[Qemu-discuss] Issue on qemu 1.5.0 with Glusterfs 3.4 native integration

[Olivier Mauras]

Hello,

I've compiled latest qemu 1.5.0 with glusterfs support using glusterfs 3.4 beta3 (also tried beta2).
While qemu-img creates an image on my gluster volume without a itch, it seems that qemu is unable to start a VM with a gluster drive.

The server is running Scientific Linux 6.4 with a custom grsecurity kernel 3.9.6, qemu 1.5.0 and libvirt 1.0.6.

Here's how i proceeded.

address@hidden ~]# gluster volume create vol0 bbox:/pool/gluster
volume create: vol0: success: please start the volume to access data

address@hidden ~]# gluster volume start vol0
volume start: vol0: success

address@hidden ~]# gluster volume info vol0                                                                                                                                                                                                                                          
 
Volume Name: vol0
Type: Distribute
Volume ID: 85b6569c-7523-47b0-b8e3-8a96089733ac
Status: Started
Number of Bricks: 1
Transport-type: tcp
Bricks:
Brick1: bbox:/pool/gluster

address@hidden ~]# qemu-img create gluster://127.0.0.1/vol0/test0.img 10G
Formatting 'gluster://127.0.0.1/vol0/test0.img', fmt=raw size=10737418240

Mounting it to ensure the file is here
address@hidden ~]# mount -t glusterfs bbox:/vol0 /mnt/
address@hidden ~]# ll -h /mnt/
total 512
-rw------- 1 root root 10G Jun 24 12:58 test0.img

address@hidden ~]# qemu-system-x86_64 -drive file=gluster://127.0.0.1/vol0/test0.img                                                                                                                                                                                                 
qemu-system-x86_64: -drive file=gluster://127.0.0.1/vol0/test0.img: could not open disk image gluster://127.0.0.1/vol0/test0.img: Operation not supported

I indeed remove all the other parameters of the VM as it doesn't seem relevant as any combination gives the same result.
I also tried adding the drive to a running machine through libvirt with this XML file:

    <disk type='network' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source protocol='gluster' name='vol0/test0.img'>
        <host name='bbox' transport='tcp' />
      </source>
      <target dev='vdb' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>

address@hidden ~]# virsh attach-device test /tmp/gluster_disk.xml                                                                                                                                                                                                                    
error: Failed to attach device from /tmp/gluster_disk.xml
error: operation failed: open disk image file failed

By enabling libvirt debug, it actually gets the "Operation not supported" back from qemu...
I also straced the qemu process without seeing anything relevant to the error.

Did i miss something? I haven't seen any relevant documentation concerning some particular settings to make this work.

Any help appreciated.


Regards,
Olivier