[cs615asa] Some questions.

[czhang13]

>> In this example, if ec2-run-instance does not get key option,
>> then what key is used in ssh?
>
> Whatever the user has specified in their ~/.ssh/config file (or none, 
> if
> they don't have it set up correctly).
>
> -Jan
> _______________________________________________

But the aws document said that
launching public images without a key pair ID will leave them 
inaccessible.

Chao