Interacting with Block Storage (1.5.1)

The Block Storage Service in Eucalyptus is interface compatible with Amazon's Elastic Block Store. You can therefore use ec2 commands to interact with Eucalyptus' Block Storage. You will need to download and install EC2 API tools in order to use Block Storage.

The following operations are possible,

1. Creating volumes

You may create a volume either from scratch or from an existing snapshot.

ec2-create-volume -s <size> -z <zone>

where <size> is the size in GB and <zone> is the availability zones you wish to create the volume in (use ec2-describe-availability-zones to discover zones).

For instance,

ec2-create-volume -s 1 -z myzone

will create a 1GB volume in the availability zone "myzone"

To create a volume from a snapshot,

ec2-create-volume --snapshot <snapshot id> -z <zone>

where <snapshot id> is the unique identifier for a snapshot and <zone> is the availability zone you wish to create the volume in.

For instance,

ec2-create-volume --snapshot snap-EF4323 -z myzone

will create a volume from the snapshot "snap-EF4323" in the zone "myzone"

2. Query the status of volumes

ec2-describe-volumes

Volumes marked "available" are ready for use.

3. Attaching a volume

You can attach volumes to existing instances (that have been started with ec2-run-instances). You may attach a volume to only one instance at a time.

ec2-attach-volume <volume id> -i <instance id> -d <local device name>

where <volume id> is the unique identifier for a volume (vol-XXXX), <instance id> is a unique instance identifier and <local device name> is the name of the local device in the guest VM.

For instance,

ec2-attach-volume vol-FG6578 -i i-345678 -d /dev/sdb

will attach the previously unattached volume "vol-FG6578" to instance "i-345678" with the local device name "/dev/sdb"

4. Detaching a volume

ec2-detach-volume <volume id>

where <volume id> is the unique identifier for a previously attached volume (vol-XXXX).

For instance,

ec2-detach-volume vol-FG6578

will detach volume "vol-FG6578"

Important! The user of the instance is responsible for making sure that the block device is unmounted before a detach. Detach cannot ensure the consistency of user data if the user detaches a volume that is in use.

5. Deleting a volume

ec2-delete-volume <volume id>

where <volume id> is the unique identifier for a volume (vol-XXXX).

6. Creating a snapshot from a volume

You can snapshot a volume so that you can create volumes in the future from the snapshot.

ec2-create-snapshot <volume id>

where <volume id> is the unique identifier for a volume (vol-XXXX).

For instance,

ec2-create-snapshot vol-GH4342

will snapshot the volume "vol-GH4342"

The volume to be snapshotted needs to be "available" or "in-use." You cannot snapshot a volume that is in the "creating" state.

7. Querying the status of snapshots

ec2-describe-snapshots

You may create volumes from snapshots that are marked "completed."

8. Deleting a snapshot

ec2-delete-snapshot <snapshot id>

where <snapshot id> is the unique identifier for a snapshot.