The most important part first: Do have a failback plan if the installation does not succeed.
- Do a backup of your vCenter DB before attempting to upgrade.
- If certs are involved be extra careful.
- Note down all your permissions you have set.
- Check compatibility with all installed plugins for 5.1
- Do not use any non ASCII characters for passwords, usernames, hostname etc.
After the installation of SSO I would recommend that you open an elevated shell and do the following:# cd cC:\Program Files\VMware\Infrastructure\SSOServer\utils# ssocli manage-identity-sources -a list -u adminIf domain users have permission on your vCenter server all the domains should be listed as an output, if they are not do not continue the installation# ssocli manage-identity-sources -a create -u adminThis let's you add an identity source, for ease of use the Web Client can also be installed before installing the Inventory Service and upgrade vCenter Server to add the domains. If you omit this step permission loss will happen.SSO does not understand domain trusts. vCenter 4.x would allow a user that is defined in domain B and joined to a group in domain A to connect to vCenter server when the group does have the correct permissions. Both domains need to be defined in the SSO for that scenario to still work in vCenter server 5.1.
- Install the Inventory Service
- Upgrade vCenter server
- Install the Web Client
- Upgrade the vSphere client
- Upgrade Update Manager
All the new features are only available in the Web Client, as is the GUI for SSO configuration.
Hope this helps you to have a smooth upgrade without any issues.
Regards
Girish