Migrate-volume-block-migration
Add Support for Volume migration during Live (block) migration
External Specification:
Add --block_device_mapping parameter to "nova live-migration --block_migrate" command.
The entire format of the command will be like this
`nova live-migration --block_migrate --block_device_mapping vda=1:::0, --block_device_mapping vdb=...(all attached EBS volumes) <instance_name> <name_of_destination_compute_node>`
Administrator has to specify --block_device_mapping parameters for all volumes attached to the instance.
Follow the existing format to specify block device mapping
`--block_device_mapping <device_name>=<a>::<c>:<d>`
<device_name>: device name referred from the instance
<a>: destination volume name (Note: MUST specify an existing volume, must be same size to the source volume)
<b>: N/A
<c>: N/A or size of the volume
<d>: 0:Do not delete the source volume, 1:delete the source volume
Note: Volumes on the destination volume node need to be created before the migration takes place. The migration could ensure copying the data onto the destination volumes.