Both management boards and all of the FPCs in a FortiGate-6000 HA cluster run the same firmware image. You upgrade the firmware from the GUI or CLI by logging into the primary FortiGate-6000 and installing the firmware image.
session-pickup are enabled, firmware upgrades should only cause a minimal traffic interruption. Use the following command to enable these settings (they should be enabled 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-6000 management board uploads firmware to the secondary FortiGate-6000 management board. The secondary management board uploads the firmware to all of the FPCs in the secondary FortiGate-6000. Then the management board and all of the FPCs in the secondary ForiGate-6000 upgrade their firmware, reboot, and resynchronize.
Then all traffic fails over to the secondary FortiGate-6000 which becomes the new primary FortiGate-6000. Then the management board and the FPCs in the new secondary FortiGate-6000 upgrade their firmware and rejoin the cluster. Unless override is enabled, the new primary FortiGate-6000 continues to operate as the primary FortiGate-6000.
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. For example,
uninterruptible-upgrade may not be supported if the firmware upgrade also includes a DP3 processor firmware 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.