What happens if a healthcheck fails permanently?

If the DB's healthcheck reaches its maximum number of retries without succeeding, its status changes to 'Unhealthy'. Compose will see this, cancel the boot sequence, and the API container will NEVER be started. Compose will throw an error and exit.

Should I write retry logic in my application code instead?

YES! Even with `service_healthy`, it is considered a best practice for your application code to have retry logic (e.g., trying to connect to the DB 5 times before crashing). Networks are inherently flaky. A robust app handles transient failures itself.

Does `depends_on` restart the API if the DB crashes later?

No. `depends_on` is strictly a startup/teardown sequence manager. It does NOT monitor the containers while they are running. If the DB crashes an hour later, the API will throw connection errors unless you have Swarm or Kubernetes managing the active lifecycle.

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Service Orchestration

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