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Archive for April, 2010

OVF vs. VMDK

April 6th, 2010 2 comments

OVF stands for Open Virtualization Format, a platform independent, extensible packaging and distribution format for virtual machines. It’s now a DMTF standard.

VMDK stands for Virtual Machine Disk, a format that encodes a single virtual disk for a virtual machine. It’s proprietary by VMware but whose format is publicly documented by the company. You can use VDDK to manipulate the VMDKs.

Categories: Virtualization Tags: , ,

Cloud Computing: How Much Can It Change IT?

April 5th, 2010 3 comments

There have been many debates on the potentials of cloud computing and how it can change the IT. Some say it’s the future of IT and everyone and every enterprise will have to go with it; others say it’s a hype and just another name for already vanished on-demand computing, utility computing.

So which will be the trend? Or should we take a middle ground between these two?

While predicting the future, we tend to look back and try to leverage historical data. I bet you have seen many such analysis that draw different conclusions. History can be interpreted differently.

In this article, I would like to take a different approach — make an analogy between cloud computing and office rental business, and then predict the future of cloud computing from what’s today in office rental business.

Technology wise, cloud computing and office rental are two totally different things. Business wise, they are actually very similar. Whatever benefits of cloud computing can be found in office rental, for example, no initial capital investment in building either office or data center.

Although new technology companies get started and make impact on many things, the fundamentals of business haven’t changed. You still use the same balance sheets to evaluate high tech companies just like the blue chip companies. When making decisions, companies base more on business than on technology. That’s why I can make a safe analogy here.

Categories: Cloud Computing Tags:

Slides From The Cloud Club March Meetup

April 2nd, 2010 No comments

Almost forget to report last Cloud Club meet-up which took place at Santa Clara Convention Center on the night of March 16. The meet-up was conveniently co-located with the CloudConnect 2010 Conference.

We had several great speakers from companies like Makara, Engine Yard, Heroku, Appirio, etc. As you can guess from the speakers’ company profiles, the theme of the meet-up was about PaaS. Each speaker had about 20 minutes to introduce their technologies.

Winners of the VMware Script-O-Mania Contest: Who, What, How and Why?

April 1st, 2010 No comments

The winners of the VMware Script-O-Mania contest was announced today by Pablo Roesch at VMware Developer Blog. Congratulations to Alan, William and Arnim who won the first three awards!

I just took some time to read these scripts even though PowerShell and Perl are not for me. Here I give you a brief introduction of the scripts, what vSphere APIs they used directly or indirectly, and why they topped the contest. Because vSphere API is based on Web Services, you can port the scripts to other languages like Java, .Net, whatever you feel comfortable with. If you want to port any of them using vSphere Java API, I am more than happy to include your contribution.

Note that the following comments are strictly my own opinions.

1. Who Created that VM ? – by Alan Renouf using PowerCLI

A script to add information back into the vSphere client, this script which is designed to run once a day (or more) as a scheduled task, will add a custom attribute to each VM with the creator and date created of that VM. A script to add information back into the vSphere client, this script which is designed to run once a day (or more) as a scheduled task, will add a custom attribute to each VM with the creator and date created of that VM.

Steve’s Comments:

Nice integration with the vSphere Client, making you almost doubt why it wasn’t there in the first place. Additional one liner scripts provide nice answers to the questions like who created the most VMs, how many VMs were created each month.

Introducing Security Model of VMware vSphere

April 1st, 2010 2 comments

This article introduces you the basic model and terminologies in vSphere security management, for example, privileges, permissions, roles, and how they are related to each other to secure vSphere. It helps you to better manage the vSphere and program the vSphere API. Much of the content is based on my book VMware VI and vSphere SDK by Prentice Hall.

In vSphere, the security model consists of three types of components: privileges, roles, and permissions.

Privileges

A privilege is the basic individual right required to perform an operation. It is statically defined and never changes in a single version of a product. Given the many operations in VI, there are many privileges (for example, the privilege to “power on a virtual machine”). These privileges are represented as strings separated by dots, such as VirtualMachine.Interact.PowerOn.

The operations and privileges are not one-to-one mapping. Many operations do share common privileges like System.View. Therefore, there are many fewer privileges defined than methods. In some exceptional cases, a method requires different privileges depending on the target it operates on and the nature of the operation. The CloneVM_Task() method, for example, requires VirtualMachine.Provisioning.Clone for cloning from one virtual machine to another, VirtualMachine.Provisioning.DeployTemplate for cloning from a template to a virtual machine, and so on.

Roles

The role groups privileges from a user’s perspective. A role is normally named and defined for a group of people who have common responsibilities in the system (for example, administrators). Each role can include zero to multiple privileges. The extreme cases are the predefined “Admin” roles, which by default, includes all the privileges and the NoAccess role, which includes no privileges.

Categories: vSphere API Tags: ,