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Documentation

Comprehensive documentation is the backbone of operational excellence in DevOps and SRE practices. Good documentation enables teams to troubleshoot quickly, onboard new members efficiently, maintain consistency, and preserve institutional knowledge. This chapter covers documentation types, tools, standards, templates, and best practices for creating and maintaining technical documentation in production environments.


┌─────────────────────────────────────────────────────────────────────────┐
│ DOCUMENTATION TYPES │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ TECHNICAL DOCUMENTATION │ │
│ ├─────────────────────────────────────────────────────────────────┤ │
│ │ │ │
│ │ ┌──────────────────┐ ┌──────────────────┐ │ │
│ │ │ Architecture │ │ Runbooks │ │ │
│ │ │ Docs │ │ │ │ │
│ │ ├──────────────────┤ ├──────────────────┤ │ │
│ │ │ System design │ │ Operations │ │ │
│ │ │ Network topology │ │ procedures │ │ │
│ │ │ Data flows │ │ Troubleshooting │ │ │
│ │ │ Dependencies │ │ Emergency │ │ │
│ │ │ Components │ │ response │ │ │
│ │ └──────────────────┘ └──────────────────┘ │ │
│ │ │ │
│ │ ┌──────────────────┐ ┌──────────────────┐ │ │
│ │ │ Post-mortems │ │ API Docs │ │ │
│ │ │ │ │ │ │ │
│ │ ├──────────────────┤ ├──────────────────┤ │ │
│ │ │ Incident reports │ │ Endpoints │ │ │
│ │ │ Root cause │ │ Authentication │ │ │
│ │ │ analysis │ │ Examples │ │ │
│ │ │ Lessons learned │ │ Error codes │ │ │
│ │ │ Action items │ │ Rate limits │ │ │
│ │ └──────────────────┘ └──────────────────┘ │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
│ Documentation Hierarchy: │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ │ │
│ │ Strategy (Why) → High-level goals, decisions │ │
│ │ │ │
│ │ Architecture (What) → System design, components │ │
│ │ │ │
│ │ Operations (How) → Procedures, runbooks │ │
│ │ │ │
│ │ Reference (Info) → APIs, configs, code │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘

Terminal window
# ============================================================
# DOCUMENTATION TOOLS
# ============================================================
# Static Site Generators
- Hugo # Fast, Go-based
- Gatsby # React-based, GraphQL
- Jekyll # Ruby, GitHub Pages native
- Docusaurus # React, documentation-focused
- MkDocs # Markdown-based, Python
# Wiki Platforms
- Confluence # Enterprise, Atlassian
- Notion # All-in-one workspace
- Bookstack # Open source, self-hosted
- Wiki.js # Modern, Node.js
# Diagram Tools
- PlantUML # Text-based diagrams
- Mermaid # Markdown diagrams
- Draw.io # GUI-based
- Excalidraw # Hand-drawn style
# Code Documentation
- Javadoc # Java
- Sphinx # Python
- Doxygen # Multi-language
- ESDoc # JavaScript/TypeScript
# Version Control
- GitHub # Markdown, Git-based
- GitLab # GitLab Pages
- AWS CodeCommit # AWS native

# Service Runbook: [Service Name]
## Metadata
- **Owner**: [Team Name] <team@company.com>
- **Slack Channel**: #team-support
- **On-Call**: PagerDuty [link]
- **Tier**: [1/2/3]
## Service Description
[Brief description of what this service does]
## Architecture
[Link to architecture diagram]
## Dependencies
| Service | Type | Critical |
|---------|------|----------|
| Database | PostgreSQL | Yes |
| Cache | Redis | No |
| API | REST | Yes |
## Monitoring
### Dashboards
- [Grafana Dashboard](link)
- [Datadog Dashboard](link)
### Alerts
| Alert | Threshold | Action |
|-------|-----------|--------|
| High Error Rate | > 5% | Check logs |
| High Latency | p99 > 2s | Check traces |
| Memory | > 80% | Scale or investigate |
## Endpoints
| Path | Description |
|------|-------------|
| /health | Health check |
| /metrics | Prometheus metrics |
## Deployment
### Prerequisites
- [ ] Access to CI/CD
- [ ] Deployment approval
### Steps
1. Merge to main branch
2. Wait for CI pipeline
3. Verify deployment in staging
4. Deploy to production
5. Check health endpoints
6. Verify monitoring
### Rollback
```bash
# Quick rollback command
./deploy.sh rollback --service=myapp

Or use CI/CD dashboard to redeploy previous version.

SymptomLikely CauseResolution
502 errorsBackend downCheck pods
High latencyDatabase queryCheck slow logs
OOM crashesMemory leakRestart service
---
## 97.4 Architecture Documentation
### Example Template
```markdown
# System Architecture: [System Name]
## Overview
[Brief high-level description]
## Goals
- [Goal 1]
- [Goal 2]
## Non-Goals
- [What we're NOT solving]
## Architecture Diagram
[Insert Mermaid/PlantUML diagram]
## Components
### Component A
- **Purpose**: [What it does]
- **Technology**: [Stack]
- **Scaling**: [Horizontal/Vertical]
- **Data**: [Storage, backup]
### Component B
- **Purpose**: [What it does]
- **Technology**: [Stack]
## Data Flow
1. [Step 1]
2. [Step 2]
3. [Step 3]
## Security
- Authentication: [Method]
- Authorization: [Method]
- Encryption: [At rest/In transit]
## Failure Modes
| Scenario | Impact | Mitigation |
|----------|--------|------------|
| Database down | Service unavailable | Retry logic, fallback |
| Network partition | Partial failure | Circuit breaker |
## Monitoring
- [Metrics links]
- [Logging links]
- [Tracing links]
## Decisions
| Date | Decision | Rationale |
|------|----------|-----------|
| 2024-01 | Chose PostgreSQL | ACID compliance needed |

