Eucalyptus supports two different types of instances; instance store-backed instances and EBS-backed instances. This section describes EBS-backed instances.
With EBS-backed instances you are booting an instance from a volume rather than a bundled EMI image. The boot volume is created from a snapshot of a root device volume. The boot volume is persistent so changes to the instance are persistent.
Linux boot-from-EBS instances do not require EKI and ERI images like paravirtual instance store-backed instances.