Improve UX for enabling TCP keepalive for downstream connection

[andy-fong]

Gloo Edge Product

Open Source

Gloo Edge Version

1.17

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

envoy only supports enabling TCP keepalive on downstream connection through the generic socket_options on the Listener config. On upstream clusters, it has the tcpkeepalive structure but not for downstream.

gloo currently expose the socket_options setting to enable TCP keepalive (see example here. Having to set 4 socket options is tedious and can be error prone.

We can expose the TCP keepalive object for downstream and translate to the socket options envoy needs for better UX.

Describe the solution you'd like

In Gloo Mesh Enterprise, we have an implementation that exposes a ListenerConnectionPolicy resource that can be applied to the listner to setup TCP keepalive. See example here. We can have similar implementation to improve UX.

Describe alternatives you've considered

No response

Additional Context

No response