Before you can use minimega, you must build disk images or RAM disks for your
VMs. The minimega distribution includes
vmbetter, which can build several
minimal RAM disks (see
the vmbetter tutorial for more information).
These work well for generic experiments but sometimes, you need more than a
minimal install. This article describes the process to build a VM disk from an
First, you must obtain an install CD as an ISO image. This can be downloaded from the web or provided by a vendor.
In order to perform the install, we create a new qcow and launch a VM with it and the cdrom:
disk create qcow2 ubuntu.qcow2 20G vm config disk ubuntu.qcow2 vm config cdrom ubuntu.iso vm config snapshot false vm launch kvm ubuntu vm start all
Importantly, we set
snapshot=false so that any changes we make to the disk
persist. Without this flag, all the changes would disappear when we killed the
Some installers make use the Internet to pull more recent packages or software. See this article for more information.
The VM should now be running and the installer will be waiting for user input.
miniweb and click through the installer using the web interface.
Once the VM is installed, you may make additional changes to the filesystem in order to make persistent changes. This could mean installing additional software or configurations.
Typically, we add
miniccc to our VM images to facilitate experiment control.
First, we must load the binary onto the VM. This can be done in a number of
different ways including over the network (if the VM is launched with an
interface) or via the
miniccc is on the VM, we must configure it to start automatically.
There are several examples of integrating miniccc into vmbetter-built VMs in
the repo (see
To start miniccc automatically with systemd, add the following to
[Unit] Description=miniccc [Service] ExecStart=/miniccc -v=false -serial /dev/virtio-ports/cc -logfile /var/log/miniccc.log [Install] WantedBy=multi-user.target
You may need to adjust the ExecStart command if you copied miniccc elsewhere. And then enable the service:
systemctl enable miniccc.service
This will start miniccc whenever the VM starts. If you are adding to a VM with snapshot=false, you should now shutdown the VM and save the disk image.
The built-in Task Scheduler on Windows can be configured to run
To make the image smaller, you may wish to remove any cached files (e.g. run
Before finalizing a Windows VM, it is a good idea to use Sysprep to generalize the VM. This removes computer-specific information so that when you launch multiple VMs from the same image, they each have a different identifier.
Finally, shutdown the VM from within the VM using the standard shutdown
mechanism. Wait for the VM to fully shutdown to ensure that the filesystem is
in a consistent state. minimega will update the VM state to
quit when the VM
has fully powered off. You may now call
vm flush to remove the VM.
The image should now be ready to use:
vm config disk ubuntu.qcow2 vm launch kvm ubuntu[0-3] vm start all
Note that further changes can be made by launching the VM with