Create status endpoints for kubernetes

[mooreds]

Create status endpoints for kubernetes

Problem

Kubernetes needs different endpoints to manage FusionAuth correctly.

• liveness: is the application running
• readiness: is the application ready for traffic
• startup: is the application started (the other two don't get called if this returns false)

Solution

Add endpoints for these three application states. Make sure they are correct and return quickly. No other funny business.

Alternatives/workarounds

Use /api/status: https://fusionauth.io/docs/v1/tech/apis/system/#retrieve-system-status

However, this is a little heavyweight.

Additional context

Part of the ongoing kubernetes work.

Additional info about the endpoints: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/

How to vote

Please give us a thumbs up or thumbs down as a reaction to help us prioritize this feature. Feel free to comment if you have a particular need or comment on how this feature should work.

[robotdan]

Planning to add a new endpoint that is more purpose built for a k8s health check. /api/health.

This endpoint will not return a JSON body, and will only ever return 200 or 500.

It seems this one endpoint can account for all three states outlined above.

• startup - FusionAuth APIs will not respond until the application is running. If any API returns, app is started.
• liveness - return 200
• readiness - return 200

So this means that this won't be that much different from /api/status except that it will never return a JSON response, and the return codes are simplified to only have two states, and fewer health checks will run, so it should cost less to make this API call.

Internal:

• https://github.com/FusionAuth/fusionauth-app/pull/451