DevOps Concepts

 

In Azure DevOps Pipelines, the structure is hierarchical. Diagram shows the typical flow:

Trigger → Pipeline → Stage → Job (runs on Agent) → Steps (Script/Task)

1️⃣ Stages

A Stage is a major phase of the pipeline.

Typical stages represent different parts of the CI/CD lifecycle.

Examples:

• Build

• Test

• Deploy

stages: YAML

- stage: Build

- stage: Test

- stage: Deploy

2️⃣ Agents

An Agent is the machine that runs your pipeline jobs.

It executes the tasks like:

• compiling code

• running scripts

• deploying applications

Agents can be:

Microsoft-hosted agents

Provided by Microsoft.

Example:

• Ubuntu

• Windows

• macOS

Self-hosted agents

Your own machines or servers.

Example:

• company build server

• private VM

Example

pool:
  vmImage: 'ubuntu-latest'

Here Ubuntu is the agent machine that executes the pipeline.

---

3️⃣ Jobs

A Job is a group of steps executed on one agent.

Important rules:

• Each job runs on one agent

• Jobs can run in parallel

• Jobs contain steps

Example

jobs:
- job: BuildJob
  steps:

So the hierarchy becomes:

Stage
   └── Job
         └── Steps

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4️⃣ Steps

A Step is the smallest unit of work in a pipeline.

Steps can be:

Script

Run shell commands.

Example:

- script: ls -l

Task

Pre-built Azure DevOps task.

Examples:

• Publish build artifact

• Deploy to Azure App Service

• Invoke REST API

Example:

- task: AzureWebApp@1

So steps perform the actual work.

---

5️⃣ Full Example Pipeline

Example combining everything:

trigger:
- main

stages:
- stage: Build
  jobs:
  - job: BuildJob
    pool:
      vmImage: ubuntu-latest
    steps:
    - script: npm install
    - script: npm run build

- stage: Deploy
  jobs:
  - job: DeployJob
    steps:
    - task: AzureWebApp@1

---

6️⃣ How Your Diagram Maps to Azure DevOps

From your image:

Diagram Element	Azure DevOps Concept
Trigger	Pipeline trigger (commit, PR, schedule)
Pipeline	Entire CI/CD workflow
Stage	Build / Test / Deploy phases
Agent	Machine executing the job
Job	Unit executed on an agent
Step	Script or Task

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7️⃣ Simple Real-World Analogy

Imagine building a car 🚗

Concept	Example
Pipeline	Build a car
Stage	Assemble → Test → Deliver
Job	Install engine
Agent	Worker
Step	Tighten bolt

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✅ Simple hierarchy to remember

Pipeline
   └── Stage
        └── Job
             └── Steps