Why we switched from Google App Engine to EC2

There have been a number of posts attacking App Engine recently, and a lot of good discussions have come out of them. The two things issues that seem to get brought up most are app design and reliability.

- Reliability: App Engine reliability used to be horrible, but it's getting better.

GAE was the first service I ever developed for where reliability was an issue. I've hosted apps on Linode, Slicehost, EC2, and my experience with those companies caused me to dismiss claims of downtime and the importance of an SLA.

Nothing sucks more then seeing your system go down for days at a time, and not being able to do anything about it. I'm glad that GAE is addressing this issue, but I'd be wary of running anything commercial on their services without buying a business plan.

- App Design: Pretty much everyone agrees that you have to write applications the way GAE wants you to, or you'll fail.

The built in GAE Python library is great for writing simple, highly scalable websites, but it's too limited to develop complex applications on. Our application has over 20KLOC and uses numerous third party libraries. In practice, we found that it was difficult and time-consuming to write our application without turning to a more established framework like Django. We were also concerned with the vendor lock-in that would be caused by building on library that could only be run on GAE. Projects like TyphoonAE (http://code.google.com/p/typhoonae/) are starting to make this less of an issue, but they aren't mature enough to provide an exit strategy.

We built our application on appenginepatch, a third party port of Django to GAE. Django was not designed to run on a non-relational DB, and GAE was not designed to handle a heavy framework like Django. Our decision to build things our application on Django ultimately lead to most of our problems, but eventually saved our skin when we decided to switch away from GAE.

I'm a huge EC2 zealot (and customer) - but I'm also intrigued by the concepts behind App Engine. However, there has been a spate of negative posts such as these around App Engine.

I also would like to hear from someone who is successfully using App Engine for a large scale project, and what their lessons learned, best practices are.

I'm one of those "right tool for the right job" type of person so I'd love to see where App engine might fit in some of my business' architecture.

Google should get it, in that they need to offer support if they want to run this kind of business. But customers should also know that Google doesn't do support, and they will need support, so GAE is probably not a good fit.

If that's right, I agree as well.

Yes, you still have to adapt to the AppEngine way of doing things. But the adaptation is much simpler ... and I completely dislike the way webapp does a lot of things judging from the examples Google provides. I like my world nice and full of free-floating functions. Wrapping things into nearly meaningless objects hurts my brain.