Need help attaching a block device as second disk to a VM

Product Support Installation & Configuration
1

Hi,
I am following the doc Raw Device Mapping (RDM) Datastore — OpenNebula 6.2.2 documentation
to attach a block device as a second disk to an existing VM.

its throwing this error. can you please shed some light on this error message and point me to a fix?

Failed to execute virtualization driver operation: attach_disk.
[Z0][VMM][E]: ATTACHDISK: ERROR: attach_disk: Command “set -e -o pipefail virsh --connect qemu:///system attach-device 3dbd3c37-26d3-4fa5-9b08-51232f54fcb <( cat <<EOT EOT )” failed: error: Failed to attach device from /dev/fd/63 error: internal error: unable to execute QEMU command ‘blockdev-add’: ‘file’ driver requires ‘/dev/vg-nvme0n1/lv-vm1-disk1’ to be a regular file Could not attach /dev/vg-nvme0n1/lv-vm1-disk1 (sdb) to 3dbd3c37-26d3-4fa5-9b08-xxx ExitCode: 1

–
I also tried changing /dev/vg-nvme0n1/lv-vm1-disk1 to /dev/sdb (assuming that is the block device reference used for the VM itself and not the node).

getting the same error

internal error: unable to execute QEMU command ‘blockdev-add’: ‘file’ driver requires ‘/dev/sdb’ to be a regular file Could not attach /dev/sdb (sdb)

it will be helpful to understand the error itself.
what we are trying to do is adding a block device. but OpenNebula expect is to be a regular file?

keywords: “block device”, “raw”, “LVM”, “Unknown disk name”, “add additional disk to the VM”, “add additional disk to the VM while its running”

Thanks

2

Hey, did you try creating the image with the CLI?

oneimage create -d ${DATASTORE_ID} --name lv-vm1-disk1 --source /dev/vg-nvme0n1/lv-vm1-disk1 --driver raw --prefix vd --persistent --type OS --size 0MB
3

I tried the command line.
oneimage create -d 117 --name lv-vm1-disk1 --source /dev/vg-nvme0n1/lv-vm1-disk1 --driver raw --prefix vd --persistent --type OS --size 0MB

I get the below error message:
invalid option: --driver

got some additional inputs and questions.

the datastore “117” is an image datasore which is created like this.

cat rdm.conf
NAME = rdm_vm1_disk1
TYPE = “IMAGE_DS”
DS_MAD = “dev”
TM_MAD = “dev”
DISK_TYPE = “BLOCK”
onedatastore create rdm.conf

  • we are expecting this block storage to be provisioned in the local disk of the node. (its not shared storage like NAS/SAN).
  • attach a raw device to the VM directly. (VM will create the filesystem)
  • the raw device is a logical volume (lvm) on the node

I am in the right path?

4

What is the opennebula version?

5

opennebula version is 6.10.0.1

6

According to the CLI help, you should use --format raw instead of --driver raw:

...
## OPTIONS
     -d, --datastore id|name   Selects the datastore
     --description description Description for the new Image
     --disk_type disk_type     Type of the image BLOCK, CDROM, RBD or FILE (for
                               others, check the documentation)
     --dry                     Just print the template
     --format format           Format of the image (raw, qcow2, ...)
     --fs filesystem           Filesystem to format the image (ext4, xfs, ...)
     --name name               Name of the new image
     --no_check_capacity       Do not check Datastore capacity, only for admins.
     --path path               Path of the image file
...

Also, --disk_type BLOCK should register the device as a block device so ONE knows it should be presented to libvirt as such.

7

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.