Tag Archives: ovf

VMware ovftool as Development Tool: Good and Bad Parts

If you want to export a virtual appliance for internal deployment, it’s quite easy. The vSphere Web Client or ovftool command line can take care of this easily. But it’s a different story to build a virtual appliance based software product, which should not only make it work, but also include product information.

Here are some information I learned and decisions I made from packaging an OVF product recently. Hope it would be useful for you. You can also check another post on how to compact the virtual disk for smallest OVA or VMDK.

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How to Build Smaller and Faster Virtual Appliance

While building a new server product of its own kind, we chose virtual appliance as the package. During the development phase, we configured thin disk to save space. But for our beta customers to try out, we decided to switch to thick disk for better performance as the product has to do lots of processing and heavy disk I/O. BTW, we still have a few slots for new beta customers with have large vSphere deployments. Please contact me if you are interested.

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Secret of vApp Template in vSphere

My colleagues and I had a discussion regarding the vApp template. After virtual machine template for virtual machine, you would expect vApp template for vApp and manage it in a similar way from the vSphere Client. But you cannot.

Most of us know that from vSphere Client, you have context menu item allowing you to convert a virtual machine to a template easily with a click. However you cannot find a similar menu item with a vApp. You can choose to convert a virtual machine inside a vApp, but then the converted template will jump out of the vApp container.

Can we have vApp template? The answer is we can, but in a different way.

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System Provisioning in Cloud Computing: From Theory to Tooling (part 2)

Application Provisioning

With the right system configuration in place, it’s time to install the applications. So why not use the same tools we used for the OS and middleware? Do we need yet another set of tools?”

It depends. You can use the same set of tools for middleware to install some applications. The middleware appears like an application to the OS as well. The difference is whether your application is stable enough and whether you need to customize per node. The tools like Puppet can be good for stable applications that can be deployed the same way across all nodes. If your application is still a work in progress and you need flexibility to tweak it, you need more specialized application provisioning tools.

The big technical difference between application and middleware provisioning tools is that application tools push the application to the nodes and remotely change anything as needed. The process is procedural.

The middleware provisioning tools normally have agents on the nodes to pull the software based on the prescribed configuration files. The process is declarative.

Beyond the “push” and “pull” difference, the application provisioning tools can also manage the lifecycles of applications (sometimes called services) distributed on different nodes with a single line of command or code. Given the nature of remote command dispatching framework, the application provisioning tool can do almost anything. If there has to be a limitation, it’s your imagination.

So if you develop applications by yourself, you most likely need application provisioning tools.

Let’s see what tools are there.

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System Provisioning in Cloud Computing: From Theory to Tooling (part 1)

Cloud computing is an evolutionary technology because it doesn’t change the computing stack at all. It simply distributes the stacks between the service providers and the users. In some sense, it is not as impactful as virtualization technology which introduced a new hypervisor layer in the computing stack and fundamentally changed people’s perception about computing with virtual machines.

But if you look closely at the latest IaaS clouds, they do leverage virtualization as a way to effectively and efficiently deploy systems. Inside one virtual machine, the computing stacks remain the same as before: from OS to middleware to application.

Keep in mind that the application is the end while the OS and middleware are the means. Customers care about applications more than the underlying infrastructure. As long as the infrastructure can support the applications, whatever the infrastructure might be is fine technically. Then the question would shift to the economic side: whatever is the most cost effective wins in infrastructure. That’s why Linux gains more shares in the cloud than in traditional IT shops.

To get to the end, you have to take a mean. In the IaaS cloud, you have to install the underlying OS and middleware before you can run your application. For the PaaS cloud, you can get away from that by focusing on application provisioning.

OS Provisioning

Remember, the software stack inside a virtual machine doesn’t change. It needs OS, middleware and application installed and configured before the application can work.

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How to Import and Export OVF Packages

This article is based on a similar one at vSphere Java API home page. At that time, one of VMware community members sent me an email for samples of using OvfManager APIs. Then I went to office on a Saturday writing two samples, which have been validated by several folks as “working” samples.

The purpose of the samples are to illustrate the vSphere APIs. Let’s take a look at them one by one.

First, ExportOvfToLocal.java. This sample shows how to download either a VM or vApp to your local machine. The typical flow is:

  • Find the VM or vApp
  • Call their exportVm() or exportVApp() methods and get HttpNfcLease
  • Set lease time out
  • Wait for HttpNfcLease until it’s ready
  • From the HttpNfcLease.info property, find the all URLs from which you download the vmdk files
  • Call OvfManager.createDescriptor() API to create the content of ovf and save it to a file along with downloaded vmdk files.
  • Release the lease by calling httpNfcLeaseComplete() method
Posted in vSphere API | Also tagged | 103 Responses


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.

Posted in Virtualization | Also tagged , | 3 Responses

    My company has created products like vSearch ("Super vCenter"), vijavaNG APIs, EAM APIs, ICE tool. We also help clients with virtualization and cloud computing on customized development, training. Should you, or someone you know, need these products and services, please feel free to contact me: steve __AT__ doublecloud.org.

    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.