The firmware on the first super-spine is downloaded.
Enabling maintenance mode on a
super-spine involves the Border Gateway Protocol (BGP). The
graceful_shutdown parameter is sent to all the
super-spine‘s underlay neighbors (all connected spines). Each neighbor processes
the graceful_shutdown and refreshes their routes to use the
alternate path. Maintenance mode is enabled on the first super-spine and traffic
is diverted to the second super-spine.
The
running-configuration is saved on the first super-spine to
preserve all current configurations including the maintenance mode enable
configuration.
The device is rebooted for firmware activation without traffic loss.
Once the new firmware is activated, maintenance mode can be disabled. The
graceful_shutdown parameter is removed from all the underlay
neighbors and traffic to the first super-spine is allowed again.
The
running-config is persisted again to ensure the maintenance
mode disabled state is retained.
The same process can be carried out on the second super-spine to upgrade the firmware without traffic loss.
