I have 5 k8s worker nodes that each of them run a kong instance. I also have 24 upstream servers. One month ago the number of my threads on the upstream servers increased dramatically, therefore, I was wondering about setting up keep alive in kong. I set the following variable for them:
KONG_UPSTREAM_KEEPALIVE_POOL_SIZE = 24
KONG_UPSTREAM_KEEPALIVE_MAX_REQUESTS = 100
KONG_UPSTREAM_KEEPALIVE_IDLE_TIMEOUT = 60
I set connection pool to 24 but I still have 200 thread opens on each of my upstream servers. why is that? is not it supposed to open one thread for each connection? or does it open a thread for each of requests? what is the maximum TPS that I can obtain from the mentioned variables?