!'.

3. Final Answer:

   The pipeline runs and prints 'Hello, world!' -> Option C

4. Quick Check:

   Trigger on main runs echo script [OK]

Hint: Trigger on branch runs defined script [OK]

Common Mistakes:

• Assuming pipeline ignores main branch
• Thinking pipeline does nothing on trigger
• Believing syntax error exists in snippet

4. You wrote this YAML for Azure Pipelines but it never triggers:

trigger:
  branches:
    exclude:
      - main

steps:
- script: echo Build started

What is the likely problem?

medium

A. The pipeline excludes the main branch, so pushes to main don't trigger it

B. The script syntax is incorrect

C. The trigger keyword is misspelled

D. The pipeline requires a separate build agent

Solution

1. Step 1: Review trigger exclude setting

   The pipeline excludes the 'main' branch, so pushes to 'main' won't start it.

2. Step 2: Check other parts

   The script syntax and trigger keyword are correct; no build agent issue is indicated.

3. Final Answer:

   The pipeline excludes the main branch, so pushes to main don't trigger it -> Option A

4. Quick Check:

   Exclude main branch stops trigger [OK]

Hint: Exclude means branch won't trigger pipeline [OK]

Common Mistakes:

• Thinking script syntax is wrong
• Assuming trigger keyword typo
• Believing build agent is missing

5. You want to run tests only when code is pushed to the develop branch and deploy only when code is pushed to main. How should you configure triggers in your Azure Pipelines YAML?

hard

A. Use a single pipeline triggered on both branches and run all steps always

B. Use two separate pipelines: one triggered on 'develop' for tests, another on 'main' for deploy

C. Trigger only on 'main' and manually run tests

D. Trigger only on 'develop' and deploy manually

Solution

1. Step 1: Understand branch-specific triggers

   Running tests and deploy on different branches requires separate triggers.

2. Step 2: Choose pipeline structure

   Two pipelines allow independent triggers and steps per branch, matching requirements.

3. Step 3: Evaluate other options

   Single pipeline running all steps always doesn't separate concerns; manual runs reduce automation benefits.

4. Final Answer:

   Use two separate pipelines: one triggered on 'develop' for tests, another on 'main' for deploy -> Option B

5. Quick Check:

   Separate pipelines for branch-specific tasks [OK]

Hint: Separate pipelines for different branch tasks [OK]

Common Mistakes:

• Using one pipeline for all branches without conditions
• Triggering only on main and skipping tests automation
• Triggering only on develop and missing deploy automation