VMware provides several ways to upgrade ESX/ESXi hosts:
You can upgrade an ESXi 5.0.x, ESXi 5.1.x, or ESXi 5.5.х host directly to 6.0. For more details, see the
Supported Upgrades to ESXi 6.0 section in the
vSphere Upgrade Guide.
vSphere Update Manager
vSphere Update Manager is a software for upgrading, migrating, updating, and patching clustered hosts, virtual machines, and guest operating systems. Update Manager orchestrates host and virtual machine upgrades. If your site uses vCenter Server, VMware recommends that you use Update Manager.
Using vSphere Update Manger, you can perform an orchestrated upgrade. Orchestrated upgrades allow you to upgrade the objects in your vSphere inventory in a two-step process: host upgrades, followed by virtual machine upgrades. For more information, see the
Using vSphere Update Manager to Perform Orchestrated Host Upgrades section in the
Orchestrated Upgrades of Hosts and Virtual Machines
Upgrade or migrate interactively using an ESXi installer ISO image on CD/DVD or USB flash drive
You can run the ESXi 6.0 installer from a CD/DVD or USB flash drive to do an interactive upgrade or migration. This method is appropriate for deployments with a small number of hosts. The installer works the same way for a fresh installation, but if you select a target disk that already contains an ESXi 5.x installation, the installer upgrades the host to ESXi 6.0 and gives you the option to migrate some existing host settings and configuration files and preserve the existing VMFS datastore.
Scripted upgrade
You can upgrade or migrate ESXi 5.x hosts to ESXi 6.0 by invoking an update script for an unattended upgrade. Scripted upgrades provide an efficient way to deploy multiple hosts. You can use a script to upgrade ESXi from a CD, DVD, or USB flash drive, or by PXE-booting the installer. You can also call a script from an interactive installation.
vSphere Auto Deploy
If you have hosts deployed using vSphere Auto Deploy, Auto Deploy can be used to reprovision the hosts with a new ESXi 6.0 image profile. Use the ESXi Image Builder PowerCLI to create and manage image profiles as required. For more information, see the
Using vSphere ESXi Image Builder section in the
Using vSphere Auto Deploy to Reprovision HostsNote: After the host is deployed using an ESXi 6.0 image, it is deployed with certificates that are signed by the VMCA. If you are using custom certificates, you can set up the host to use the custom certificates again after the upgrade.
ESXi Command-line interface - esxcli
Using the vSphere Command Line Interface (CLI), you can upgrade ESXi 5.x hosts to version 6.0.
Note: The esxupdate and vihostupdate command-line utilities are not supported methods to upgrade to ESXi 6.0.