libvirt users - Feb 2016 - Running Commands on a Domain

I have added a user to the libvirt group on my CentOS 7.2 server and 
that user can successfully access the Virtual Machine Manager without 
authenticating as expected. This allows the user to perform all 
functions in the VMS as if they were root. This is acceptable as this is 
a private server with no outside access so security is not a real issue.

But when that same user tries to perform functions with virsh or using a 
Python script that uses the libvirt module, the connection is just 
read-only.

Why are the permissions different for these environments and what must I 
do to give the user r/w access in virsh or the Python script?

David Ashley

On Tue, Jan 19, 2016 at 02:36:02PM -0600, David Ashley
wrote:
>I have added a user to the libvirt group on my CentOS 7.2 server and
>that user can successfully access the Virtual Machine Manager without
>authenticating as expected. This allows the user to perform all
>functions in the VMS as if they were root. This is acceptable as this is
>a private server with no outside access so security is not a real issue.
>
>But when that same user tries to perform functions with virsh or using a
>Python script that uses the libvirt module, the connection is just
>read-only.
>
>Why are the permissions different for these environments and what must I
>do to give the user r/w access in virsh or the Python script?
>
I'm guessing (really just guessing), that virt-manager tries connecting
to qemu:///system, but you are connecting to your default uri which is
qemu:///session for non-root users.  You can try connecting to
qemu:///system and that should work.  If you don't want to modify the
code, you can change the default uri in ~/.config/libvirt/libvirt.conf
or in environment variable LIBVIRT_DEFAULT_URI (hand-typed, please
re-check).

Martin
>David Ashley
>
>_______________________________________________
>libvirt-users mailing list
>libvirt-users@redhat.com
>https://www.redhat.com/mailman/listinfo/libvirt-users

On 01/20/2016 04:47 AM, Martin Kletzander wrote:
> On Tue, Jan 19, 2016 at 02:36:02PM -0600, David Ashley wrote:
>> I have added a user to the libvirt group on my CentOS 7.2 server and
>> that user can successfully access the Virtual Machine Manager without
>> authenticating as expected. This allows the user to perform all
>> functions in the VMS as if they were root. This is acceptable as this
is
>> a private server with no outside access so security is not a real
issue.
>>
>> But when that same user tries to perform functions with virsh or using
a
>> Python script that uses the libvirt module, the connection is just
>> read-only.
>>
>> Why are the permissions different for these environments and what must
I
>> do to give the user r/w access in virsh or the Python script?
>>
>
> I'm guessing (really just guessing), that virt-manager tries connecting
> to qemu:///system, but you are connecting to your default uri which is
> qemu:///session for non-root users.  You can try connecting to
> qemu:///system and that should work.  If you don't want to modify the
> code, you can change the default uri in ~/.config/libvirt/libvirt.conf
> or in environment variable LIBVIRT_DEFAULT_URI (hand-typed, please
> re-check).
>
> Martin
>
>> David Ashley
>>
>> _______________________________________________
>> libvirt-users mailing list
>> libvirt-users@redhat.com
>> https://www.redhat.com/mailman/listinfo/libvirt-users
Thanks, that was the problem. Connecting with qemu:///system works.

David Ashley

All -

I just published a new blog that provides a solution for running 
commands on multiple domains. This will enable you to perform the same 
or different commands on multiple domains using automation. The solution 
uses Python and its libvirt module. The blog is located at 
http://www.holmes4.com/wda/blogs/index.html.

I hope to present more of these examples of how to use the libvirt 
interface to perform meaningful tasks in the future.

W. David Ashley