GoBGP's default value for deferral time is 360 seconds.
That means that the routes are not sent to the BGP peer until
this timer is elapsed, so a server is unreachable for 360
seconds, when kube-router restarts.

The new parameter is --bgp-graceful-restart-deferral-time duration_with_unit

For example '--bgp-graceful-restart-deferral-time 10s'