A few days ago someone dropped a comment on one of my blog posts asking how they could Enter an ESXi host into maintenance without migrating VMs off of it automatically using PowerCLI. The -Evacuate switch for the cmdlet in question (Set-VMHost) didn’t see to be working when assigning the value of $false and hence they were unable to put hosts into maintenance mode without evacuating VMs first with PowerCLI.
Perhaps the cmdlet was being used incorrectly, or there is a better way of doing this, but that is not the point of this post. The point of this post is to show you the power and usefulness of Project “Onyx”. Project “Onyx” is an application released (quite some time ago!) by VMware that is essentially a “script recorder”. It connects to your vCenter instance, and in turn, you connect to it as a proxy using your vSphere client. Communications are not secured when doing this, so everything you do in your vSphere client is able to be recorded. You essentially end up with a “recording” of API calls that can be utilised in PowerCLI. Where this comes in handy is where you are not able to achieve something with PowerCLI’s already huge library of cmdlets. In this case the -evacuate switch of Set-VMHost was not working the way I expected it to work, and so to avoid wasting time trying to figure out what I needed to do, I just fired up Project Onyx, connected to it via the vSphere Client, then told an ESXi host to enter maintenance mode (unticking the migrate powered off / suspended VMs option of course) whilst the Project Onyx application was set to “record” mode.
The console then collected the necessary script, and I just modified it as necessary to create a small script that did the exact same task, but this time in PowerCLI.
To use Project “Onyx” simply download it from this page, then run the executable once you have extracted the .zip file. Tell Onyx to connect to your vCenter Server, then use your vSphere Client to connect to the machine that Onyx is running on (IP). Make sure you specify the correct listening port in the vSphere Client connection too – it will be the port listed in the Window Title bar of the actual Project “Onyx” application when it is running. Click the record button in the Application and then perform the required tasks using the vSphere Client.
