graceful_shutdown
parameter is sent to all the spine‘s
underlay neighbors (all leafs in the pod and super-spines). The neighbors no
longer send traffic to the first spine going into maintenance mode and redirect
traffic to an alternate path.
running-configuration
is saved on the first spine to
preserve all current configurations including the maintenance mode enable
configuration.
running-config
is saved again to ensure the maintenance
mode config remains disabled.
The same process can be carried out on the second spine to upgrade the firmware without traffic loss.