The Five Levels

Chaos engineering maturity progresses through five levels. Most organizations start at Level 1. Reaching Level 3 provides significant reliability improvements. Levels 4-5 represent industry-leading practices.

Level 1: Ad-Hoc (Reactive)

Characteristics:
- Chaos experiments happen only after major incidents ("this should never happen again")
- No formal process or tooling
- Experiments are manual and unrepeatable
- Only infrastructure team participates
- Testing only in non-production environments

How to progress: Pick one critical service and run a single, planned experiment with documented hypothesis and results.

Level 2: Planned (Exploratory)

Characteristics:
- Scheduled game days (quarterly or monthly)
- Written experiment proposals with hypotheses
- Defined blast radius and abort criteria
- Some automated tooling (but mostly manual execution)
- Dedicated SRE time allocated for chaos experiments
- Results documented but not always acted upon

Key practices at this level:
- Experiment proposal template (included in this toolkit)
- Game day planning process
- Post-experiment reporting
- Basic steady-state hypothesis checking

How to progress: Automate experiment execution and integrate chaos testing into the CI/CD pipeline for at least one service.

Level 3: Automated (Systematic)

Characteristics:
- Experiments run automatically on a schedule
- Integration with CI/CD (chaos gate before production)
- Automated steady-state verification
- Progressive blast radius expansion
- Experiment catalog maintained and regularly updated
- Multiple teams participate and own their service's chaos tests
- Results tracked over time with regression detection

Key practices at this level:
- Automated experiment execution (Litmus, Gremlin, or custom tooling)
- Blast radius control with automatic abort
- Steady-state hypothesis as code
- Chaos experiment coverage metrics
- Integration with incident response (experiments inform runbooks)

How to progress: Extend chaos testing to production environments with continuous (not just scheduled) experimentation.

Level 4: Continuous (Production Chaos)

Included with Chaos Engineering Toolkit

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