Last week at VMworld 2013, VMware announced the release of vSphere 5.5 which includes a variety of exciting new features. One of the most anticipated feature introduced in this release is VMware Virtual SAN (VSAN) which will be available initially as a public beta. One question that I heard repeatedly throughout the VMworld conference was whether it would be possible to test VSAN in a nested ESXi environment? The answer is absolutely! This is a great way to learn about VSAN and how works from a functional perspective before procuring the necessary hardware.
Disclaimer: Running VSAN in a nested ESXi environment is not officially supported nor is it a replacement for actual testing on actual physical hardware.
Before getting started, I would highly recommend you check out the following resources from my good friend Cormac Hogan which includes a detailed VSAN walk through as well what looks to be an awesome series of articles on how VSAN works:
Requirements:
- Environment running either vSphere 5.1 or 5.5 and access to the vSphere Web Client.
Configuration:
Nested ESXi VM configured with the minimal resources:
- 2 vCPU
- 5GB Memory (ESXi 5.5 now requires a minimum of 4GB vs 2GB as with previous releases but VSAN requires minimum of 5 with recommended 6)
- 2GB Disk for ESXi 5.5 installation
- 4GB Disk for an "Emulated" SSD
- 8GB Disk for HDD
Easy Method:
Instead of having you go through the process of building a Nested ESXi VM with all the prerequisites that includes steps from here and here. I have pre-built a VSAN Nested ESXi VM template (217Kb) that you can just download and import into your environment and being the installation process.
Download either:
- Single VSAN Nested ESXi VM Template
- 3-Node VSAN Nested ESXi VM Template
- 32-Node VSAN Nested ESXi VM Template
and connect to your vCenter Server 5.1 or 5.5 using the vSphere Web Client and import the OVF into your environment (do not use the vSphere C# Client as the import does not persist VHV configuration). Once you have imported the VM, you can then mount the ESXi 5.5 ISO and begin the installation. All three VMDKs have been thin provisioned and you can change the capacity during deployment.
Slightly Harder Method:
If you wish to build the Nested ESXi VM yourself, then you can follow these instructions:
Step 1 - Create a new VM and when you get to the compatibility screen, select either "ESXi 5.1 or greater" or "ESXi 5.5 or greater" depending on the version of vSphere you are running
Step 2 - For the GuestOS select "Other" and "Other (64-bit)"
Step 3 - We will need to customize the following virtual hardware configuration:
- Change vCPU to 2
- Click on CPU drop down and enable "Expose hardware assisted virtualization to the guest OS"
- Change Memory to 4GB
- Change the initial VMDK to 2GB or whatever value you wish to use for ESXi installation
- Add second VMDK with 4GB or whatever value you wish to use for "emulated" SSD
- Add third VMDK with 8GB of whatever value you wish to use for the HDD
- Click on the VM Options tab at the top and select the "Advanced" drop down box. We will need to add the following entry scsi0:1.virtualSSD = 1 For more details please refer to this article
Step 4 - Click okay to provision the VM and once it has been deployed you will need to re-configure the guestOS to "VMware ESXi 5.x" using the vSphere C# Client for vSphere 5.1 or vSphere Web Client for vSphere 5.5. At this point, you will have the same VM image as in the Easy Method and you are now ready to install ESXi 5.5
When you install ESXi 5.5, you should see the following three disks as shown in the screenshot below, ensure you install ESXi on the 2GB disk:
Prior to enabling VSAN on the particular vSphere Cluster, make sure you enable the new VSAN traffic type on one of your VMkernel interfaces for each of your ESXi hosts, this is required for VSAN communication.
If all the prerequisites have been met, you can now easily enable VSAN by simply checking the VSAN box when editing the vSphere Cluster. In just a few minutes you should see diskgroups automatically created (assuming you selected Automatic mode) consuming both the emulated SSD and HDD and the creation of the vsanDatastore which will be available on all ESXi hosts within that vSphere Cluster.
You can also use the same method for emulating an SSD running in a Nested ESXi to functional test the new VMware Flash Read Cache (vFRC) feature.
