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Retrieving detailed per-VM space utilization on VSAN

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I was recently helping out my friend Paudie O'Riordan with a request from a customer who was looking for a way to collect detailed space utilization for their VMs (VM Home, VMDK & swap) running on VSAN. Today, this level of granularity is not available in the vSphere UI and the customer was interested in both the used and reserved capacity on a per-VM basis. Luckily, this information can be retrieved using the VSAN Management API.

To do so, we just need to use the VsanQueryObjectIdentities() API method, which I have used in the past to retrieve things like "thick" provisioned VM and translating VSAN Object IDs to their friendly VM display name. To retrieve space utilization information, we just need to set the includeSpaceSummary property to be true. While developing the PowerCLI sample script, I found that this specific property is currently not supported when querying vCenter Server and to retrieve this information, you must go directly to each ESXi host within the VSAN Cluster. I have already filed a feature request and it looks like this will be fixed in a future vSphere release.

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Leveraging Instant Clone in vSphere 6.7 for extremely fast Nested ESXi provisioning

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The idea of "Instant Cloning" a Nested ESXi VM (running ESXi in a VM) is not a new concept. In fact, I had shared a solution back in 2015 using the private VMFork APIs. However, what has changed is the ease of consumption, primarily due to the re-architecture of Instant Clone in vSphere 6.7 (more details here and here) which resulted in a public and simplified API. Some of you might ask, why not simply clone a Nested ESXi VM or create a Link Clone? What benefit would I get by using Instant Clone?

The answer is not only speed, but the fact that the instantiated VM is fully operational and ready to start executing where as a traditional full clone or linked clone requires a full OS boot up that can take up to several minutes to deploy and configure. This may not sound like much for a small number of Nested ESXi VMs, but as you increase the number of instances, Instant Clone really shines while still maintaining speed and the instant availability of the VM. As you can imagine, this definitely opens up for some interesting use cases whether it be for personal home lab or educational purposes like VMware HOL. In addition, we also have customers who deploy Nested ESXi not only at high scale but also with a high churn rate for development purposes, think CI/CD type of a workload who can also benefit from Instant Clone.

So how fast are we talking about? Lets say you wanted to test out the latest version of VSAN in vSphere 6.7, you would normally deploy 3 Nested ESXi VMs, power them up and wait for them to be ready on the network. With Instant Clone, you can deploy three fully functional Nested ESXi VMs in just 30seconds! As the VMs are instantly available for consumption, you can start the VSAN enablement workflow immediately and even parts of that can be baked into the Instant Clone workflow. With the ease of provisioning Nested ESXi VMs, you can simply maintain a catalog of ESXi templates which are in "frozen" states and then leverage Instant Clone to deploy just-in-time Nested ESXi environments and discard them once you are done. Pretty slick if you ask me! and something I plan on using going forward.

Disclaimer: Nested ESXi is still not officially supported by VMware. Please use at your own risk.

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How to check when the VSAN Hardware Compatibility List (HCL) is updated?

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While catching up on emails from being out on paternity leave, I came across a VSAN HCL feature request that I had filed in early December of last year. I was pleasantly surprise to see that it had been marked resolved. The VSAN Hardware Compatibility List is continuously being updated to include new hardware platforms and components that have been certified by our hardware vendors.

This of course is great news for our customers, but one challenge that I have heard on several occasion is how to keep up with the changes, especially the addition of new components? The VSAN HCL allows you to subscribe and get notification on individual components which is useful to get the latest recommendation. However, in the case of new components being add or even removed, there is no easy solution and most folks resort to manually checking the VSAN HCL by hand.

VSAN itself does include an HCL healthcheck, which you can have it directly pull the latest VSAN HCL JSON from VMware's website, although this may not always be possible for customers without direct or proxy access to the internet. This means for customers who may have dark sites, they must periodically download the latest VSAN HCL JSON and distribute that throughout their vCenter Server, where as a more ideal solution is to only push the update when a new JSON has been provided by VMware.

My feature request was quite simple, it asks for a method in which customers can easily subscribe and get notified of when the VSAN HCL database has been updated. This has been delivered as a tiny RSS feed service.

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