Bug: Instance reported as down even if it's up

[cdprete]

Spring Boot Admin Server information

• Version: 3.5.2

• Spring Boot version: 3.5.5

• Configured Security: None

• Webflux or Servlet application: WebFlux

Client information

• Spring Boot versions: 3.5.3

• Used discovery mechanism: Eureka

• Webflux or Servlet application: Servlet

Description

Hello.
I've the weird behaviour that an application is reported as DOWN in SBA even if its health endpoint reports it as UP.

Moreover, I can see in the HTTP Exchanges view that the health has been indeed called and that it returned 200, but somehow it's not reflected in the status of the application.

[cdprete]

Hello.
Today I observed the same behaviour in our production instance with version 3.5.5:

What I observed is that in the journal the latest STATUS_CHANGED event is about the application migrating from UP to DOWN, which is potentially fine, but then a next STATUS_CHANGED event is basically missing there which would put the app from DOWN to UP:

This would explain to me why the app is then reported as DOWN, but that's then very bad, especially if the health reports the system as UP then.

[cdprete]

Indeed, the /applications call triggered while loading the homepage is returning the latest available status for all the registered applications, which explains why the issue - UI wise - occurs.
This doesn't explain why the backend is failing somehow, of course.

[cdprete]

If retries would be implemented in #4516, these would probably be beneficial for this as well. (maybe even solve it)

[cdprete]

Hello.

I can confirm the issue with version 3.5.6 as well.
The homepage was reporting an instance as UP but its health status was reporting it as AT WORK (a custom status we've) and the latter was not correctly reflected in the homepage view which was reporting the status of such instance as UP.
Checking the journal entries for the instance, a UP -> AT WORK status update entry was clearly missing, explaining why it was not reported correctly.

@SteKoe @erikpetzold @ulischulte I don't know if #4784 may help with this.