We use kvm on ubuntu 10.4 as virtualisation-solution (we have bash-scripted the whole networking, subneting, starting of vms.....
Is there a way to shutdown a kvm-guest without the usage of libvirt/virsh? A bash or python based solution would be great.
we are using kvm/qemu with qcow2-images for our virtual machines.
qcow2 has this nice feature where the image file only allocates the actually needed space by the virtual-machine. but how do i shrink back the image file, if the virtual machine's allocated space gets smaller?
example:
1.) i create a new image with qcow2 format, size 100GB
2.) i use this image to install ubuntu. installation needs about 10 gb, the image-file grows up to about 10GB. nothing unexpected so far.
3.) i fill up the image with about 40 GB of additional data. the image-file grows up to 50GB. i am ok with that :-)
4.) this is where it gets strange: i delete all of the 40GB data on the image, but the image-size still eats up 50GB.
question: how do i free up that 40GB of data and shrink the image to the only needed 10 GB?
thanks in advance, berni
I run several VM's on KVM/ubuntu, which all get started with the -snapshot parameter (the VM's only compute several things which can be destroyed after reboot).
Out of the docs I've read, the changes are not written back to the image, but stored in temp-files and these are deleted after shutdown.
Now, I wonder where on the filesystem these "temp-files" are stored?
is there a way to just execute a command (or script) on a user (ssh) login and then exit? some kind of replacing the default shell with a custom script.
i want a user only be able to restart a service, but not to have regular shell-access
thanks