================================ Tools to automate image creation ================================ There are several tools that are designed to automate image creation. .. contents:: :depth: 3 OpenStack tools --------------- Diskimage-builder ~~~~~~~~~~~~~~~~~ `Diskimage-builder `_ is an automated disk image creation tool that supports a variety of distributions and architectures. Diskimage-builder (DIB) can build images for Fedora, Red Hat Enterprise Linux, Ubuntu, Debian, CentOS, and openSUSE. DIB is organized in a series of elements that build on top of each other to create specific images. To build an image, call the following script: .. code-block:: console # disk-image-create ubuntu vm This example creates a generic, bootable Ubuntu image of the latest release. Further customization could be accomplished by setting environment variables or adding elements to the command-line: .. code-block:: console # disk-image-create -a armhf ubuntu vm This example creates the image as before, but for arm architecture. More elements are available in the `git source directory `_ and documented in the `diskimage-builder elements documentation `_. External tools -------------- image-bootstrap ~~~~~~~~~~~~~~~ `image-bootstrap `_ is a command line tool that generates bootable virtual machine images with support for Arch, Debian, Gentoo and Ubuntu, and is prepared for use with OpenStack. KIWI ~~~~ The `KIWI appliance builder `_ provides an operating system image builder for various Linux supported hardware platforms as well as for virtualization and cloud systems. It allows building of images based on openSUSE, SUSE Linux Enterprise, and Red Hat Enterprise Linux. The `KIWI NG Documentation `_ explains how to use it. openstack-debian-images ~~~~~~~~~~~~~~~~~~~~~~~ `openstack-debian-images `_ is the tool Debian uses to create its official OpenStack image. It is made of a single very simple shell script that is easy to understand and modify. It supports Grub and Syslinux, BIOS or EFI, amd64 and arm64 arch. openstack-debian-images can also be used to create a bootable image directly on a hard disk, instead of using the Debian installer. To build an image, type this: .. code-block:: console # build-openstack-debian-image --release stretch More parameters can be added to further customize the image: .. code-block:: console # build-openstack-debian-image --release stretch \ --hook-script /root/my-hook-script.sh \ --debootstrap-url http://ftp.fr.debian.org/debian \ --sources.list-mirror http://ftp.fr.debian.org/debian \ --login myusername \ --extra-packages vim,emacs The file ``/root/my-hook-script.sh`` will recieve 2 environment variable: ``BODI_CHROOT_PATH`` path where the image is mounted, and ``BODI_RELEASE`` which is the name of the Debian release that is being bootstraped. Here's an example for customizing the motd: .. code-block:: console # #!/bin/sh set -e echo "My message" >${BODI_CHROOT_PATH}/etc/motd This hook script will conveniently be called at the correct moment of the build process, when everything is installed, but before unmounting the partition. Oz ~~ `Oz `_ is a command-line tool that automates the process of creating a virtual machine image file. Oz is a Python app that interacts with KVM to step through the process of installing a virtual machine. It uses a predefined set of kickstart (Red Hat-based systems) and preseed files (Debian-based systems) for operating systems that it supports, and it can also be used to create Microsoft Windows images. A full treatment of Oz is beyond the scope of this document, but we will provide an example. You can find additional examples of Oz template files on GitHub at `rcbops/oz-image-build/tree/master/templates `_. Here's how you would create a CentOS 6.4 image with Oz. Create a template file called ``centos64.tdl`` with the following contents. The only entry you will need to change is the ```` contents. .. code-block:: xml This Oz template specifies where to download the Centos 6.4 install ISO. Oz will use the version information to identify which kickstart file to use. In this case, it will be `RHEL6.auto `_. It adds EPEL as a repository and install the ``epel-release``, ``cloud-utils``, and ``cloud-init`` packages, as specified in the ``packages`` section of the file. After Oz completes the initial OS install using the kickstart file, it customizes the image with an update. It also removes any reference to the eth0 device that libvirt creates while Oz does the customizing, as specified in the ``command`` section of the XML file. To run this: .. code-block:: console # oz-install -d3 -u centos64.tdl -x centos64-libvirt.xml * The ``-d3`` flag tells Oz to show status information as it runs. * The ``-u`` tells Oz to do the customization (install extra packages, run the commands) once it does the initial install. * The ``-x`` flag tells Oz what filename to use to write out a libvirt XML file (otherwise it will default to something like ``centos64Apr_03_2013-12:39:42``). If you leave out the ``-u`` flag, or you want to edit the file to do additional customizations, you can use the :command:`oz-customize` command, using the libvirt XML file that :command:`oz-install` creates. For example: .. code-block:: console # oz-customize -d3 centos64.tdl centos64-libvirt.xml Oz will invoke libvirt to boot the image inside of KVM, then Oz will ssh into the instance and perform the customizations. Packer ~~~~~~ `Packer `_ is a tool for creating machine images for multiple platforms from a single source configuration. virt-builder ~~~~~~~~~~~~ `Virt-builder `_ is a tool for quickly building new virtual machines. You can build a variety of VMs for local or cloud use, usually within a few minutes or less. Virt-builder also has many ways to customize these VMs. Everything is run from the command line and nothing requires root privileges, so automation and scripting is simple. To build an image, call the following script: .. code-block:: console # virt-builder fedora-23 -o image.qcow2 --format qcow2 \ --update --selinux-relabel --size 20G To list the operating systems available to install: .. code-block:: console $ virt-builder --list To import it into libvirt with :command:`virsh`: .. code-block:: console # virt-install --name fedora --ram 2048 \ --disk path=image.qcow2,format=qcow2 --import windows-openstack-imaging-tools ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `windows-openstack-imaging-tools `_ is a PowerShell module that automates the Windows image creation for OpenStack and supports building VHDX, QCOW2, RAW and VMDK image types. For easier installation, the tool is published as a PowerShellGallery module `WindowsImageBuilder `_. Windows image build example: .. code-block:: powershell # Install and import WindowsImageBuilder module from PowerShellGallery Install-Module WindowsImageBuilder -Force Import-Module WindowsImageBuilder New-WindowsImageConfig -ConfigFilePath ".\windows-image-config.ini" # Update the configuration file to fit your specific use case # Extensive information for all the configuration can be found here: # https://github.com/cloudbase/windows-openstack-imaging-tools/blob/master/Config.psm1#L21 # Generate the Windows image New-WindowsOnlineImage -ConfigFilePath ".\windows-image-config.ini" Requirements: * A Windows host, with Hyper-V virtualization enabled, PowerShell >=v4 support and Windows Assessment and Deployment Kit (ADK). * A Windows installation ISO or DVD. * Windows compatible drivers, if required by the target environment. For example, `VirtIO `_, network card, or storage adapter drivers. * Git environment.