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Virt-builder generates VM images in a flash

Greased Lightning

The Linux universe is taking giant steps in the field of virtualization. At first, there was only VMware, and then Xen was very popular for a time. Meanwhile, KVM (Kernel Virtual Machine) has become the dominant hypervisor system; for example, Red Hat's enterprise virtualization solution is based on it. Red Hat seeks to grab some of VMware's market share with its RHEV (Red Hat Enterprise Virtualization) advanced development, but given that Microsoft's Hyper-V has the same ambitions, this could prove to be a lofty goal.

Red Hat puts much energy into developing the Linux kernel, the hypervisor, and the whole infrastructure. An example is libguestfs , which supports access to and working with virtual disk images. It was presented in Linux Magazine by Red Hat developer Richard W.M. Jones [1], who has now added a new tool to the collection. For some time, Jones has been experimenting with Supermin appliances: extremely small images (around 100KB) that boot in seconds. Based on this, he has developed the virt-builder [2] tool, which greatly accelerates the installation of new VM images. Otherwise, this can be a rather lengthy process that includes performing a normal installation of a Linux distribution.

Lightning VMs

With virt-builder, the whole process happens a bit faster; a new VM image is created on the basis of stripped-down templates that include only the most essential components – a Linux kernel, the basic daemons, and systemd. Drawing on more tools from the libguestfs package, virt-builder modifies the template to suit the administrator's needs – for example, setting the root password, configuring the network, and so on.

Virt-builder is provided in the libguestfs packages as of version 1.24, although no current Linux distribution has these packages on

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