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Cloud
Behavioral
Singleton Service
Ensure only one instance of a service runs using PodDisruptionBudgets
Intent & Description
The Singleton Service pattern ensures that only one instance of a critical service runs at a time using PodDisruptionBudgets (PDBs). PDBs limit the number of pods that can be down simultaneously during voluntary disruptions, maintaining service availability. This is crucial for services that cannot tolerate concurrent instances.
Real-world Use Case
Use when you need to ensure only one instance of a service runs or when managing voluntary disruptions during maintenance.
Advantages
- Prevents concurrent instances
- Maintains availability during maintenance
- Integrates with cluster operations
- Supports graceful scaling decisions
Disadvantages
- May reduce availability during failures
- Requires careful capacity planning
- Does not prevent involuntary disruptions