Say Hello to the oVirt Engine Virtual Appliance

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One of the things on the list for oVirt 3.5 was the oVirt Virtual Appliance. Huh, what’s that? You might ask. Well, imagine a cloud image with oVirt Engine 3.5 and it’s dependencies pre-installed, and a sane default answer file for ovirt-engine-setup. All of this delivered in an OVA file. The intention is to get you a running oVirt Engine without much hassle.

Furthermore this appliance can be used in conjunction with the Self Hosted Engine feature, and the upcoming oVirt Node Hosted Engine plugin (note the Node within).

Just as a reminder to myself: Hosted Engine is a feature where a VM containing the oVirt Engine instance is managed by itself.

As you can find more informations about the oVirt Hosted Engine and oVirt Node Hosted Engine elsewhere, let me just drop a couple of words on the appliance.

The appliance is based on the Fedora 19 cloud images, with some modifications and oVirt Engine packages pre-installed. An answer file can be used as a starting point for engine-setup.

Quick Guide

Build Download the appliance yourself

# Get the sources
$ git clone git://gerrit.ovirt.org/ovirt-appliance
$ cd ovirt-appliance
$ git submodule update --init
$ cd engine-appliance

# To only build the `.raw` image use:
$ make ovirt-appliance-fedora.raw

# And run the image:
$ qemu-kvm -snapshot -m 4096 -smp 4 -hda ovirt-appliance-fedora.raw

Inside the VM:

  • Wait a bit
  • Finish the initial-setup (set a root password and optionally add a user)

and run:

$ engine-setup --config-append=ovirt-engine-answers

Building the virtual appliance

To build the appliance you need three ingredients:

  • The appliance kickstarts (kept in the ovirt-appliance repo)
  • A Fedora 19 boot.iso (or the netinstall iso)
  • lorax and pykickstart installed

The build process can then be initiated by running:

$ yum install lorax pykickstart
$ git clone git://gerrit.ovirt.org/ovirt-appliance
$ cd ovirt-appliance
$ git submodule update --init
$ cd engine-appliance

# Build the .ova
$ make

# Or: To only build the `.raw` image (without sparsification/sysprep) use:
$ make ovirt-appliance-fedora.raw

The .ova build will actually go through the following steps:

  • Create a kickstart from the provided template
  • Pass the boot iso and kickstart to livemedia-creator (part of lorax)
  • sysprep, resize, sparsify and convert the intermediate image to OVA

The .ova file now contains some metadata and the qcow2 image, to extarct the image run:

$ mkdir out ; cd out
$ tar xf ../ovirt-appliance-fedora.ova

# Run the image:
$ qemu-kvm -snapshot -m 4096 -smp 4 -hda images/*/!(*.meta)

Running the virtual appliance

Once the image is build - an image called ovirt-appliance-fedora.ova should be in your working directory - you can point hosted-engine-setup to it, which will use it for the initial VM. If you want to try the imagine with qemu (or libvirt), just use the .raw image (also available in the current workingdir) and something like:

$ qemu-kvm -snapshot -m 4096 -smp 4 -hda ovirt-appliance-fedora.raw

Once you boot into the image, the initial-setup dialog will pop-up to guide you through some initial steps.

Finishing the ovirt-engine-setup

Once you finished the initial-setup (which should be self describing), login as root and run:

$ engine-setup --config-append=ovirt-engine-answers

Comments on some design decisions

Why Fedora and why 19? Because oVirt Engine runs fine on Fedora 19. Also Fedora provides a nice set of cloud images (kickstarts) from which the oVirt Engine appliance inherits, this eases the maintenance. Fedora 20 is not used because Engine did not support it when the development of the appliance started.

Why not CentOS? We started with Fedora 19, because the cloud images where available, the plan is to either adapt them to CentOS, or look if they’ve also got cloud image kickstarts from which we could inherit.

Why initial-setup? Another reason for using Fedora 19 was, that anaconda could be leveraged to run the inital-setup. The initial-setup is responsible to ask the user some questions (what root password, what timezone, and if an additional user should be created). cloud-init could not be used, because cloud-init requires some kind of management instance at boot time (like oVirt or OpenStack) to get configured. But this isn’t the case with the virtual appliance, because the appliance will only become the Engine.

A FutureFeature could be to add another spoke to the initial-setup where the remaining questions for the engine-setup are asked, that way a user is actually guided through the setup, and does not need to manually trigger the engine-setup after login.

Less maintenance!? In general the ovirt-appliance-fedora.ks inherits from the fedora-spin-kickstarts/fedora-cloud-base.ks file. We also try hard to not diverge to much from the upstream configuration. But some modifications are applied to the final (post-ksflatten) kickstart, to change some defaults which are currently set in the fedora-cloud-base.ks.

In detail we do the following: * Don’t blacklist any package - To prevent missing dependencies * Disable text installation - This does not work with livemedia-creator * Change the partition (rootfs) size to 4GB * Generalize network activation - To be independent of nick names * Ignore missing packages - Because the cloud ks uses Fedora 20 package names * Do not explicitly set the default target * Remove disablement of initial-setup - Because we use it * Remove dummy user game - Not needed because initial-setup is used

Take a look at the Makefile for the exact informations.

Where is the UI? The appliance comes without a desktop environment. There is no hard need for it (some other host with an OS can be used to access Engine’s web-ui) and it keeps the image small.

If you want to add a desktop environment, you are free to do so, by using yum.

Next steps

This is the first shot of this appliance. Let’s see how it turns out. Some integration tests with the oVirt Node Hosted Engine plugin are pending. I expect some more cleanup and fixes, before it’s ready for the oVirt 3.5 TestDays.

Open items include:

  • Heavy testing
  • …

So feel enlighted to try out the ready to use image or build the appliance yourself. Please provide feedback and questions to the users@ovirt.org mailinglist.

::: {#footer} [ June 16th, 2014 11:16am ]{#timestamp} [ovirt]{.tag} [appliance]{.tag} [engine]{.tag} [node]{.tag} [19]{.tag} [libguestfs]{.tag} [libvirt]{.tag} [qemu]{.tag} [lorax]{.tag} [ova]{.tag} [virtual]{.tag} [hosted-engine]{.tag} [fedora]{.tag} :::