netcats: libvirt Remote Daemon over SSH

For one of my university courses, I need to run a virtual machine with Kali Linux.

Because it is 2018, my laptop is not really fast enough for a VM, I like cloud technology and I love tinkering with stuff, I wanted to use libvirt’s remote support to run the virtual machine on one of my cloud servers.

First, I installed libvirt by apt-get installing libvirt-daemon libvirt-daemon-system qemu-kvm.

Since I already have an SSH connection to the host set up, I chose the SSH transport, but got the following error message from virt-manager:

libvirt virt-manager error message

Unable to connect to libvirt.

The remote host requires a version of netcat/nc which supports the -U option.

I logged into my server and checked if netcat was installed, which it was.

But there are two versions of netcat on Debian Stretch available: netcat-traditional and netcat-openbsd - only the latter one supports the required -U flag, which specifies to use UNIX-domain sockets. (Here is the man page of netcat-traditional, for reference)

You can check which one you have installed with dpkg:

$ dpkg -l netcat-*

After installing netcat-openbsd and removing netcat-traditional, connecting to the remote libvirt daemon over SSH worked just fine.

In the end, I had to recognize that hardware acceleration is not available, as this server is running on a shared host:

# virt-host-validate
QEMU: Checking for hardware virtualization                                 : FAIL (Only emulated CPUs are available, performance will be significantly limited)
QEMU: Checking if device /dev/vhost-net exists                             : PASS
QEMU: Checking if device /dev/net/tun exists                               : PASS
QEMU: Checking for cgroup 'memory' controller support                      : PASS
QEMU: Checking for cgroup 'memory' controller mount-point                  : PASS
QEMU: Checking for cgroup 'cpu' controller support                         : PASS
QEMU: Checking for cgroup 'cpu' controller mount-point                     : PASS
QEMU: Checking for cgroup 'cpuacct' controller support                     : PASS
QEMU: Checking for cgroup 'cpuacct' controller mount-point                 : PASS
QEMU: Checking for cgroup 'cpuset' controller support                      : PASS
QEMU: Checking for cgroup 'cpuset' controller mount-point                  : PASS
QEMU: Checking for cgroup 'devices' controller support                     : PASS
QEMU: Checking for cgroup 'devices' controller mount-point                 : PASS
QEMU: Checking for cgroup 'blkio' controller support                       : PASS
QEMU: Checking for cgroup 'blkio' controller mount-point                   : PASS
QEMU: Checking for device assignment IOMMU support                         : WARN (Unknown if this platform has IOMMU support)
 LXC: Checking for Linux >= 2.6.26                                         : PASS
 LXC: Checking for namespace ipc                                           : PASS
 LXC: Checking for namespace mnt                                           : PASS
 LXC: Checking for namespace pid                                           : PASS
 LXC: Checking for namespace uts                                           : PASS
 LXC: Checking for namespace net                                           : PASS
 LXC: Checking for namespace user                                          : PASS
 LXC: Checking for cgroup 'memory' controller support                      : PASS
 LXC: Checking for cgroup 'memory' controller mount-point                  : PASS
 LXC: Checking for cgroup 'cpu' controller support                         : PASS
 LXC: Checking for cgroup 'cpu' controller mount-point                     : PASS
 LXC: Checking for cgroup 'cpuacct' controller support                     : PASS
 LXC: Checking for cgroup 'cpuacct' controller mount-point                 : PASS
 LXC: Checking for cgroup 'cpuset' controller support                      : PASS
 LXC: Checking for cgroup 'cpuset' controller mount-point                  : PASS
 LXC: Checking for cgroup 'devices' controller support                     : PASS
 LXC: Checking for cgroup 'devices' controller mount-point                 : PASS
 LXC: Checking for cgroup 'blkio' controller support                       : PASS
 LXC: Checking for cgroup 'blkio' controller mount-point                   : PASS

Oh well. At least I learned something about the awesome libvirt Virtualization API today.