We have deployed Network Load Balancer target to nginx webserver using PHP-FPM.
We are receiving various reset count shown in below image. Could any one help understanding these counts?
These are TCP RST packet counts. For a TCP connection to remain alive, either party should exchange some data before idle timeout. On a UNIX OS (server/target), idle timeout is governed either by tcp_keepalive_time
or tcp_keepidle
parameter. On the client it depends upon how it's implemented or it may use the same parameters if it's also a UNIX OS. If either of the parties fail to send any data, the connection is closed after which if a client or a server send anything they'll receive a TCP packet with RST bit set and they'll know that the connection is no longer valid.
Client Reset Count: The total number of reset (RST) packets sent from a client to a target
Target Reset Count: The total number of reset (RST) packets sent from a target to a client
Load balancer Reset Count: The total number of reset (RST) packets generated by the load balancer
. It usually happens in cases where any target has started to fail or is being marked unhealthy or for a connection request to a target which is already marked unhealthy.