┌─────────────────────────────────────────────────────────────────────────┐
│ DOCUMENTATION BEST PRACTICES │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ 1. WRITE DOCS LIKE CODE │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ • Version control in Git │ │
│ │ • Code review for docs │ │
│ │ • Automated builds/deployments │ │
│ │ • Test documentation links │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
│ 2. DOCUMENT THE WHY │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ • Not just what, but why decisions were made │ │
│ │ • Include context for future maintainers │ │
│ │ • Link to RFCs and discussions │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
│ 3. KEEP IT CURRENT │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ • Review docs regularly │ │
│ │ • Automate updates where possible │ │
│ │ • Mark stale docs clearly │ │
│ │ • Delete obsolete content │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
│ 4. MAKE IT ACCESSIBLE │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ • Searchable │ │
│ │ • Consistent structure │ │
│ │ • Link to related docs │ │
│ │ • Version alongside code │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
│ 5. START SIMPLE │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ • Minimum viable documentation │ │
│ │ • Add detail iteratively │ │
│ │ • Iterative improvement │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────────────┐
│ DOCUMENTATION INTERVIEW QUESTIONS │
├─────────────────────────────────────────────────────────────────────────┤
Q1: What types of documentation should a service have? │
A1: │
- Architecture documentation │
- Runbooks for operations │
- API documentation │
- Post-mortems │
- Onboarding guides │
- Security documentation │
─────────────────────────────────────────────────────────────────────────┤
Q2: How do you keep documentation up to date? │
A2: │
- Version control with code │
- Include docs in code review │
- Automated deployment │
- Regular documentation audits │
- Assign ownership to teams │
- Link docs to code (source of truth) │
─────────────────────────────────────────────────────────────────────────┤
Q3: What makes a good runbook? │
A3: │
- Clear ownership │
- Step-by-step procedures │
- Troubleshooting table │
- Monitoring links │
- Rollback procedures │
- Emergency contacts │
- Links to source code │
─────────────────────────────────────────────────────────────────────────┤
Q4: How do you document architecture decisions? │
A4: │
- Use ADRs (Architecture Decision Records) │
- Include context and rationale │
- Document alternatives considered │
- Link to RFCs/proposals │
- Include diagrams │
─────────────────────────────────────────────────────────────────────────┤
Q5: What tools do you use for documentation? │
A5: │
- Git-based (Markdown) for technical docs │
- Mermaid/PlantUML for diagrams │
- Static site generators (MkDocs, Hugo) │
- API tools (Swagger, OpenAPI) │
- Wiki for team knowledge │
─────────────────────────────────────────────────────────────────────────┤
Q6: How do you handle documentation for microservices? │
A6: │
- Each service owns its docs │
- Central index/link repository │
- Consistent templates │
- Service catalog with links │
- Shared components documented once │
─────────────────────────────────────────────────────────────────────────┤
Q7: What is a post-mortem and what should it include? │
A7: │
- What happened │
- Impact │
- Root cause │
- Timeline │
- What went well │
- What could improve │
- Action items │
- Blameless focus │
─────────────────────────────────────────────────────────────────────────┤
Q8: How do you measure documentation quality? │
A8: │
- Usage metrics (views, searches) │
- Staleness indicators │
- Feedback from users │
- Time to onboard new engineers │
- Reduction in questions │
- Accuracy (errors found) │
└─────────────────────────────────────────────────────────────────────────┘

  • Types: Architecture, Runbooks, Post-mortems, API Docs
  • Tools: Markdown, MkDocs, Mermaid, Git-based
  • Runbook: Owner, troubleshooting, deployment, rollback
  • Best Practices: Keep current, version control, automate

Chapter 98: Change Management


Last Updated: February 2026