Load Balancing on custom metric

[sysrun]

Is your feature request related to a problem? Please describe.

I want to use custom metrics like the cpu strategy

Additional context

I have multiple instances of one service. Every service can handle a limited amount of "slots". If no slot is available the load balancer should not try to send the request to the service which has no slots available.

[icebob]

What is the question or problem?

[sysrun]

I am not sure how to make a service aware of a "dynamic" value (like the cpu in the CpuStrategy) which i could use in a custom LB-Strategy.

Example:

i have 3 instances/nodes of 1 service. This service is exposing an action called "assign". The service also has a "assigncounter" which is incremented if a "service.assign" is called at the specific instance.

Now i want to Loadbalance - so i have to know which instance has the lowest "assigncounter".

So: How could a LB-Strategy access such dynamic service variables? :)

[icebob]

It can be only complicated way. The CPU strategy can work because CPU usage is shared between nodes, the INFO packet contains it. But a custom value is not shared and synchronized between the nodes. For this purpose, I recommend to use Redis to store and increment the value of your variable and get this value from the Redis in your Strategy.

[sysrun]

Ah, ok. Thanks :)

Redis is already my "plan b".

Would be nice if there would be an option to register custom stats in the future.