Closing Strategy with Loadbalancer

[KniKnaKnorke]

Hi Florian,

I am upgrading one of our old jPro + load balancer systems. In the previous setup, we used the following parameters in application.properties:

-Djpro.keepAppAlivePercentage=0
-Djpro.keepAppAliveFor=28000

The newer jPro versions provides its own closingStrategy, which is a great way to define custom behavior. However, it does not seem to work when a load balancer is involved. When I run the app with jPro only, the closing strategy works as expected. But when I run it with both the load balancer and jPro, the instances are not being closed.

Should the closing strategy work together with a load balancer? If not, I would stop trying to get this working.

Im using jPro/load balancer version 2025.3.2.

Best regards,
Dennis
ableX GmbH

[FlorianKirmaier]

The config keepAppAlivePercentage and keepAppAliveFor are very old and no longer supported.

https://www.jpro.one/docs/jpro/docs/2/5/instance-close-strategies
The close instance strategy should work without problems in combination with the LoadBalancer.
If it really doesn't work, than we should take a look at it together.

Basically, the LoadBalancer just asks the JPro-Servers whether the Instance is still alive. The logic is entirely handled by the JPro Server.

[KniKnaKnorke]

Thanks for the fast response. I will retry it today and provide feedback.

With the old parameters, it was possible to define these settings without bundling them into the application. Is there any way to define such parameters like before, for example via application.properties or a similar external configuration?

[FlorianKirmaier]

all the values in the jpro.conf can be configured as parameters.

jpro {
  closeInstanceStrategy {
    short {
      until = 60
      closeOnTabCloseAfter = 0
      closeOnDisconnectAfter = 5
      closeOnAFKAfter = -1
      closeOnBackgroundAfter = -1
    }

==>

-Djpro.closeInstanceStrategy.short.until=60
-Djpro.closeInstanceStrategy.short.closeOnTabCloseAfter=0
-Djpro.closeInstanceStrategy.short.closeOnDisconnectAfter=5
-Djpro.closeInstanceStrategy.short.closeOnAFKAfter=-1
-Djpro.closeInstanceStrategy.short.closeOnBackgroundAfter=-1

A bit ugly, but should work.

[KniKnaKnorke]

I don’t know what I did wrong yesterday, but it works now. Thank you!