Created on
01-06-2023
06:32 AM
Edited on
10-15-2025
05:24 AM
By
Jean-Philippe_P
Description
This article describes how to fix HA (High Availability) cluster upgrade failure, which results in each firewall in the cluster having a different OS version.
Scope
FortiGate HA Active Passive.
Solution
Uninterruptible HA cluster upgrade mode (the default) will upgrade the secondary device before the primary.
In most failure cases with this option, the secondary device is successfully upgraded to a newer version while the primary device stays on the current OS version.
This problem can occur with any OS version and device model.
Pre-checklist:
The primary unit most likely has no newer image on its flash storage:
diagnose system flash list
Partition Image TotalSize(KB) Used(KB) Use% Active
1 FG100F-6.04-FW-build1914-211117 253920 102616 40% No
2 FG100F-7.00-FW-build0367-221005 253920 110112 43% Yes
3 ETDB-90.07704 3021708 790996 26% No
Image build at Oct 5 2022 22:02:56 for b0367
diagnose system ha dump-by kernel
<hatalk> HA information.
<hatalk> group_id=13, nvcluster=1, mode=2, load_balance=0, schedule=3, ldb_udp=0.
<hatalk> nvcluster=1, mode=2, ses_pickup=1, delay=0, load_balance=0
schedule=3, ldb_udp=0, upgrade_mode=0. <----- Upgrade_mode should be '0'. If not, reboot the firewall to reset this to 0.
Since each unit has a different OS version, the cluster status will be out-of-sync.
However, the session sync should still be running.
If all prerequisites are met, follow the steps below. Otherwise, contact Fortinet TAC for additional help.
If this step did not work and it is not possible to upload the image, follow step 2:
In this case, be sure that the secondary can take over the traffic in normal conditions.
Downgrade through the CLI with the following command:
execute set-next-reboot {primary | secondary} <-- Make sure the older image is there.
See this article: Technical Tip: Selecting an alternate firmware for the next reboot for more information.
If none of the steps above work, try the following:
Before starting an HA upgrade, validate that both units are running compatible firmware versions and that the cluster synchronization status is healthy.
If the upgrade fails, check HA logs, diagnose sys ha status, diagnose sys ha dump-by vcluster, and clear synchronization errors before retrying.
Note:
If the problem persists after following the steps above, contact Fortinet TAC for further assistance.
Related documents:
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