[libvirt-users] Unable to create raw volume on netfs storage (Operation not permitted)

[Benjamin Weik]

Hello,

we are trying to create a new setup with a centralized storage server. Currently we are running multiple "All-in-One" hosts using raw volumes stored on the local disk of the server.

I tried it first with samba but it did not work so currently I have configured it as NFS.

This is my current setup:

For Storage:
OS: Ubuntu 16.04 beta (to match vHost version),
IP: 123.123.123.2
NFS: v1.2.8
Samba: v4.3.3

For vHost:
OS: Ubuntu 16.04 beta (as the Package in Ubuntu 14.04 has still a bug that prevents mounting of samba shares)
IP: 123.123.123.3
Libvirt: v2.21
Qemu: 2.5

Both are simply connected via switched network for testing.

So on the Storage server I created a user and a group called vstorage (uid:1000,gid:500)
Then created a folder /pool owned by this user, permission 777
And exported it via nfs in /etc/exports:

/pool   123.123.123.3(rw,async,no_subtree_check,all_squash,anonuid=1000,anongid=500)


On the vHost I defined the pool via XML:

<pool type='netfs'>
  <name>pool</name>
 <source>
    <host name='123.123.123.2'/>
    <dir path='pool'/>
    <format type='nfs'/>
  </source>
  <target>
    <path>/var/lib/virt/images</path>
  </target>
</pool>


When I try to define a volume in the pool, it will always fail if raw format (default) is used.

virsh vol-create-as --pool pool --name test --capacity 512M
error: Failed to create vol test
error: Failed to create file '/var/lib/virt/images/test': Operation not permitted

In /var/log/syslog I can find the following
libvirtd[889]: cannot chown '/var/lib/virt/images/test' to (0, 0): Operation not permitted
libvirtd[889]: Failed to create file '/var/lib/virt/images/test': Operation not permitted

When I try it with a different format, like qcow2 it is working fine:

virsh vol-create-as --pool pool --name test --capacity 512M --format qcow2
Vol test created

I am unable to find the reason for this problem, it also took me quite a while find out that this is a format issue as the error message is actually not really helpful.

I found a small guide on setting up KVM from IBM and they are using NFS with raw images, so I'm not sure where the error is
https://www.ibm.com/developerworks/library/l-using-kvm/

Maybe someone could shed some light on this? The same error message happens btw. with Samba.

Best regards,

Benjamin Weik
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20160210/55011498/attachment.htm>