openATTIC (Posts about kvm)

How to create a vagrant VM from a libvirt vm/image

Kai Wagner — Thu, 11 Jan 2018 10:52:54 GMT

It cost's me some nerves and time to figure out how to create a vagrant image from a libvirt kvm vm and how to modify an existing one. Thanks to pl_rock from stackexchange for the awesome start.

First of all you have to install a new vm as usual. I've installed a new vm with Ubuntu 16.04 LTS. I'm not sure if it's really neccessary but set the root password to "vagrant", just to be sure.
Connect to your VM via ssh or terminal and do the following steps.

Reduce KVM disk size with dd and sparsify

Kai Wagner — Tue, 01 Nov 2016 08:45:38 GMT

You can convert a raw or qcow2 non-sparse image to a sparse image with dd and sparsify. Or you can reduce the size of an existing image again.

Install the libguestfs-tools on your system

apt-get install libguestfs-tools

Now copy your existing image to a new one with dd

dd if=existing_imagefile.raw of=new_imagefile.raw conv=sparse

Afterwards use virt-sparsify to reduce your disk size again (in this example I sparsed and converted the image in just one step)

virt-sparsify new_imagefile.raw --convert qcow2 new_imagefile.qcow2

In my case I converted a block device with 65GB with dd sparse to 40GB raw image and afterwards I used virt-sparsify to reduce the size down to 6.8GB.

KVM guest with acpid installed will not shutdown

Kai Wagner — Tue, 30 Aug 2016 14:17:42 GMT

Yesterday a colleague migrated a physical machine into a kvm vm. Afterwards we wanted to manage the vm within virt-manager.

Acpid was installed, but nothing happend if we tried to shutdown or reboot the vm via acpi requests.

The problem was, that the migrated kvm vm still tought that it is a hardware instead of a vm. Therefore I changed the entry within the acpi events.

Edit /etc/acpi/events/powerbtn to contain action=/sbin/poweroff

As an alternative you could purge and reinstall the acpid package.

apt-get purge acpid

apt-get install acpid

Sometimes it's that easy :-)