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Reporting vSAN Object distribution across vSAN Disk Groups using PowerCLI

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Several weeks back, I was cleaning up my scratch space, where I store all my random code snippets for various questions which I receive on a regular basis and I came across a nifty little script that I had put together for a particular customer request. I had completely forgotten about it and I thought it could come in handy for some folks who might be curious in how their current vSAN Objects are currently being distributed across all vSAN Disk Groups within a vSAN Cluster.

RVC already provides a nice command called vsan.check_limits which gives you a break down of the number of components across all disks within a vSAN Cluster as shown in the screenshot below.


However, in the case of this particular customer, they wanted the break down on a per Disk Group level rather than individual disks.

Luckily, all of this information is already exposed using the vSAN Management APIs, you simply just need to aggregate it one level up. With that, I created a PowerCLI script called VSANObjectDistribution.ps1 which allows you to provide the name of a vSAN Cluster and it will automatically provide you with both the number of components distributed across the different vSAN Disk Groups as well as the amount of storage consumed by these components.

Here is a screenshot for a 3-Node vSAN Cluster where each ESXi host contains two vSAN Disk Groups:


Since there is no actual number for a vSAN Disk Group, by default, I output the Canonical Disk Name of the "Cache" device for the given vSAN Disk Group so you can map it back.

If you prefer to see the vSAN UUID for the "Cache" device instead, you can simply set the -ShowvSANID parameter to true as shown in the screenshot below.


To correlate back the specific vSAN Disk Group, you simply select a particular vSAN Disk Group for the ESXi host you are interested in. At the bottom, add "vSAN UUID" column highlighted in orange and you can then compare either that ID or Canonical Disk Name highlighted in blue.

PowerCLI script to help correlate vCenter, ESXi & vSAN build/versions w/o manual VMware KB lookup

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I can still remember when I was a VI Admin and how annoying it was to try to correlate the build numbers for my ESX(i) hosts and vCenter Servers that I have deployed with the versions listed on VMware's website. This especially gets challenging when there are multiple patch releases (a, b, c or 01, 02, 03) in between major releases (5.5, 6.0, 6.0u1, 6.0u2, 6.5, etc.). Historically, most customers including myself would retrieve the respective build numbers and then manually comparing them to either the release notes and/or download website which was very tedious.

Although VMware has exposed the version number within our vSphere products since day 1 which can also be retrieved programmatically using the vSphere API (here), it unfortunately does not provide more details than simply the major/minor version (e.g. 5,5, 6.0, 6.5, etc) of the software. Recently, VMware had released a series of VMware KBs which provides a mapping between the build numbers for vCenter Server, ESXi and vSAN to their respective versions which can be found in the links below:

These are definitely a great set of resources that I know many customers including myself have been using since its release. Having said that, the process today is still pretty manual since you need to manually retrieve the build numbers for either a VC, ESXi or vSAN Host (can be automated using vSphere APIs) and then comparing that to the KBs to get the correct versions. How cool would it be if you could *easily* just point to YOUR environment and retrieve the version information for either a vCenter Server (Windows or VCSA), ESXi host(s) or vSAN host(s) without needing to manually perform this lookup each time? Well, I have just done that! I have taken all three KBs and converted that information into a simple PowerCLI script called VCESXivSANBuildVersion.ps1 leveraging our vSphere API and it provides three functions:

  • Get-VCVersion - Retrieves the vCenter Server version given a VC connection
  • Get-ESXiVersion - Retrieves the ESXi version for all hosts given a vSphere Cluster
  • Get-VSANVersion - Retrieves the vSAN version for all hosts given a vSAN Cluster

Here is an example output using the first two functions:


For the vCenter Server version output, you will notice that I am also including the OS platform of your vCenter Server, so you can distinguish between a Windows vCenter Server and a vCenter Server Appliance (VCSA) which can be useful to see if you have been #migrate2vcsa ;). For the ESXi version output, you will notice the "OriginalInstallDate" value, this is actually new API property that was introduced in vSphere 6.5 and it provides you with the original installation date of your ESXi host (more details can be found here) which is pretty neat.

Here is an example output using last function:


If you wanted to take this a step further, you could even take this output and dynamically update the vSphere UI using either Custom Attributes or vSphere Tags so you know what version the software is at any given moment. Its easy enough to set this up as a scheduled task that could run periodically so you always have the latest information provided in the vSphere UIs.

Although this is a significant improvement over the existing manual methods, I think most of you will agree that it would be ideal if this information was natively available within the product which means BOTH UI and APIs. I think we all appreciate versioning of software is not always easy and it can change from release to release for a variety of reasons, most of which may not be technical. If the vSphere platform could dynamically pull this information in either real time and/or through an offline mechanism and provide this association by default, it would greatly improve the experience when needing to troubleshoot or perform maintenance of the vSphere platform. If this is something you would like to see, please leave a comment below providing your feedback. I know I have already pinged our PMs about this and I am sure they would love to hear form you as well!

Additional Information:

Note1: Update levels can be found using the vSphere API, take a look at this article here for more details.

Note2: As of ESXi 6.5 Update 1, the Update levels are also included by default in the Embedded Host Client as shown in the screenshot below:

Note3: As of vSAN 6.2, the vSAN Management API already includes vSAN version information that can be queried. Take a look at this script here which exercises this new API. For example above, I decided to not use this new API since customers may be running older releases of vSAN which is not covered by the vSAN Mgmt API.

Note4: VMware has also published simliar build to version mapping for other VMware products which can find the complete list here.

How to convert vSAN RVC commands into PowerCLI and/or other vSphere SDKs?

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A common request that I see come up from our field and customers is getting specific vSAN Ruby vSphere Console (RVC) commands to be made more generally available in other vSphere CLI/SDKs like PowerCLI for example. Funny enough, many folks do not realize that this functionality has been there since vSAN 6.2 and specifically with the release of the vSAN Management APIs which exposes all vSAN functionality programmatically whether you are consuming it from the vSphere Web Client, Embedded Host Client or from RVC. All of these tools have been built using the vSAN Management APIs.

Although we have supported a variety of vSAN Management SDKs (language bindings) since its first release, I will say that PowerCLI consumption of the vSAN Management API has only been made available recently with PowerCLI 6.5.1 and it supports the latest release of vSAN 6.6 and can go all the way back to vSAN 6.2. Even with PowerCLI support, I still continue to see vSAN RVC requests come up time after time and it seems like folks still have not made the connection that RVC is just simply using the vSAN Management API just like UI does.

What is even more interesting is that the source code of RVC can be viewed by anyone to see how each command is implemented and which APIs are being used. RVC is built using rbvmomi (vSphere SDK for Ruby) which provides access to both the vSphere and vSAN Management APIs. Given the number of requests that I have seen, I am going to assume that this is not common knowledge and I figured the best way to show how this work is with a real world example. I decided to take the vsan.check_limits RVC command and create an equilvenet PowerCLI script that uses the vSAN Management API to provide the exact same information.

Note: You will need to know how to use the vSphere/vSAN Management APIs and knowing a little of Ruby can also help. If you are new to vSAN Management APIs, have a look at this blog post on how to get started.

Here is a screenshot of running the vsan.check_limits RVC command:


Here is a screenshot of running the PowerCLI script that I have created:


As you would expect, the data is exactly the same since they both consume the same underlying vSAN Management API.

So, how do we get started?

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