[one-users] Opennebula 3.0 RC1 and persistent images in KVM VMs

[Alberto Picón Couselo]

Hi all,

I finally executed KVM VM's with persistent disks in OpenNebula.

I made the following changes in /etc/libvirt/qemu.conf

# The user ID for QEMU processes run by the system instance
user = "oneadmin"

# The group ID for QEMU processes run by the system instance
group = "oneadmin"

# Whether libvirt should dynamically change file ownership
# to match the configured user/group above. Defaults to 1.
# Set to 0 to disable file ownership changes.
dynamic_ownership = 1

Oneadmin and libvirt-qemu user and group membership are as follows in 
KVM worker node:

~# groups oneadmin
oneadmin : oneadmin kvm libvirt
~# groups libvirt-qemu
libvirt-qemu : kvm oneadmin

I changed KVM /dev/kvm group from kvm to oneadmin:

~# chgrp oneadmin /dev/kvm
~# ls -la /dev/kvm
crw-rw---- 1 root oneadmin 10, 232 sep 16 20:35 /dev/kvm

I will need to change group permissions of /dev/kvm to oneadmin in 
rc.local because reloading qemu-kvm resets /dev/kvm to kvm group. Do you 
know any other way to set up group of /dev/kvm?

Thank you very much everybody for your help and support!

Best Regards,
Alberto Picón

El 26/09/2011 22:45, Ruben S. Montero escribió:
> Hi
>
> You may  try to disable dynamic ownership in qemu.conf, as:
> ...
> user = "root"
> group = "root"
>
> dynamic_ownership = 0
> ...
>
> Cheers
>
> Ruben
> On Mon, Sep 26, 2011 at 9:52 PM, Alberto Picón Couselo 
> <alpicon1 at gmail.com <mailto:alpicon1 at gmail.com>> wrote:
>
>     Hi, Fabian.
>
>     We have tested root read and write access to NFS mount in KVM
>     worker node and it works correctly. As you stated, when we create
>     a persistent image, Opennebula creates a link to the registered
>     image in /var/lib/{VID}/image. We are using FreeNAS 8.0 Final
>     Release for shared storage and it implements NFSv3.
>
>     When a new instance is deployed using a persistent image, the
>     image changes a quarter of a second to libvirt-bin:kvm file
>     permissions, instance fails to boot with "permission denied" error
>     and persistent image in repository changes its file permissions to
>     root user and root group.
>
>     When we use a non persistent image, KVM instance boots correctly
>     cloning the registered image to /var/lib/{VID}/image/disk.0, and
>     it has libvirt-bin:kvm file permissions during RUNNING state.
>
>     Please, any clue regarding this issue would be really appreciated.
>
>     Best Regards,
>     Alberto Picón
>
>     El 26/09/2011 13:50, Fabian Wenk escribió:
>
>         Hello Alberto
>
>         On 25.09.2011 00 <tel:25.09.2011%2000>:27, Alberto Picón
>         Couselo wrote:
>
>             We have some a problems using persistent KVM images in
>             Opennebula 3.0 RC1.
>
>             Our configuration is as follows:
>
>             Opennebula Front-End Ubuntu LTS 10.04
>             KVM worker node Debian Queeze 6.0.2
>             NAS for NFS Shared storage
>
>
>             Sat Sep 24 23:49:08 2011 [VMM][I]: Command execution fail:
>             'if [ -x
>             "/var/lib/one/remotes/vmm/kvm/deploy" ]; then
>             /var/lib/one/remotes/vmm/kvm/deploy
>             /var/lib/one/212/images/deployment.0
>             tc-kvm-hv02 212 tc-kvm-hv02; else                        
>                  exit 42; fi'
>             Sat Sep 24 23:49:08 2011 [VMM][I]: error: Failed to create
>             domain from
>             /var/lib/one/212/images/deployment.0
>             Sat Sep 24 23:49:08 2011 [VMM][I]: error: internal error
>             process exited
>             while connecting to monitor: qemu: could not open disk image
>             /var/lib/one/212/images/disk.0: Permission denied
>
>
>             Please, can you give us any clue regarding this issue?.
>             Persistent mode
>             for KVM VMs is essential for us...
>
>
>         Is root allowed to read/write in the NFS mounted images
>         folder? Check the options in /etc/exports on the NFS server.
>         Eventually you also need to force the client (cluster node) to
>         mount it using NFSv3 (instead of NFSv4).
>
>         With persistent images, the images stays in the images folder
>         and is only linked from the <vm_id>/images/ folder. KVM does
>         run with root privileges.
>
>
>         bye
>         Fabian
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>
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>
>
>
> -- 
> Dr. Ruben Santiago Montero
> Associate Professor (Profesor Titular), Complutense University of Madrid
>
> URL: http://dsa-research.org/doku.php?id=people:ruben
> Weblog: http://blog.dsa-research.org/?author=7
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