Nova boot from volume doesn't account for disk correctly

[Ed Balduf]

When you boot a nova instance from a volume (from Cinder) using the following command

nova boot --flavor 6 --block-device source=image,id=$SRCIMAGEUUID,dest=volume,size=10,shutdown=remove,bootindex=0 --key-name $KEYNAME testbfv$x

The disk accounting is not handled correctly and errors out with this log message

2016-07-13 12:33:30.340 DEBUG nova.scheduler.filters.disk_filter [req-6a2c44a2-0912-4e2f-8dae-0005b19656ea demo demo] (devstack-mitaka -compute.pm.solidfire.net, devstack-mitaka-compute.pm.solidfire.net) ram: 3215MB disk: 4096MB io_ops: 2 instances: 2 does not have 20480 MB usable disk, it only has 4096.0 MB usable disk. from (pid=28366) host_passes /opt/stack/new/nova/nova/scheduler/filters/disk_filter.py:55

nova hypervisor-show before creating instances (4 @ 10GB each)

| free_disk_gb | 44 |

Then create 4 (on this hypervisor) instance at 10Gb each nova hypervisor-show shows this:

| free_disk_gb | 4 |

Since these are Cinder volumes, they should not count against the Hypervisor disks space.

This testing was done against Mitaka devstack.

[Sean McGinnis (sean-mcginnis)]

Possible duplicate of this: https://bugs.launchpad.net/nova/+bug/1469179