OZ(part of the Aeolus project) is a neat tool by Chris Lalancette, to create JEOS(just enough operating system) guests with minimal input. Where minimal input include things like: name of the guest ; OS details like – version, arch, url for the OS tree(or ISO), root-passwd. All of these attributes can be defined in a simple XML type file called TDL(template definition language). Read on for details.
Under the hood, OZ uses all the existing Virtualization infrastructure components like kvm/qemu, libvirt, libguestfs.
Ok, OZ workflow goes like this:
1/ Firstly, ensure to have all the Fedora Virtualization packages.(if not already present)
$ yum groupinstall Virtualization
2/ Enable packet forwarding on the host machine. (ensure this).
$ echo 1 > /proc/sys/net/ipv4/ip_forward
3/ Prepare a simple TDL(template definition language)
(Don’t forget to replace the ‘url’ with a working Fedora install tree. Or ISO could also be used as install type. Refer to the ‘References’ section at the bottom)
$ cat fedora_15_x86_64.tdl <template> <name>zeus-f15</name> <os> <name>Fedora</name> <version>15</version> <arch>x86_64</arch> <install type='url'> <url>http://foo.bar.com/fedora/linux/releases/15/Fedora/x86_64/os/</url> </install> <rootpw>testpwd</rootpw> </os> <description>Fedora 15</description> </template>
4/ Now, create the guest using the oz-install tool.(takes roughly 8-9 mins.)
$ /usr/bin/oz-install -d 4 fedora_15_x86_64.tdl 2>&1 | tee f15.out
End of successful ‘oz-install’ output should look like this:
. . . INFO:oz.Guest.FedoraGuest:Cleaning up after install DEBUG:oz.Guest.FedoraGuest:Removing modified ISO Libvirt XML was written to zeus-f15Aug_08_2011-16:16:08
Note: zeus-f15Aug_08_2011-16:16:08 is the xml definition file for the guest just created.
A successful run of oz-install looks like this on the stdout — http://kashyapc.fedorapeople.org/virt/oz/stdout-oz-install.txt
5/ Define the guest with the above XML.
$ virsh define zeus-f15Aug_08_2011-16:16:08 Domain zeus-f15 defined from zeus-f15Aug_08_2011-16:16:08 $ virsh start zeus-f5 $ virsh list --all Id Name State ---------------------------------- 1 zeus-f15 running
I’ve composed most of this into a quick shell script here – http://kashyapc.fedorapeople.org/virt/oz/oz-jeos.bash
References:
- oz project page — http://aeolusproject.org/oz.html.
- More customizations can be done. All the supported attributes for TDL file can be found in the OZ git repo — https://github.com/clalancette/oz/blob/master/docs/tdl.rng
Kashyap Chamarthy 