VCP5 - Identify steps required to upgrade a vSphere implementation

Upgrading is generally a top-down process starting with the Virtual Center Server, then hosts, then VMs. This ensures that everything is properly supported during the upgrade process.

1. Make sure vSphere plug-ins are supported in vSphere 5
1. Upgrade or remove them if necessary
2. Confirm the environment meets the system requirements
3. Upgrade vCenter Server
4. Upgrade VMware Update Manager
5. Upgrade ESXi hosts
6. Reconfigure Licensing
7. Upgrade VMs

Note that this process will differ somewhat if using VMware View.

http://pubs.vmware.com/vsphere-50/index.jsp?topic=/com.vmware.vsphere.vcenterhost.doc_50/GUID-E1D90120-73EB-4B00-9F89-8650EBE911F7.html