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🎯 Exam Strategy

Study Order (by weight)

████████████████  Domain 3: Build & Release Pipelines   (50-55%)  ← Start here!
████              Domain 1: Processes & Communications  (10-15%)
████              Domain 2: Source Control Strategy     (10-15%)
████              Domain 4: Security & Compliance       (10-15%)
██                Domain 5: Instrumentation Strategy    (5-10%)

Exam Tips

⏱️ Time management: ~180 minutes for ~50–60 questions → ~3 min/question
📋 Read the question twice: Many answers hinge on a single word (e.g., “cheapest”, “fastest rollback”, “without code changes”)
🎯 “Most appropriate”: When multiple answers seem correct, pick the Azure-native solution
🔄 Case studies: Read the requirements section first, then answer questions
❓ Mark for review: Don’t spend more than 5 minutes on any single question
💡 Elimination: Remove obviously wrong answers first

Common Traps

Trap	Watch Out For
Classic vs YAML pipelines	YAML is the modern answer unless “Classic” is specified
Managed Identity vs Service Principal	When on Azure → Managed Identity; external → Service Principal
Blue-green vs Canary	Blue-green = instant rollback; Canary = gradual rollout
Git revert vs Git reset	`revert` = safe for shared branches; `reset` = local only
Lead time vs Cycle time	Lead = full journey; Cycle = active work only
ARM Complete vs Incremental	Complete DELETES resources not in template

📋 Master Cheat Sheet

GitHub Flow (6 steps)

1. Branch → 2. Commit → 3. PR → 4. Review → 5. Deploy → 6. Merge

Deployment Strategies Summary

DORA Metrics

Key Azure Services for AZ-400

Versioning Quick Reference

SemVer:  MAJOR.MINOR.PATCH  (1.4.2)
         ^     ^     ^
         │     │     └── Bug fixes
         │     └──────── New features (backwards-compatible)
         └────────────── Breaking changes

CalVer:  YYYY.MM.PATCH  (2024.07.1)

Branch Merging Strategies

Git Emergency Commands

git reflog                          # Show all HEAD history
git reset --soft HEAD~1             # Undo commit, keep changes staged
git reset --hard HEAD~1             # Undo commit, discard changes (DANGEROUS)
git revert <sha>                    # Safe undo (creates new commit)
git cherry-pick <sha>               # Apply single commit to current branch
git stash / git stash pop           # Temporarily store changes

Key YAML Pipeline Concepts

trigger: [main]                    # CI trigger
pr: [main]                         # PR trigger
schedules:                         # Scheduled trigger
  - cron: '0 2 * * 1-5'
  
dependsOn: StageA                  # Stage dependency
condition: succeeded('StageA')     # Conditional execution
concurrency:                       # Concurrency control
  group: production
  cancelInProgress: false

strategy:
  matrix: {...}                    # Matrix build
  rolling:                         # Rolling deployment
    maxParallel: 25%

KQL Quick Reference

requests                           -- Application Insights requests
| where timestamp > ago(1h)        -- Time filter
| where success == false           -- Filter failed
| summarize count() by name        -- Group by
| summarize avg(duration) by bin(timestamp, 1h)  -- Time bucket
| order by count_ desc             -- Sort
| take 20                          -- Limit
| render timechart                 -- Visualize
| project name, duration, success  -- Select columns
| extend durationSec = duration/1000  -- Computed column

Managed Identity vs Service Principal

On Azure resource calling Azure service?
  └── YES → Managed Identity (no secret to manage!)
       ├── Same resource → System-assigned
       └── Multiple resources → User-assigned

External service / multi-tenant / outside Azure?
  └── NO → Service Principal
       ├── Modern: OIDC / Workload Identity Federation (no secret!)
       └── Legacy: Client Secret or Certificate

GitHub Auth Quick Reference

Same repo Actions workflow  → GITHUB_TOKEN (automatic)
Cross-repo / org-wide      → GitHub App (recommended) or Fine-grained PAT
Third-party integration     → GitHub App
User-specific scripts       → Fine-grained PAT (with expiry)

Security Scanning Tools

🔗 Official Documentation Links

Azure DevOps

GitHub

Azure Services

Exam Resources

📅 Suggested Study Plan (4 Weeks)

Week 1 — Pipelines Foundations (50% of exam)

Read Domain 3 Overview
Study 3c: Pipelines (YAML)
Study 3d: Deployments
Hands-on: Create a multi-stage YAML pipeline in Azure DevOps
Hands-on: Set up a GitHub Actions workflow with environments and approvals

Week 2 — Pipelines Advanced + Security

Study 3a: Package Management
Study 3b: Testing Strategy
Study 3e: Infrastructure as Code
Study 3f: Maintain Pipelines
Study Domain 4: Security & Compliance
Hands-on: Create a Bicep template and deploy via pipeline
Hands-on: Enable GHAS and run CodeQL on a repo

Week 3 — Processes, Source Control, Instrumentation

Study Domain 1: Processes & Communications
Study Domain 2: Source Control Strategy
Study Domain 5: Instrumentation
Hands-on: Set up Azure Boards with GitHub integration
Hands-on: Write KQL queries in Log Analytics

Week 4 — Review and Practice

Take free practice assessment (aim for 75%+)
Review weak areas using these notes
Review Cheat Sheet above
Take practice assessment again (aim for 85%+)
Book and take the exam! 🎓

✅ Pre-Exam Checklist

Knowledge checks:

Can I write a multi-stage Azure Pipelines YAML from scratch?
Can I explain Blue-Green vs Canary vs Rolling deployments?
Do I know when to use Managed Identity vs Service Principal?
Can I explain the difference between Lead Time and Cycle Time?
Do I know at least 5 basic KQL operators?
Can I explain trunk-based development vs Git Flow?
Do I know what GitHub Advanced Security components are?
Can I describe 3 ways to prevent secret leakage in pipelines?

Practical experience:

Created a CI/CD pipeline in Azure DevOps
Used GitHub Actions for automated deployment
Set up branch policies and PR workflows
Deployed a Bicep template to Azure
Queried Application Insights with KQL
Configured at least one security scan in a pipeline

← 05 - Instrumentation Strategy

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