The firmware on the first spine is downloaded.
Enabling maintenance mode on a
spine also involves the Border Gateway Protocol (BGP). The
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.
The
running-configuration is saved on the first 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 is disabled to allow traffic again through the upgraded spine.
The
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.
