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VMware nested easter egg

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It is only fitting that if a VMware Engineer adds a hidden easter egg, that it would of course contain another nested easter egg! For those of you who are not familiar with the vPong easter egg, Raphael Schitz wrote an article about a year ago regarding this little nugget which is when I first learned about this as well.

The easter egg allows you to play a game of old school pong using either VMware Fusion, Workstation, Player and it even works on vSphere. To enable this easter egg, you just need to mount a 0 byte floppy image located on your desktop (not a datastore) to a virtual machine and power it up.

Here is a screenshot of mounting a dummy floppy image which I created using the "touch" command on my Mac OS X system and connecting it to a Fusion VM:

Once you power on the VM, you should now see a game of vPong in the VM console which you can then play against the computer using your mouse.

One would think the easter egg stops there, but nope, there is actually more. If you click into the VM console and type the word "pride" (all lower case), you will see that the black/white vPong game will now change to color! To disable the color, you just need to type the word "pride" again and it will go back to black/white.

I thought this was actually pretty cool and thanks to Regis Duchesne for sharing this tidbit! So the next time you are bored, you can always kill some time with the classic black/white pong or go for the more colorful version 🙂

How to quickly setup and test VMware VSAN (Virtual SAN) using Nested ESXi

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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:

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.

Ravello: An interesting solution using Nested Virtualization

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As many of you know, I am a huge fan of VMware Nested Virtualization and I am always interested to learn how customers and partners are using this technology to help enable them to solve interesting problems. I recently met up with a startup company called Ravello who has a product that leverages Nested Virtualization in a very unique way.

Note: Ravello is not the only company using Nested Virtualization in interesting ways. Bromium, another startup in the security space, is also doing interesting things with Nested Virtualization.

Ravello is a SaaS solution that allows you to take an existing VMware or KVM virtual machine and without any modifications to that VM, run it on a variety of public cloud infrastructures including Amazon EC2, HP Cloud, Rackspace and even private clouds that are running on vCloud Director (support coming soon). Ravello is basically "normalizing" the VM by virtualizing it in their Cloud Application Hypervisor so that it can run on any cloud infrastructure.  From the diagram below, the unmodified VM is actually running inside of another VM which runs a flavor of Linux. This Linux VM loads up their HVX Hypervisor and is running on one of the public cloud infrastructures.

Similar to a regular hypervisor, HVX provides an abstraction, but instead of the underlying physical hardware it abstracts away the underlying cloud infrastructure. The HVX hypervisor provides the following three core capabilities:

  • Presents a set of virtual hardware that is compatible with VMware ESXi, KVM and XEN virtual machines
  • Virtual networking layer that is a secure L2 overlay on top of the cloud infrastructure L3 networking using a protocol similar to GRE but running over UDP
  • Cloud storage abstraction that provides storage to the VM through Ravello Image Store that can be back-ended by Amazon S3, CloudFiles or even block/NFS volumes

My first thought after hearing how Ravello works, is that this is pretty neat! Of course the next logical question that I am sure most of you are asking is how is the performance? We know that running one level of Nested Virtualization will incur some performance penalty and this will continue with additional levels of Nested Virtualization. Ravello is also not leveraging Hardware-Assisted Virtualization but Binary Translation (a technique developed by VMware) as that can not be guaranteed to be available on all cloud infrastructures. In addition to Binary Translation, they are also using various techniques such as caching and chaining translated code, fast shadow MMU, direct execution of user space code and few others to efficiently run in a nested environment.

I was told that performance was still pretty good and sometimes even out performing regular cloud infrastructures. There was no mention of specific applications or performance numbers, so I guess this is something customers will need to validate in their own environment. I am also interested to see what the overhead is by doing two-levels of Nested Virtualization and what impact that has to the guestOS and more importantly, the applications. To be fair, Ravello's current target audience is Dev/Test workloads, so performance may not be the most critical factor. They also provide two modes of deployment based on cost optimized or performance and if the latter is selected, overcommitment of resources or consolidation will not be used.

Overall, I thought Ravello's solution was pretty interesting and could benefit some customers looking to run their workloads in other public cloud infrastructures. I think performance is just one of the things customers will need to consider but also how do they go about managing and operating this new VM container and how tightly integrated is Ravello with the VMware platform or other hypervisors for that matter. Though the VM and the underlying applications does not need to change, what operational challenges does this introduce to administrators? 

Ravello also recently presented their HVX Cloud Application Hypervisor at a recent USENIX conference and you can find more details in their presentation called HVX Virtualizing Cloud along with their research paper which can be found here.

One thing that I did want to point out after watching the presentation is that one of the presenter mentioned that their HVX nested hypervisor runs more efficiently than any other hypervisor out there and that others would require things like Intel's VMSC Shadowing feature to be comparable. I can not speak for other hypervisors, but when running VMware Hypervisors on top of our ESXi Hypervisor, our hypervisor has already been optimized for VMREAD/VMEXITS and Intel's VMSC Shadowing feature would only benefit slightly. You can read more about those techniques in this blog article.

Ravello will be at VMworld US booth #425 and I will probably drop by for a demo to see their solution in action.