HA cluster firmware upgrades
All of the FIMs and FPMs in a FortiGate-7000 HA cluster run the same firmware image. You upgrade the firmware from the primary FIM in the primary FortiGate-7000 .
If uninterruptable-upgrade and session-pickup are enabled, firmware upgrades should only cause a minimal traffic interruption. Use the following command to enable these settings; they are disabled by default. These settings are synchronized.
config system ha
set uninterruptable-upgrade enable
set session-pickup enable
end
When these settings are enabled, the primary FortiGate-7000 primary FIM uploads firmware to the backup FortiGate-7000 primary FIM, which uploads the firmware to all of the modules in the backup FortiGate-7000. Then the modules in the backup FortiGate-7000 upgrade their firmware, reboot, and resynchronize.
Then all traffic fails over to the backup FortiGate-7000 which becomes the new primary FortiGate-7000. Then the modules in the new backup FortiGate-7000 upgrade their firmware and rejoin the cluster. Unless override is enabled, the new primary FortiGate-7000 continues to operate as the primary FortiGate-7000.
Normally, you would want to enable uninterruptable-upgrade to minimize traffic interruptions. But uninterruptable-upgrade does not have to be enabled. In fact, if a traffic interruption is not going to cause any problems, you can disable uninterruptable-upgrade so that the firmware upgrade process takes less time.
As well some firmware upgrades may not support uninterruptable-upgrade. For example, uninterruptable-upgrade may not be supported if the firmware upgrade also includes a DP2 processor firmware upgrade. Make sure to review the release notes before running a firmware upgrade to verify whether or not enabling uninterruptable-upgrade is supported to upgrade to that version.