Planned lessonJNR-052-L04

Health checks: liveness vs readiness

On This Lesson 4 topics

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

expose and use the two health signals.

Liveness asks: "is the process stuck and in need of a restart?"
Readiness asks: "can the app take traffic now?" (for example, the database is reachable).
Spring Boot Actuator exposes /actuator/health/liveness and /actuator/health/readiness (enable the probes; verify properties for your version).
Do not check the database in liveness: a database outage would restart healthy apps and make things worse.
Expose only the health endpoint publicly; keep other actuator endpoints private.

Draft outline details

yaml

management:
  endpoint.health.probes.enabled: true
  endpoints.web.exposure.include: health

Which probe should fail when the database is down?

Show answer

Readiness.

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