On 29/04/2019 22.01, Michal Privoznik wrote:
> On 4/29/19 1:06 PM, lameventanas(a)gmail.com wrote:
>> I want to run libvirtd as a special user, and allowing users that belong
>> to a special group to connect via qemu+unix:///system (eg: unix socket).
>>
>> I did everything necessary to do so: created a libvirt user and group,
>> added the libvirt user to the kvm group, added my normal user to the
>> libvirt group, and made sure the socket is owned by libvirt:libvirt with
>> permissions set to 770.
>>
>> libvirtd starts successfully, but when I try to connect as the normal
>> user I get this error:
>>
>> bash$ virsh --connect qemu+unix://system
>> error: failed to connect to the hypervisor
>> error: invalid argument: using unix socket and remote server 'system'
is
>> not supported.
>
> This is not valid URI.
>
>
https://libvirt.org/uri.html
>
> You may want to use 'qemu+unix:///system' or simply
'qemu:///system'
> which is the same because libvirt connects via unix socket by default.
Thanks, I missed that.
Now I get this:
$ virsh --connect qemu:///system
error: failed to connect to the hypervisor
error: internal error: unexpected QEMU URI path '/system', try
qemu:///session
But now I see virsh opening the socket, writing, etc.
The server log shows this:
2019-04-29 15:32:07.306+0000: 20863: info : libvirt version: 5.2.0
2019-04-29 15:32:07.306+0000: 20863: info : hostname: koji
2019-04-29 15:32:07.306+0000: 20863: error : virDBusGetSessionBus:169 :
internal error: Unable to get DBus session bus connection: Unable to
autolaunch a dbus-daemon without a $DISPLAY for X11
2019-04-29 15:32:24.534+0000: 20852: error : qemuConnectOpen:1127 :
internal error: unexpected QEMU URI path '/system', try qemu:///session
2019-04-29 15:32:24.534+0000: 20851: error : virNetSocketReadWire:1803 :
End of file while reading data: Input/output error
I also wonder if dbus is important, and if so, how to fix it.
> Anyway, you'll need to run libvirtd privileged, otherwise it'll get
> EPERM when trying to do almost anything.
I'm aware of that, I want to try and see the limitations, and maybe get
around them by using capabilities?
Libvirt has two distinct modes of operation - system mode and session
mode. When uid == 0, libvirtd runs in system mode & offers full
privileges. When uid != 0 it runs in session mode & disables alot of
functionality, or it will simply fail to use it.
It is impossible to run system mode as uid != 0, as it will always
activate session mode in this case.
Regards,
Daniel
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