To upgrade from ESXi 5.x or 6.x to the latest version using esxcli:
Shut down all VMs running on your ESXi host machine. Connect via SSH and run the following command to enter maintenance mode.
After putting ESXi into maintenance mode, run the following command to set the correct firewall rules for the httpClient:
esxcli network firewall ruleset set -e true -r httpClient
Next, run the following command to list the ESXi 6.x updates available. You want the latest one that ends in “-standard” for your version of VMware.
esxcli software sources profile list -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml | grep ESXi-6
Once you’ve identified the correct version of VMware (as of 4-18-2015, this is ESXi-6.0.0-20150404001-standard), run the following command to download and install the update.
esxcli software profile update -d https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml -p ESXi-6.0.0-20150404001-standard
It is very important that you run esxcli software profile update here. Running esxcli software profile install may overwrite drivers that your ESXi host needs.
Once the update has been installed and prompts you to reboot, run the following command to restart:
After your ESXi host restarts, connect via SSH and run the following command to exit maintenance mode:
At this point, your ESXi host should be upgraded to ESXi 6.x.