Add describeAvailabilityZones and gradle.properties for jvm heap size

[Davinder2me]

Add describeAvailabilityZones and gradle.properties for jvm heap size.

For large number of instances: jetty failed. Do you have fix that? By Adding the gradle jvm heap size helped little. However, still, it is still failing large numbers of instances

[maxiaohao]

Hi,
Thanks for the cool PR - I've reviewed it and merged it.
On the large number of inst failure, I think it relates to the thread model per instance - see class AbstractMockEc2Instance, which makes use of java.util.Timer. That means every mock EC2 instance runs in a separate jvm thread, which consumes considerable amount of resources and large number of threads could easily fail the jvm.
So I think, if possible, we may need to explore further options that can substitute the current java.util.Timer based model and have the performance improved. (actually I had such a plan earlier).
I am still too busy to look into this interesting issue and if you can do that, that would be great!
And I may have a chance to dip into that next weekend.

Thank you!

[Davinder2me]

Hi,

Thanks for merging my pull request. However on large number of instances, I tried with ExecutorService instance of Timer, that did not help. However by changing heap size, i can create 30 K instances from earlier 5 K. Issue look like related to ThreadCount or File Count that OS can support.

I will try to see if we can improve that number to 50K.

Thanks
Davinder

[maxiaohao]

That's great!
And I've filed that in the new issue #40 and let's try to get it improved.
Thank you.