[FROG] how to trigger a graceful restart for a bgp session

[Xinyong Wang]

hi,

if we just did  `systemctl restart frr`, the bgpd process will be
stopped by `kill -2`, and it would send cease/peer de-config
notification to its peer. its peer will flush the routes insteading of
make them stale.

if we did `neighbor xxxxx shutdown`,then `no neighbor xxxxxx shutdown`
via vtysh, it would send   cease/administrative shutdown notification.
graceful restart did not work too.

Now, we have changed frrcommon.sh by  's/kill -2/kill -9/g', when bgpd
is killed by `kill -9`, it would not send any notifications, and this
time, graceful restart functionality works, its peer makes the routes
be stale and forwarding is perserverd during frr restarting. however,
we think this approach is ugly.

So can anyone tell us what is the corrent approach to restart bgp
session gracefully. we have to restart bgp session for upgrading to a
new version or changing some parameters, etc.

thanks!

best regards,
Xinyong