Question : What are our options to upgrade our Master-Local setup from Aruba OS 6.1.3 to 6.3 when ?upgrading all Controllers at the same time is not feasible?
Environment Information : Any Mobility Controller, Aruba OS 6.1.3.x
Symptoms : Multi-Controller environment needs proper planning before upgrade to ensure minimal downtime and smooth operations.
Cause : It's highly recommended to have Master and Local Controllers on the same code, else it causes issues with configuration sync up and can cause delayed AP failover times between Controllers on different codes.
Resolution : The best recommendation is as per the release notes that is to upgrade all the Controllers simultaneously and to disconnect the Master-Local connectivity meanwhile. We could implement this with minimal downtime by copying the new Aruba OS to backup partition of all Controllers, schedule a downtime and reload all Controllers during the downtime.
If the local Controllers cannot all be upgraded at the same time, we could convert the locals to individual masters and upgrade each Controller when possible.
Answer :
It is best to try and upgrade all Controllers simultaneously. If we are unable to upgrade/reload all local Controllers in one downtime or need to test one of the Controllers on 6.3 before upgrading the rest, we could choose one of the following options:
1) Convert Locals as individual Masters and upgrade the locals individually. Note that we should refrain from making any changes to the WLAN configuration on the Master Controller.
2) Another option is to upgrade Master Controller to 6.3 first and test an AP on the Master and then upgrade Locals gradually. This option is not ideal by design because the configuration sync between Master and Locals will be partial while they are on different code branches. This should be a temporary or transitionary phase and subsequently the locals should all be upgraded to 6.3 to sync up the configuration with the master and allow smooth AP failover as needed.