Looking for a place to host my own home grown apps, I came across an interesting presentation about using Windows Azure cloud to run Tomcat and a JVM in the Microsoft cloud solution. See Building Java Applications with Windows Azure
The presentation basically says Azure can run any native code, which means java.exe and tomcat. Native programs that runs off a batch file with no specific registry key or lowlevel system dependencies or installers are more likely to run in Azure.
Azure has worker roles and web roles. Web roles are used for hosted apps with .net/php and IIS and not used here, however the worker role is used to run native code. It can be bound to a network port (ie port 80)
The Microsoft support comes in with an Eclipse plugin to access your resources in the cloud from within Eclipse. There is a jar that wraps up the RESTful interface to Azure that your app would normally use to access the clouds resources with Java helper classes and provides some other .NET helper classes.
It also comes with some helper stuff to setup Tomcat – ‘Tomcat Solution Accelerator’ – to configure Tomcat to make it very light in terms of OS dependencies. It also has monitoring of Tomcat to let Azure know to restart the app if it fails and also help indicate to MS there is a problem with the particular server that instance in their cloud is perhaps not working as it should.
I do like that you get to choose the versions of Tomcat and Java you want, and there doesn’t seem to be much of a reason you couldn’t apply this to other languages and appserver environments. (Grails/Jetty? – and hopefully Glassfish, but that may need a bit more config work to pack it up and install on the cloud). That last point sounds a bit negative, you could probably get a service on a VM linux host that means you dont have to fudge around so much, but still the novelty polyglot value of having JVM and .NET in the same cloud environment may actually outweigh the negative of the DIY setup. The presentation explains how the Tomcat is packaged and shows the contents of the packaging scripts to give you an understanding of how to do the same for another appserver.
One nice thing about the Azure platform itself is that you have production and staging slots – you can have a production app in the cloud, and also a staging version too – and swap them over when you are happy with Staging.
The other aspect is the queues/worker facility to allow for concurrency when running your app across multiple nodes, asynchronous architectures and scalability.
To try it out, you’ll get free access to Azure while its in CTP status (till Jan 09), and then MS will start asking for money. Apparently, Dominoes pizza is testing out their next version of their ordering webapp on the platform, if you wanted a vote of confidence too
Azure Java SDK available here: windowsazure4j.org