Given the growing popularity of Hadoop, I decided to give it a try by myself. As normal, I searched for a tutorial first and got one by Yahoo, which is based on Hadoop 0.18.0 virtual machine. I knew the current stable version is 1.x, but that is OK because I just wanted to get a big picture and I didn’t want to refuse the convenience of ready-to-use Hadoop virtual machine.
Recently I started to build a stand-alone Java application. The first thing I thought of was to use Eclipse, which I have been using since 2000. As you may know, the Eclipse family has a framework called Eclipse RCP (Rich Client Platform) for building standalone application. In fact, Eclipse IDE is now built on top of the Eclipse RCP framework.
#7 Levarage vApp
vApp is a new addition to vSphere. It’s essentially a group of VMs that work together as a solution. You can manage them as a basic unit like a VM. It provides you higher level granularity for resource allocation and management.
This is an ideal container for your application if you have multiple virtual machines involved. They may or may not form a cluster, but are bundled together for a same goal.
The vApps are not only easily managed by the vSphere, but also imported and export as a bundle. Therefore you can easily move it without worrying what should be included while copying it.
VMware provides tools like VMware Studio using which you can create and configure vApps easily. The VMware Studio has Web based console, customization and build engine, build process automation with CLI (command line interface).
Other alternatives include:
#4 Scale Applications as Needed
Most time, people think scalability is to handle more workload when needed. This is true, but not enough. A truly scalable system should scale back. This is how you will save money. This is equally important as the first case where you get more revenue by serving more traffic.
There are different ways to scale:
- Up and down. This is unique in virtualized environment in which you adjust the memory or CPU allocation and use more or less of them instantly.
- Out & in. This means you include more machines either physical or virtual into your application.
You have to think over several architecture decision points:
This second part contains best practice No.1 ~ 3.
＃1 Move Up to Higher Level Software Stack
“If I have seen a little further it is by standing on the shoulders of Giants.”
Modern software development is all about leverage. You don’t want to build everything from bottom up. Whatever “giant shoulders” you can leverage, you should do so. Remember the keyword here is “giant shoulders.” You got to be selective on what is “a giant” and what is not, for the best quality of your system. Your application’s quality is a function of that of the systems underneath it.
The typical “giant shoulders” includes middleware, high level programming languages, tools. By leveraging these, you should expect your applications portable, and with much less code and higher developer productivity. The portability is very important when you want to deploy your applications in federated cloud environment.
I posted a short article after the cloud demo in VMworld 2009 keynotes. It’s reposted at SpringSource blog. The article introduced “DIY PaaS” concept which you could have a higher level of development platform inside your enterprise in a similar way as would you get from vendors like Google, but without vendor lock-in.
The “DIY PaaS” does not require you to use any specific platforms, middleware or framework. You could use any existing combination of systems on top of Java, .Net, Python, PHP. For example, you could use Java with Spring framework for building your web applications or enterprise integration frameworks. The choice is really yours, not of any vendors. When making a decision, you want to consider various factors like your team’s expertise and preference, total cost of software licenses, design constraints posted by for example existing investments on particular software.
Having decided the combination of software stack, you want to pack them into virtual machine templates that can be re-used by various teams. If you have multiple combinations, you can have multiple virtual machine templates in your catalog.
In general, you want as few templates as possible. Why?
Having less VM templates means less effort to build them, to manage, to upgrade, and to test. This might not seem like a big deal but could become a big deal in a longer term when you have to maintain multiple versions of these templates at the same time.
It also means less storage. vSphere has a special technology called linked clone. The new virtual machine doesn’t fully clone the disks, but links back to the template. If you have least templates, you can have a huge saving on the disk space. High quality storage can be very expensive.
Last but not least benefit is less memory. vSphere has memory page sharing technology which keeps one copy of same page contents, and converts others as pointers to the single copy. It’s only possible when you have identical memory pages. When you have virtual machines cloned from a same templates, the chance of identical memory pages increases dramatically.
There are several techniques to keep the least number of virtual machine templates:
With more data centers running on purely virtualized systems, more applications are therefore running on top of virtualized environment than ever before. These virtualized systems are interconnected with each other and become a cloud platform. Virtualization is the pre-requisite and starting point of the cloud computing at the IaaS level.
Many folks mentioned their presentations for VMware Partner Exchange in Las Vegas next month. Let me share mine here.
As you migth have guessed from the blog title, the presentation has a lot to do with both the cloud and application. My presentation title is “Architecting your applications for VMware Cloud.” I will discuss the challenges and opportunities the cloud brings in for application development, especially for the application architecture, and more importantly how to get it done.