VSAN – Page 33

Exploring VSAN APIs Part 6 – Modifying Virtual Machine VM Storage Policy

03.20.2014 by William Lam // 6 Comments

One of the biggest benefit of VSAN is the ability to specify granular storage policies on a per Virtual Machine basis. These storage policies is managed through VMware's Storage Policy Based Management system and is automatically enforced by VSAN to ensure compliance. A VM Storage Policy can be assigned during the initial deployment of a Virtual Machine or it can be modified afterwards, for example if the Virtual Machine's SLA's has changed because the workload has changed. From the vSphere Web Client, modifying a Virtual Machine's VM Storage Policy is simply selecting the VM Storage Policy and re-applying which is also available programmatically through the vSphere API.

Using the vSphere API method ReconfigVM_Task(), you will be able to modify the VM Storage Policy for the VM Home Namespace and/or individual Virtual Disks. To modify the VM Home Namespace, there is a property defined at the root of the Virtual Machine config spec called vmProfile which accepts the VM Storage Policy ID extracted from the SPBM API. To modify the VM Storage Policy for an individual Virtual Disk, you will need to set the profile property which is exposed on a Virtual Device with the VM Storage Policy ID. To demonstrate this functionality, I have created a sample vSphere SDK for Perl script called changeVMStoragePolicy.pl

Disclaimer: These scripts are provided for informational and educational purposes only. It should be thoroughly tested before attempting to use in a production environment.

In my environment, I have a Virtual Machine called VM1 which has been defined with a VM Storage Policy called "Copper" as seen in screenshot below:

Let's say I want to change the Virtual Machine's VM Storage Policy to another policy called "Aluminum", I first need to extract the VM Policy ID from SPBM API and then pass it into the script like the following:

./changeVMStoragePolicy.pl --server vcenter55-1.primp-industries.com --username root --vmname VM1 --profileid cd6908b2-0704-4733-ad9b-a9a8f200ab0a

Once the Virtual Machine has been reconfigured, we can then take a look in our vSphere Web Client and we can see the VM Storage Policy has now been changed and VSAN will automatically enforce these new requirements.

If you wish to assign a VM Storage Policy as part of a new Virtual Machine creation, you just need to set the vmProfile and profile properties which is similar to a reconfiguration operation.

Re: Host is in a VSAN enabled cluster but does not have VSAN service enabled

03.18.2014 by William Lam // Leave a Comment

I recently noticed a couple of people hitting a warning message when configuring VSAN and specifically when running VSAN in a Nested ESXi environment (which is not officially supported by VMware). The warning message is displayed on the summary page of the ESXi host which states the following:

Host is in a VSAN enabled cluster but does not have VSAN service enabled

The reason you are seeing this issue is related to the amount of memory you have allocated for your Nested ESXi VM. During the VSAN Beta, the minimal amount of memory was 4GB but it looks like that has changed to 5GB with the GA of vSphere 5.5 Update 1 last week. I know we could have done better job with the error message and communicate the actual underlying issue (will ensure we have an FR filed for this).

However, the fix is quite simple, just shutdown your Nested ESXi VM and then change it to 5GB and this message will go away. It is also worth noting that as you increase the number of disks and disk groups in your ESXi hosts, there will be an increase in memory. I would highly recommend you take a look at the official VSAN Design & Sizing guide to properly size out your real VSAN environments.

For basic functional testing and education of VSAN (not including running additional VMs), running a Nested ESXi VM with 5GB will be sufficient. You can also take a look at the my VSAN Nested ESXi OVF template which can just download and install ESXi 5.5 Update 1 without any issues.

Exploring VSAN APIs Part 5 – VSAN Host Status

03.17.2014 by William Lam // 1 Comment

Another useful bit of information from a troubleshooting perspective is to be able to quickly get summary of all your ESXi hosts participating in a VSAN cluster. Critical information such as the health, state, VSAN Node/Cluster UUID for each ESXi host can be queried through the vsanSystem using the QueryHostStatus() vSphere API method. To demonstrate this simple operation, I have created a vSphere SDK for Perl sample script called vsanHostDiskMapping.pl.

Disclaimer: These scripts are provided for informational and educational purposes only. It should be thoroughly tested before attempting to use in a production environment.

To show the ESXi host status, you will need to specify a vSphere Cluster running VSAN and use the following command:

./vsanHostStatus.pl --server vcenter55-1.primp-industries.com --username root --cluster VSAN-Cluster

As you can see this is an easy way to quickly get the health of ESXi host participating in the VSAN cluster.