Bulkheads prevent failures from spreading:
Ship analogy: Ships have watertight compartments. One breach doesn't sink the ship.
In software: Isolate resources per service or feature. Separate thread pools, connection pools, or even separate instances.
Example: Your payment service has its own database connection pool. If the recommendation service overloads its pool, payments still work.
Implementation:
- Separate thread pools per dependency
- Resource limits per tenant
- Dedicated clusters for critical paths