Install tomcat on Google app engine?

Question

I am pretty new to this whole idea of cloud and started of with Google app engine. I was able to create the basic 'hello world' program.

When i tried to understand the difference between a cloud and a server I learned that Cloud is where you have an access to virtual instance created exclusively for you and you are free to choose and install software of your choice.

But I don't see such an option with Google-cloud/app-engine. What if I have a tom-cat based application server which I would like to deploy on a cloud? Will Google app engine be of any help or should I try other cloud service providers such as Amazon EC2, hp cloud etc?

/DJ

Answer 1

The cloud type that you are referring to is called Infrastructure as a Service cloud.

OTOH, Google App Engine is Platform as a Service cloud.

The difference is that IaaS are a bunch of virtual machines that you need to setup yourself (OS + app stack), while PaaS typically comes with it's own API, where you write your app against the API and the rest (sw stack + scalability) is taken care of.

AppEngine comes with it's own servlet container (Tomcat is also a servlet container), so from this standpoint you could use your code on AppEngine. But the problem lies elsewhere: AppEngine imposes a set of limitation on the apps:

1. app must use GAE provided databases.
2. app can not write to filesystem
3. app can not have listening sockets
4. requests must finish in 60 seconds (e.g. no Comet or WebSockets -> no push)

You might want to review the FAQ.

Answer 2

To add to Peter's excellent answer, note that Google also has an IaaS service called Google Compute Engine.

Answer 3

Regarding other cloud query- Before you start with cloud you might once try other options. Currently deploying application in almost all services are very easy. few of them are- Jelastic , Heroku , rackspace , nimbus , openshift etc.

Difference between cloud and server is very well explained already.

Since you mentioned about tomcat based application , I have worked with Jelastic for the same and found very easy to implement.

• http://jelastic.com/docs/tomcat
  http://jelastic.com/tomcat-hosting

Try all possible option , it will help you more .