[SOLVED] Can't start the new (14) Whonix VMs - libvirtError: unsupported configuration: Block I/O tuning is not available on this host

SDi · August 15, 2018, 10:47am

I was using Whonix on KVM until upgrade to 14. I was all ok. Now I made fresh install according to wiki. And I get the problem with VMs start (both Gate and Workstation). Here’s error:

Error starting domain: unsupported configuration: Block I/O tuning is not available on this host
Traceback (most recent call last):
File “/usr/share/virt-manager/virtManager/asyncjob.py”, line 89, in cb_wrapper
callback(asyncjob, *args, **kwargs)
File “/usr/share/virt-manager/virtManager/asyncjob.py”, line 125, in tmpcb
callback(*args, **kwargs)
File “/usr/share/virt-manager/virtManager/libvirtobject.py”, line 82, in newfn
ret = fn(self, *args, **kwargs)
File “/usr/share/virt-manager/virtManager/domain.py”, line 1508, in startup
self._backend.create()
File “/usr/lib64/python2.7/site-packages/libvirt.py”, line 1069, in create
if ret == -1: raise libvirtError (‘virDomainCreate() failed’, dom=self)
libvirtError: unsupported configuration: Block I/O tuning is not available on this host

Maybe new 14 Whonix requires some special features in the kernel of the host? What option should I enable in it?
Or maybe I have compiled qemu/libvirt without some needed flags to run new Whonix?

ps Gentoo Linux, 4.14.61-gentoo-gnu, x86_64.

HulaHoop · August 14, 2018, 2:09pm

Please upgrade your libvirt to support this feature. It was added to mitigate DoS by malicious guests who might attempt starving the host’s resources.

SDi · August 14, 2018, 2:31pm

Now I have libvirt-4.3
What libvirt version I should upgrade to?
4.4? 4.5?

HulaHoop · August 14, 2018, 5:29pm

Libvirt 3.0 on Debian here so that’s not it. Searching your error hints that qemuCgroupControllerActive may not be active on your system for some reason. So you might want to update that instead.

github.com

wiedi/libvirt/blob/master/src/qemu/qemu_cgroup.c

/*
 * qemu_cgroup.c: QEMU cgroup management
 *
 * Copyright (C) 2006-2012 Red Hat, Inc.
 * Copyright (C) 2006 Daniel P. Berrange
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library;  If not, see
 * <http://www.gnu.org/licenses/>.
 *

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SDi · August 14, 2018, 7:09pm

Thanks for hint. I have enabled CONFIG_BLK_CGROUP in the kernel and now the error is:

Error starting domain: Unable to write to '/sys/fs/cgroup/blkio/machine/qemu-2-Whonix-Gateway.libvirt-qemu/blkio.weight': No such file or directory
    Traceback (most recent call last):
      File "/usr/share/virt-manager/virtManager/asyncjob.py", line 89, in cb_wrapper
        callback(asyncjob, *args, **kwargs)
      File "/usr/share/virt-manager/virtManager/asyncjob.py", line 125, in tmpcb
        callback(*args, **kwargs)
      File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 82, in newfn
        ret = fn(self, *args, **kwargs)
      File "/usr/share/virt-manager/virtManager/domain.py", line 1508, in startup
        self._backend.create()
      File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1069, in create
        if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
    libvirtError: Unable to write to '/sys/fs/cgroup/blkio/machine/qemu-2-Whonix-Gateway.libvirt-qemu/blkio.weight': No such file or directory

SDi · August 14, 2018, 8:11pm

It also needs CONFIG_CFQ_GROUP_IOSCHED and CONFIG_BLK_DEV_THROTTLING
Now, it starts.

HulaHoop · August 15, 2018, 5:23pm

Good. I used to run into mysterious usecase breakage with custom kernel compilation too. Now I just run the distro default and get on with life.

ani44a · March 14, 2019, 3:01am

i have same error
Can you please explain for Linux newbie how to do fix.

SDi · March 15, 2019, 2:32pm

Hello, ani44a
If you have the same error, that’s your kernel has the options mentioned above disabled.
Checkout documentation for your Linux Distribution on how to configure and recompile kernel.
You must have
CONFIG_BLK_CGROUP=y
CONFIG_CFQ_GROUP_IOSCHED=y
CONFIG_BLK_DEV_THROTTLING=y
In the “make menuconfig” you can press / button to find where these options are.