Here's a summary of the environment I was working with (original configuration blog is found here):
- 2 vCenter Servers in 2 different geographical locations
- each vCenter Server has it's own instance of SSO in a multisite configuration
- all the components of vCenter Server are installed on one server
- linked mode is configured
As with any upgrade process, take backups before you start. In this case here, it is important to snapshot/backup both vCenter servers as they have dependencies with each other.
While there are probably many different ways to upgrade the vSphere environment, this method was what worked for me. The overall steps can be summarized as:
- Break vCenter Linked Mode
- Clean up Application Users registered with SSO
- Upgrade SSO
- Upgrade Web Client
- Upgrade Inventory Services
- Upgrade vCenter Server
- Upgrade Update Manager
- Upgrade Second vCenter Server
- Rejoin vCenter Linked Mode
1. Break vCenter Linked Mode
Log in to one of the vCenters and open up the Linked Mode configuration installer.
Proceed through the installer and isolate the vCenter Server from the linked mode group (essentially destroying the linked mode group if you only have 2 vCenter Servers).
If you have more than 2 vCenters, I assume you will have to repeat this for all the vCenter Servers.
2. Clean up Application Group users in SSO
Connect to the web client and login using any account that has access to make SSO configuration changes. I used the default admin@system-domain account which was created in the default 5.1 installer.
Once logged in, navigate to the SSO Users and Groups > Application Users section.
Remove any Application Users entries that are not associated with this vCenter. If you are unsure which ones belong to this vCenter, you can always make a clone of the vCenter and uninstall components to see which ones get removed.
3. Upgrade SSO
At this point, you'll want to stop all the VMware related services. One additional task that you may want to do is to change the autogrowth options for the vCenter log database as explained here.
Once that is done, launch the vSphere 5.5 Installer and select Custom Install > vCenter Single Sign On to upgrade SSO.
Proceed through the setup, selecting the defaults. You may get a warning regarding not being able to contact the SSO services in order to confirm the certificates. Accept the default to continue past that.
Select first existing "vCenter Single-Sign On server".
Set the default firstname.lastname@example.org password. Make sure to note this down for future references.
4. Upgrade Web Client
Launch the custom install for the Web Client and proceed through the set up. Everything should be default and self explanatory.
5. Upgrade Inventory Services
Similar to the upgrade procedure for the web client, launch the custom installer for Inventory Services and proceed with the installation selecting all the defaults.
6. Upgrade vCenter Server
Next, upgrade vCenter Server. Run the custom installer and proceed with the installation.
Upgrade the existing vCenter Server database.
Upgrade all the hosts automatically.
I chose to use the Windows Local System account, you may want to put in your service account credentials. Proceed with the remainder of the setup choosing the defaults.
7. Upgrade Update Manager
Launch the installer for the update manager and proceed with the installation selecting all the defaults.
Enter the credentials for your VUM database.
Restart the vCenter Server and then proceed to the next step of upgrading the second (or more) vCenter Servers.
8. Upgrade second vCenter Server
Once the first vCenter Server has been restarted, repeat steps 2-7 for the secondary vCenter Server. During the installation of SSO, select "An additional existing vCenter Single-Sign On Server in a new site". Enter the required information, pointing it to the first vCenter.
9. Rejoin vCenter Linked Mode
Once the second vCenter Server has been upgraded and restarted, run the Linked Mode Configuration installer and join the vCenters together.
This concludes the vCenter Server 5.1 to 5.5 upgrade.