block device examples updated

[gmiranda23]

The block device examples are incorrect. Adjusted them to reflect a useable config.

[tyler-ball]

Hey @gmiranda23 - I actually get errors trying to use this PR. What is the error you're seeing?

Although, while troubleshooting I did come across an unexpected exception trying to call logger from the InstanceGenerator class

[gmiranda23]

It's not so much an error as misleading info. I don't typically come across EBS volumes with block device trailing numbers for anything other than root volumes. And even then, most newer instance types have problems with them. I wasn't quite sure why, but your question prompted me to look it up.

I got some clarification on this from the EBS Block Device Mapping Concepts doc.

"Trailing numbers on device names can sometimes be used, but may cause conflicts. [...] Hardware virtual machine (HVM) AMIs don't support the use of trailing numbers on device names (xvd[a-p][1-15])."

So perhaps to make that usage point, the example should have one definition with a trailing device number and one without?

[tyler-ball]

If it is suggested to use non-numbered device names, then I'm all for updating the documentation. I'm not very familiar with the concept of disc device naming.

I would just like to make sure the example does work. Can you update the AMIs in the example at the bottom of the README so specifying /dev/sda instead of /dev/sda1 will create it correctly? Perhaps just use Ubuntu 15.04 HVM (ami-cf09e8a4) and Centos 7 HVM (ami-96a818fe). Will you try those AMIs and test the full example to make sure it works?

If you update the root device mapping, TK should issue an info level log message stating this.

[gmiranda23]

After some research, I put together a full working .kitchen.yml example using non-standard settings (us-west-2), with updated fields where appropriate, a mix of using platforms defined in amis.json, and custom platforms with different settings. Makes usage described in #153 clear.

[tyler-ball]

I know this was broken earlier, but I would like to encourage people to use the single-letter form of this config to DRY this yaml up a bit. Would you try b with the latest version of kitchen-ec2 (0.9.5+)?

[tyler-ball]

Other than my last minor comment, this is looking awesome. Thanks @gmiranda23! Once that is addressed I'll merge this.

[gmiranda23]

I updated it to the long format because single letter was busted. I agree that's a better form. Tested on kitchen-ec2 0.9.5 and it works again. LGTM!