Monthly Archives: June 2011

Why Virtual Machine Not Found?

I saw a new bug (Intermittent ManagedObjectNotFound on VirtualMachine.getConf) filed in the open source VI Java API project today:

It looks like sometimes VirtualMachine.getConfig() returns null, but other times it throws:
Caused by: java.lang.RuntimeException: com.vmware.vim25.ManagedObjectNotFound
at com.vmware.vim25.mo.ManagedObject.retrieveObjectProperties(ManagedObject.java:158)
at com.vmware.vim25.mo.ManagedObject.getCurrentProperty(ManagedObject.java:179)
at com.vmware.vim25.mo.VirtualMachine.getConfig(VirtualMachine.java:55)

As the vSphere API reference points out,

Posted in vSphere API | Tagged , , | 2 Responses

Moving Virtual Machine Back From Distributed Virtual Switch

After blogging about moving virtual machines from a standard virtual switch to a distributed virtual switch, I saw a new question in VI Java API forum on how to roll it back. Technically, I don’t see any reason why one should switch back because using distributed virtual switch gives you a lot of benefits. But the decision is not mine but yours. Whatever you want to do, we help do it easily.

The method involved is

Posted in vSphere API | Tagged , , , | 4 Responses

Is serverGuid Attribute Really Needed in vSphere?

If you have paid close attention to the SOAP messages recorded by Oynx, you may have noticed that there is an extra attribute called “serverGuid” in a ManagedObjectReference. The following is copied from my previous posting “Moving Virtual Machine to Distributed Virtual Switch”.

<_this xsi:type=”ManagedObjectReference” type=”VirtualMachine” serverGuid=”BA9CE658-75F7-4A99-ACE6-99EB1376B94A”>vm-134</_this>

Note that this SOAP request message is from a vSphere Client. In VIJava API or other language binding, there is no such an attribute. You may wonder,

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In Praise of Static Methods

In object-oriented programming, static methods are the methods that are defined with static keyword. They don’t have access to non-static instance variables. This very limitation can be an easy cure for many programming pitfalls I’ve seen over the years.

  • A static methods prevents you from using instance variables for passing information around, for example, as parameters to or as result from it. As a general rule, you should not define an instance variable if it’s not an intrinsic property of a class or type. It may seem obvious,
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ManagedObjectReference vs ManagedObject

One of the most common confusions that a newcomer has while learning vSphere API is the ManagedObjectReference, a.k.a MOR. If you read the API Reference, you will find a lot of them. Recently there was a question poping in the open source VIJava API forum. So I think it is worth explaining it here.

There are two major types in the vSphere API: managed object types are for these objects on the server side only; and data object types for properties, parameters, and results, which can be send back and forth between client and server. The MOR is a data object type, but used to represent managed objects living on server side. If you are familiar with C/C++ programming, you can think of it as pointer in some sense. Even better,

Posted in vSphere API | Tagged , | 28 Responses

Most Used API in vSphere

Yesterday I blogged about the least used API in VMware vSphere. This naturally leads to another question, “what is the most used API in vSphere?” It’s a harder question than the “least” one, because for the latter I can be very sure that zero is the lowest possible usage. If that API is not the least, it must be one of the least.

Before we try to figure out the answer, let’s clarify a bit the “most used.” Does it mean the one that is called the most times? Does it mean the one that is touched and used by most developers?

Posted in vSphere API | Tagged , , | 1 Response

Least Used API in vSphere

Last week I was extremely busy working on the VI(vSphere) Java API 3.0 (codename: Crescendo) whose main theme to support the next release of vSphere. To my surprise, I caught on an API that should have been included in vSphere Java API 2.1 but somehow omitted. Even surprised to me is that no one has reported to me via our sourceforge.net tracker.

I think the conclusion can only be one –

Posted in vSphere API | Tagged , , | 1 Response

Moving Virtual Machine to Distributed Virtual Switch

The distributed virtual switch introduced in vSphere 4 has many benefits over the traditional switch. For one thing, you no longer have possible glitches with live migrating virtual machines from one host to another using traditional switches, and all your port settings go with your virtual machines.

If you have virtual machines using traditional switches, you can easily move them to new distributed virtual switches. The rest of this article explains how to achieve this.

You can use the

Posted in vSphere API | Tagged , , , | 3 Responses

Tagging: What’s the Alternative?

After my last post Tagging: An invisible feature in vSphere, William Lam quickly followed up with another post in his blog, arguing vSphere Tagging Feature Not So Invisible. He made his case by showing how you can actually add and remove tags using addTag() and removeTag() method via vSphere MOB. You can definitely play with your test environment, but please do not mess up with any existing tags in your production environment.

Although you can do that via MOB, it’s not the officially supported way (BTW, this should not be taken as show stopper. After all,

Posted in vSphere API | Tagged , , | 5 Responses

Tagging: An Invisible Feature in vSphere

If you are familiar with social media or research papers, you must know tagging already – You use keywords to label an entity, be it a blog post, an article, or something else, so that it can be easily searched out. So it’s a very useful feature in managing information.

In vSphere 4.0, VMware added tagging capabilities to the managed entities. According to the API reference of 4.1, it’s still an experimental feature and

Posted in vSphere API | Tagged , , , | 4 Responses

A Trick With OptionManager in vSphere API

There was recently a question in the open source VI Java API forum regarding the OptionManager. As you may have known, the OptionManager is used to manage key value pairs, for example, the “VMFS3.HardwareAcceleratedLocking” is a key as shown in the code included in the question. Somehow the code to set the key, as shown below, doesn’t work with com.vmware.vim25.InvalidArgument exception.

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Recorded Tech Talks Are Ready!

After publishing the tech talk slides, I am happy to announce that the record is ready now. If you have missed the onsite or online session, or simply want to watch it again, please feel free to click here. Note that you will need Adobe Flash 10.1 or higher to view the recording.

Many thanks to my colleague Luke Kilpatrick (@lkilpatrick) for helping with online streaming and recording, and Matt Dhuyvetter for setting up the top quality audio feeds!

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IT Automation: A Cognitive Perspective

Recently I stumbled at a book Things That Make Us Smart by one of my favorite authors Donald Norman. In the book, he shared many insights on the complex human machine interactions, “arguing for the development of machines that fit our minds, rather than minds that must conform to the machine.” By the way, I highly recommend his another book The Design of Everyday Things.

Because I just blogged about IT automation, I still have that topic on my mind. So when I read the book, I did quite a lot of reflective thinking around IT automation. In general, I feel

Posted in Cloud Computing, Virtualization | Tagged , | 1 Response

A Powerless Feature in VMware vSphere

Distributed Power Management (DPM) is a powerful (powerless, really) feature can reduce host power consumption in a DRS cluster. It works in either manual mode or automatic mode only when DRS is enabled. DPM can place idle hosts into standby mode, or awaken them from standby when more resources are needed.

Like most of the features in vSphere, you can manage them with the APIs. A recent question at the open source vSphere Java API forum asks how to get hold of the DpmBehavior data object. This seems easy but

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    Me: Steve Jin, VMware vExpert who authored the VMware VI and vSphere SDK by Prentice Hall, and created the de factor open source vSphere Java API while working at VMware engineering. Companies like Cisco, EMC, NetApp, HP, Dell, VMware, are among the users of the API and other tools I developed for their products, internal IT orchestration, and test automation.