EBS volumes

EBS volumes on Amazon can not be tagged with security groups like instances. Therefor, an EBS volume group object is used to automatically select free EBS volumes and attach them to cloud instances. When not enough volumes are found, new volumes are spawned with the settings/filters provided to the EBS volume group. E.G.:

pool :mypool do
  cloud :mycloud do
    using :ec2
    instances 1..5
    ebs_volumes do
       size 50
       device "/dev/sdi"
       snapshot_id "snap-a5b0c899"
    end
  end
end

This will create a cloud with each instance having an EBS volume of 50gb based on snapshot “snap-a5b0c899” and attached to device /dev/sdi. If matching EBS volumes are lying around unattached they will be used, if more volumes are needed they will be created.

Let’s go over the directives:

• ebs_volumes – declare a new EBS volume group, must be followed by a block defining group selectors
• size – have a wild guess
• device – the device used when attaching to instances
• snapshot_id – a snapshot used when creating new EBS volumes, may be omitted
• volumes "vol_id", "vol_id",... – use the specified volumes even if they don’t match the criteria.