A: Multiple options exist for upgrading a VMware vSphere environment from version 4.1 to 5.0, with many of these options being highly automated in nature. Consider the following five methods as general guidelines, each with an increasing level of automation:

  • Upgrade hosts interactively, one at a time, from media
  • Upgrade hosts via unattended installations
  • Upgrade hosts via esxcli commands
  • Use vSphere Update Manager to perform an orchestrated upgrade
  • Upgrade via implementing vSphere Auto Deploy

Of these, using the vSphere Update Manager provides an excellent balance of effort and reward in completing an upgrade. It's possible with vSphere Update Manager to remediate ESXi hosts to the new version using a process very similar to applying patches. For environments desiring even greater automation and flexibility, consider exploring the new vSphere Auto Deploy functionality, which can fully eliminate the need for local hard disks.