You might ask if/what the procedure is for updating Enhanced Linked Mode vCenter Server Instances, or is there even any considerations that apply?
vCenter Enhanced Link Mode is a feature that allows you to link a total of 15 vCenter Instances in to a single, Single Sign On (SSO) vSphere domain. This allows you to have a single set of credentials to manage all 15 instances, as well as the ability to manage all of them from a single pane of glass.
When it comes to environments with multiple vCenter instance and/or vCSA appliances, this really helps manageability, and visibility.
Enhanced Linked Mode Upgrade Considerations
To answer the question above: Yes, when you’re running Enhanced Linked Mode (ELM) to link multiple vCenter Server, special considerations and requirements exist when it comes to updating or upgrading your vCenter Server instances and vCSA appliances.
Not only have these procedures been documented in older VMware documentation, but I recently reviewed and confirmed the best practices with VMware GSS while on a support case.
Procedure for updating vCenter with ELM
- Configure/Confirm that the vCenter File-Based Backup in VAMI is configured, functioning, and that you are creating valid file based backups.
- Create a manual file-based backup with VAMI
- Power down all vCenter Instances and vCSA Appliances in your environment
- Perform a cold snapshot of all vCenter Instances and vCSA appliances
- *This is critical* – You need a valid offline snapshot taken of all appliances powered off at the same point in time
- Power on the vCenter/vCSA Virtual Machines (VMs)
- Perform the update or upgrade
Recovering from a failed Update
IMPORTANT: In the event that an update or upgrade fails, you must revert all vCenter Instances and/or vCSA appliances back to the previous snapshot!
You cannot selectively choose single or individual instances, as this may cause mismatches in data and configuration between the instances as they have databases that are not in sync, and are from different points in time.
Additionally, if you are in a situation where you’re considering or planning to restore previous snapshots to recover from a failed update, you should do so sooner than later. As time progresses, service accounts and identifiers update in the VMware vSphere infrastructure. Delaying the restore too long could cause this information to get out of sync with the ESXi hosts after performing a snapshot restore/revert.