Machine reservations must be requested together

[tralfamadude]

In EC2, a batch of instances can be requested together, but hosts are instantiated one at a time. This slows down the provisioning process and reduces the likelihood that machines are co-located.

Note that ec2-describe-instances will show batches as a single RESERVATION which helps keep things organized.

[tralfamadude]

An example of the speed difference between reserve-all-at-once verses one-at-a-time:

The Hadoop ec2 bash scripts can bring up a 24 node cluster in about 20 minutes.

Poolparty (in Sept. 2009) required about 65 minutes to start up a 24 node cluster (tested with a static image needing no installations).

[auser]

This is implemented now to request the minimum number of instances at once.