Detailed VM Storage Information in vCloud Director

I recently had a request from one of our customers who wanted an easy / scriptable method to determine the storage allocations on their hosted VMs in our vCloud platform, preferably from PowerShell. That should be easy I thought and set about my usual Google-based research. I initially found this post from Alan Renouf which I forwarded back to the client.

Unfortunately, while this achieved part of the answer, this particular customer had a number of VMs which had hard disks attached using multiple/different storage profiles and they wanted to get the details of these too. So I set about writing some code to see if I could get full storage information about the VM and all of its disks. I ended up having to access the vCloud REST API directly for this information but it wasn’t too bad.

First, I created a ‘worst-case’ test VM where the 3 attached hard disks which were created one each on our ‘Gold’, ‘Silver’ and ‘Bronze’ storage policies:

test02-hardware-properties

(Just to make sure everything would work I also created the 3 disks on 3 different storage Bus Types). I also set the VM storage policy to something different:

test02-general-properties

My first step was a function to access the vCloud REST API, I found this post from Matt Vogt’s blog which had some code for this which I shamelessly borrowed (hey, why reinvent the wheel unless you need to):

The return from the Get-CIVM cmdlet includes a reference to the VM object within the vCloud API:

Using this we can obtain our disk information:

Filtering the returned RasdItemsList for a ResourceType of 17 (Hard Disk), we can get a list of attached hard disks:

So this gets us to a point where we have all of the hard disk information, but how do we find the storage policy for each disk? It turns out that each disk has an attribute ‘HostResource’ which provides the URI to the storage policy from which the disk has been allocated:

So how can we convert the storageProfileHref values into meaningful (human readable) storage profile names? We can use another API call to establish the name of each vdcStorageProfile:

Querying the API for every vdcStorageProfile for every disk is going to generate a lot of calls for any significant number of VMs, so in the code below I’ve added a hash stored in a global variable which caches these results so that any storageProfileHref which has been seen before doesn’t need to generate an additional API call.

Putting it all together

So we now have a way of determining all of the information we need, using PowerShell custom objects allows us to write a function which returns all of our VM and storage details in a easily consumable form for further processing.

The script included at the bottom of this article produces the following output for my test environment containing 2 VMs of which the ‘pxetest01’ VM has no disks attached:

It can also return just the disk information as another custom object:

And we can check the number of disks attached to any VM:

Finally because the output is a PowerShell object, we can easily turn this custom object into JSON for use in further processing:

Hopefully you’ve found this post useful, let me know in the comments if you have any issues or would like to see more examples like this.

Jon.

Full script to find storage policy information for vCloud VMs using the vCloud REST API:

 

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