All of the FIMs and FPMs in a FortiGate-7000F HA cluster run the same firmware image. You upgrade the firmware from the primary FIM in the primary FortiGate-7000F.
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 uninterruptible-upgrade enable
set session-pickup enable
When these settings are enabled, the primary FortiGate-7000F primary FIM uploads firmware to the secondary FortiGate-7000F primary FIM, which uploads the firmware to the secondary FIM and the FPMs in the secondary FortiGate-7000F. Then the FIMs and FPMs in the secondary FortiGate-7000F upgrade their firmware, reboot, and resynchronize.
Then all traffic fails over to the secondary FortiGate-7000F which becomes the new primary FortiGate-7000F. Then the FIMs and FPMs in the new secondary FortiGate-7000F upgrade their firmware and rejoin the cluster. Unless override is enabled, the new primary FortiGate-7000F continues to operate as the primary FortiGate-7000F.
Normally, you would want to enable
uninterruptible-upgrade to minimize traffic interruptions. But
uninterruptible-upgrade does not have to be enabled. In fact, if a traffic interruption is not going to cause any problems, you can disable
uninterruptible-upgrade so that the firmware upgrade process takes less time.
As well, some firmware upgrades may not support
uninterruptible-upgrade. Make sure to review the release notes before running a firmware upgrade to verify whether or not enabling
uninterruptible-upgrade is supported to upgrade to that version.