Feature Flags, System Monitoring, and Developer Experience — Learning Roadmap¶

This roadmap is your study plan. Work through the phases in order. Each phase builds directly on the previous one. Mark your current position with ← You Are Here and update it as you progress.

Prerequisites Map¶

Confirm you have working knowledge of these before entering Phase 1:

[[django-fastapi-flask]]       ──┐
                                  ├──► Feature Flags & Monitoring  (start here)
[[devops-platform-engineering]] ──┤
                                  │
[[systems-architecture]]        ──┘

If any prerequisite is missing, complete it first and return here.

Learning Path Visualization¶

flowchart TD
    A([Prerequisites Met]) --> B

    subgraph P1["Phase 1: Foundation  •  Weeks 1–3"]
        B["Module 01: Introduction to Observability"]
        B --> C["Module 02: Metrics and Prometheus"]
        C --> D["Module 03: Dashboards and Grafana"]
    end

    subgraph P2["Phase 2: Core Toolchain  •  Weeks 4–7"]
        E["Module 04: Error Tracking with Sentry"]
        E --> F["Module 05: Distributed Tracing"]
        F --> G["Module 06: PostHog Product Analytics"]
        G --> H["Module 07: DataDog APM"]
    end

    subgraph P3["Phase 3: Production Patterns  •  Weeks 8–11"]
        I["Module 08: Feature Flags Deep Dive"]
        I --> J["Module 09: Progressive Delivery"]
        J --> K["Module 10: Incident Response"]
        K --> L["Module 11: Developer Experience"]
    end

    subgraph P4["Phase 4: Mastery  •  Weeks 12–16"]
        M["Module 12: Capstone Project"]
        M --> N["Topic Review & Weak-Spot Work"]
        N --> O([Topic Complete])
    end

    D --> E
    H --> I
    L --> M

    style A fill:#2a9d8f,color:#fff,stroke:none
    style O fill:#2a9d8f,color:#fff,stroke:none
    style P1 fill:#edf2fb,stroke:#8d99ae
    style P2 fill:#fef3c7,stroke:#d97706
    style P3 fill:#fee2e2,stroke:#dc2626
    style P4 fill:#dcfce7,stroke:#16a34a

Phase Breakdown¶

Phase 1: Foundation¶

Goal: Understand what observability means, why it exists, and get comfortable with Prometheus metrics and Grafana dashboards. Leave Phase 1 able to instrument a simple application and visualize its health.

Phase 1 Exit Criteria:

• Can explain the three pillars of observability without notes
• Have instrumented a Python application with at least 3 Prometheus metrics
• Have built a Grafana dashboard with 3+ panels and one alert rule
• Scored ≥ 70% on Modules 01, 02, and 03 tests
• GLOSSARY.md has at least 10 entries

Milestone unlocked: Foundation Built

Phase 2: Core Toolchain¶

Goal: Develop hands-on fluency with the major observability tools. Leave Phase 2 able to set up error tracking, distributed tracing, product analytics, and APM in a real application.

Phase 2 Exit Criteria:

• Have set up Sentry in a Python or JS app and triaged a real error
• Have propagated a trace across two services with OpenTelemetry
• Have created a PostHog funnel and interpreted drop-off data
• Scored ≥ 75% on all Phase 2 module tests

Milestone unlocked: Core Toolchain Mastery

Phase 3: Production Patterns¶

Goal: Apply knowledge to production engineering challenges. Feature flags, progressive delivery, incident response, and DX measurement require synthesizing concepts from all earlier phases.

Phase 3 Exit Criteria:

• Have implemented a gradual rollout using feature flags (5% → 25% → 100%)
• Have written a runbook for a realistic failure scenario
• Have calculated DORA metrics for a team or project
• Scored ≥ 80% on all Phase 3 module tests

Milestone unlocked: Production Patterns Mastery

Phase 4: Mastery¶

Goal: Synthesize everything. Build a fully-instrumented multi-service application with a complete observability stack, runbooks, SLO dashboard, and feature flag system.

Phase 4 Exit Criteria:

• Capstone project complete and documented in PROJECTS.md
• Overall topic score ≥ 80%
• CHEATSHEET.md is complete and genuinely useful as a reference
• GLOSSARY.md has definitions for every term encountered throughout the topic

Milestone unlocked: Topic Mastery

Time Estimates Summary¶

[!NOTE] These estimates assume roughly 5–8 focused hours per week. If you're studying part-time, the calendar weeks will stretch accordingly. Adjust the schedule to fit your life — consistency matters more than pace.

Milestone Definitions¶

Alternative Paths¶

Fast Track (If You Have Prior Experience)¶

If you already have solid experience with Prometheus and Grafana:

Skim Modules 01–03 → Start at Module 04 → Continue normally

Take the Module 01 test first. If you score ≥ 85%, skip to Module 04.

Deep Dive Path (Maximum Understanding)¶

For maximum depth, add these supplementary activities between phases:

• After Phase 1: Read the Google SRE Book, Chapters 1–6 (error budgets, SLOs) — sre.google/sre-book
• After Phase 2: Work through the OpenTelemetry demo application — opentelemetry.io/docs/demo
• After Phase 3: Read the DORA State of DevOps Report for the current year

Project-First Path (Learn by Building)¶

If you learn best by doing rather than reading:

Module 01 → Beginner Project → Module 02 → Beginner Project → Module 03 → ...

Alternate one module of theory with one hands-on project at each step.

You Are Here¶

Current Phase: Not started

Current Module: None — begin at Module 01

Last Completed Module: None

Next Action: Open Module 01 and read the Overview section.

Update this section each time you advance to a new module or phase.