On Thu, Dec 24, 2015 at 06:16:09PM +0200, Yaniv Kaul wrote: I believe this _won't_ work as you probably discovered already: virt-customize -a cloud.img --install kernel-core The --install flag runs 'dnf -y install', which means it just checks that kernel-core is installed and stops if it is already installed. (Whereas 'dnf -y install --best' tries to update the package to the "best", ie highest, version). For --update, that was fixed in commit 16e6378a5b4b2 (2015-08-04). But we didn't change the behaviour of --install. Perhaps we should. If you have a particular package that you want to install, an alternative would be something like: virt-customize -a cloud.img --install fedora-repos-rawhide --install https://kojipkgs.fedoraproject.org//packages/kernel/4.4.0/0.rc6.git1.1.fc... Assuming that you choose a package that exists in (guest) repos that are already set up in the image, dnf will go and find any dependencies automatically and update things to the version you requested. Otherwise you could either list all dependencies on the virt-customize command line (gets tedious quite quickly), or drop a repo file into /etc/yum.repos.d/ using the virt-customize --write flag. Or install the correct repos package, which is what '--install fedora-repos-rawhide' is doing above. It helps to look at the code to see the command that gets run when you use the --install (or other) option: https://github.com/libguestfs/libguestfs/blob/master/customize/customize_... To run commands directly under your control, use --run-command. Perhaps this is a better option? virt-customize -a cloud.img --run-command ' dnf -y install --best kernel-core ' If you want everything to be super-controllable by you, including making it work even if the network is down, then put the RPMs required into an ISO and use the --attach + --run-command options. Something like this: genisoimage -o drivers.iso -V DRIVERS ... plus other parameters to make an ISO from your RPMs directory virt-customize -a cloud.img --attach drivers.iso --run-command ' mkdir /tmp/mount mount LABEL=DRIVERS /tmp/mount dnf -y install --best /tmp/mount/path/to/my/drivers/*.rpm ' [I talk about RPMs above, but everything I said applies equally to Debian/Ubuntu + dpkg, or other Linux distros.] Yes, if you need to boot with the driver, then you need to do an offline install of some kind. As you say --firstboot / cloud-init is too late. It's the same problem that virt-v2v has. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top