Trivial management of 64 bit virtual machines with qemu.
Table of contents
- Table of contents
- What this script will do
- Setup information and usage
- VNC options
- Interesting applications
What this script will do
It can handle:
- Virtual hard disk creation, backup and deletion.
- Basic network management: two ports are exposed to the host machine (but you can add as many as you want). One of these two ports is SSH (so admin gets simpler).
- Connection via SSH.
- Shared directory between host and guest.
- Last, but not least, running the virtual machine with a combination of the previous options.
Setup information and usage
You need a 64 bit machine with virtualization technology and more than 4 GB of RAM.
configvmrcbased on your needs. Variables are self-explanatory and I have kept mine as an example.
Install the following dependencies
Create a new VHD and complete the OS installation:
$ ./qvm -c $ ./qvm -i
Optionally enable the SSH daemon on the guest machine.
Optionally create a new backup VHD:
$ ./qvm -b
Now you can run the virtual machine either using the original or the backup VHD. By deault if you run
./qvmthe virtual machine will run in graphics mode using the backup hard disk.
Optionally add the following in the gues machine's
/etc/fstab, to enable the shared directory automatically (no mount commands of any sort).
host_share /home/vm/shared 9p noauto,x-systemd.automount,trans=virtio,version=9p2000.L 0 0
You can also access the virtual machine through SSH:
$ ./qvm -a
or, if you are working on another computer,
$ ./qvm --attach-remote
The VNC options in this script allow you to connect to a remote instance of
QEMU. This is particularly useful, for example, if your local machine
processor does not support virtualization. The only thing to do is to make
the server's port (
5900) reachable from the clients.
You must then run QVM with one of the VNC options on the server side.
On the client side you must simply edit the
host_username variables in the configuration file.
For example, on the server side we could install the virtual machine remotely like this:
$ ./qvm --install-vnc
And on the client side:
$ ./qvm -r
At this point you should see your virtual machine running in a TigerVNC window.
Note: the VNC traffic goes through SSH TCP forwarding, so it is encrypted.
Virtual machine hard disk over a network protocol
If you happen to use a form of network filesystem, such as GlusterFS, you can keep the machine hard disk off the host and put it on another computer. There might be a some form of lag depending on the hardware, protocol and network connections.
An example with GlusterFS might be:
This will work provided that you install the QEMU GlusterFS block module package (if it's not already present in the QEMU package itself).
You should consult the QEMU's manual to learn about all possible compatible network filesystems.
Automatical remote startup
To automatically start the virtual machine from a non-host computer you can
automatical_remote_startup.sh script. Make sure that both the local
non-host and the remote host computer have a copy of the QVM repository with
the variables correctly set in the
This script will start the virtual machine if on the host computer no other
virtual machine is running. You can use either the VNC or the headless
connection. Both of them require that SSH is configured correctly on the
computers: the host must be reachable from the client via SSH. This can be verified by using the
Once you have checked that everyting works, you can add a command alias in
your shell configuration file (e.g:
~/.bashrc), something like:
Usage: qvm [OPTION] Trivial management of 64 bit virtual machines with qemu. Options: -a, --attach connect to SSH locally --attach-remote connect to SSH remotely -b, --backup backup vhd -c, --create create new vhd -d, --delete delete vhd backup --delete-orig delete original vhd -h, --help print this help -i, --install install img on vhd --install-vnc install img on vhd via vnc -n, --run-nox run vm without opening a graphical window (useful for background jobs like SSH) --run-nox-orig run-orig and run-nox combined -s, --mkdir-shared create shared directory -r, --remote connect to a vnc instance via ssh -x, --run run vm --run-vnc run vm with vnc --run-orig run from original vhd --run-orig-vnc run from original vhd with vnc Only a single option is accepted. By default, the backup vhd is run. CC0 Written in 2016 by Franco Masotti/frnmst <email@example.com>
Usage: automatical_remote_startup.sh [OPTION] Start QEMU on a remote host computer and connect to it Options: -d, --default start the vm in headless mode and connect to it with SSH -h, --help print this help -u, --use-vnc start the vm in VNC mode and connect to it with the VNC client Only a single option is accepted. By default, a headless connection will be initialized. Preconditions for this to work is to setup SSH correctly on both computers. CC0 Written in 2018 by Franco Masotti/frnmst <firstname.lastname@example.org>