Appendix G: Upgrade Checklists : Phase 3
   
Phase 3
Upgrade Hosts
Backup host configurations.
Place host in maintenance mode, and confirm that vCloud Director detects that host is unavailable.
Perform upgrade to ESXi 5, removing any incompatible third-party packages that may be installed.
Reconnect upgraded host within vCenter to upgrade vCenter agents.
Disable maintenance mode.