First off, you need the newest release of the CLI install package from VMware, which can be freely downloaded here.
Having installed, I highly recommend a restart of the workstation you using the CLI on. On my system, some of the Perl related libraries the CLI depends on didn’t seem to work till I did a restart.
Having restarted, bring up a Windows command line prompt, ideally in elevated admin mode (to make sure you have unrestricted access to your own system). Normal mode should be ok, as long as your update files have been downloaded to a local file system that can be accessed by your user account.
You also need to have the VMware vSphere Client installed, which you should be able to get (if you don’t have it already) just be entering the IP address of your ESXi host in a web browser window. The web server running on there should give you a download link.
Finally, go on the VMware website, and download the latest patches you want to apply to your ESXi 5 setup. At this present moment in time, I was applying the major Nov 2011 update, which brought me up to ESXi 5.0.0 build 515841.
For simplicity, having downloaded the latest ‘vib’ update (VMware’s terminology for an update archive, normally in the form of a ZIP file), I renamed it to Update.zip.
Having done this, you will need to upload the file into one of your storage volumes via the vSphere client. Note the path location to where you put the file. Furthermore, make a note of the full storage mount location of the actual data store, which can be found by selecting the datastore under Configuration -> Storage in vSphere client, and looking in the bottom panel labelled Datastore Details. As much as a pain it might be, my findings were that it was easiest to take the whole entry next to ‘Location’ and not substituting the common name of the datastore (so the entry you need will have a long GUID type path entry).
Go back to the Windows command line and type one of the following from the command prompt in order to get in to the CLI script folder:
For 32-bit OS:
cd C:\Program Files\VMware\VMware vSphere CLI\bin
For 64-bit OS:
cd C:\Program Files (x86)\VMware\VMware vSphere CLI\bin
You may also wish to enter your host in to maintenance mode before doing the update, which can be easily done from the vSphere Client.
Finally type the following command:
esxcli -s 192.168.0.10 -u root -p password software vib install -d
In the above, I’ve put my personal entries in unboldened italics. You will need to put in your own entries as follows:
-s Your Server IP or Hostname
-u Your ESXi host admin user name, normally ‘root’
-p Your ESXi host password
-d The location of your Update.zip file, using the location of the datastore, and the further folder location you may have created to put the update in (the ‘d’ stands for ‘depot’, by the way).
When you hit enter, the cursor will drop for a time, and nothing may appear to happen for several minutes. If the update is successful, you will eventually get an installation result message confirming all is ok, with a list of all updates applied. If it fails, I assume it will tell you, but it has yet to fail for me :)
You will then need to go back in to the vSphere client, restart the ESXi server, and then take it out of maintenance mode. Then manually fire up any virtual machines you have. You should then be done.
There may be a way of applying multiple updates simulteneously, but I’ve yet to need to do that. Doing one file at a time should work ok though (I suggest oldest updates first).