Adaptation
Adaptation is the architectural principle of adjusting systems at runtime to changed conditions to maintain availability and performance.
Classification
- ComplexityMedium
- Impact areaTechnical
- Decision typeArchitectural
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Oscillation due to insufficient damping or too aggressive rules.
- Hidden side effects when changing topology or configuration.
- Lack of transparency hampers root-cause analysis.
- Introduce gradually with canary phases and rollback mechanisms.
- Careful tuning of hysteresis and damping to avoid oscillations.
- Comprehensive logging and auditability of automated actions.
I/O & resources
- Runtime metrics (CPU, latency, errors)
- SLO/SLA targets
- Configuration and policy definitions
- Configuration changes or scaling actions
- Alerts and audit logs
- Metric changes to evaluate effect
Description
Adaptation describes the capability of systems and architectures to dynamically adjust behavior, configuration, or topology in response to internal state changes or external environmental conditions. The goal is to preserve robustness, availability and performance. It includes design principles, runtime control, observability and feedback loops for decision making.
✔Benefits
- Increased availability through automatic reaction to failures.
- Better resource utilization through dynamic adjustment.
- Faster response to changing load and environmental conditions.
✖Limitations
- Increased implementation and operational effort.
- Potential instability with poorly calibrated rules.
- Not all problems are suitable for automatic runtime adaptation.
Trade-offs
Metrics
- Mean Time To Recover (MTTR)
Time to recover a failing service after an automated adaptation.
- Adaptation frequency
Number of adaptations per time unit as an indicator of responsiveness.
- Stability rate
Share of adaptations that cause no negative effects within a defined stabilization period.
Examples & implementations
Autonomic Computing concepts at IBM
IBM developed autonomic computing as a framework for self-managing systems with monitoring and reaction mechanisms.
Autoscaling in Kubernetes
Kubernetes Horizontal Pod Autoscaler adjusts replicas at runtime based on defined metrics.
Feature-flag based rollbacks
Feature flags enable fast, controlled behavior adjustment without deployments.
Implementation steps
Identify metrics and set up observability pipeline.
Define adaptation goals and thresholds, including stabilization times.
Implement, test and roll out automation rules incrementally.
⚠️ Technical debt & bottlenecks
Technical debt
- Ad-hoc rules without centralization hinder maintenance.
- Insufficient documentation of adaptation logic.
- Lack of automated tests for adaptive scenarios.
Known bottlenecks
Misuse examples
- Scaling solely due to a short-lived metric spike without smoothing.
- Automatically disabling critical functions without fallback.
- Using adaptive rules to cut costs at the expense of availability.
Typical traps
- Underestimating observability costs for fine-grained rules.
- Missing test coverage for adaptive paths.
- Blurring responsibilities between automation and ops teams.
Required skills
Architectural drivers
Constraints
- • Limited measurability of business metrics in real time.
- • Regulatory requirements may forbid certain automatic adjustments.
- • Incompatible configuration models between components.