Ian Wienand 274be6de55 Making element overriding explicit
This is a re-factor of element_dependencies to achieve two things --
centralising override policy and storing path names.

Firstly we want to make the override policy for elements completely
explicit.  Currently, elements that wish to copy parts of other
elements walk ELEMENTS_PATH themselves and look for elements in
IMAGE_ELEMENT.  How they handle duplicate elements can differ, leading
to inconsistent behaviour.

We introduce logic in element-info to find elements in each of the
directories in ELEMENT_PATHS in *reverse* order -- that is to say,
earlier entries in the paths will overwrite later ones.

For example

 ELEMENT_PATHS=foo:bar:baz

will mean that "foo/element" will override "baz/element", since "foo"
is first.  This should be sane to anyone familiar with $PATH.
Documentation is clarified around this point and a test-case is added.

The second thing is that we want to keep the complete path of the
elements we have chosen.  We want the aforementioned elements that
walk the element list to use these canonical paths to pickup files;
this way they don't need to make local decisions about element
overrides, but can simply iterate a list and copy/merge files if they
exist.

A follow-on change (I7092e1845942f249175933d67ab121188f3511fd) will
expose this data in a separate variable that can be parsed by elements
(a further follow-on I0a64b45e9f2cfa28e84b2859d76b065a6c4590f0
modifies the elements to use this information).  Thus this does not
change the status-quo -- elements that are walking ELEMENTS_PATH
themselves and can/will continue doing that.

Change-Id: I2a29861c67de2d25c595cb35d850e92807d26ac6
2016-09-08 10:58:19 +10:00
2014-09-30 16:39:21 -05:00
2012-11-15 16:20:32 +13:00
2015-09-16 13:52:43 +10:00
2015-09-22 09:17:08 +00:00
2016-04-21 13:19:53 +10:00

Image building tools for OpenStack

diskimage-builder is a flexible suite of components for building a wide-range of disk images, filesystem images and ramdisk images for use with OpenStack.

This repository has the core functionality for building such images, both virtual and bare metal. Images are composed using elements; while fundamental elements are provided here, individual projects have the flexibility to customise the image build with their own elements.

For example:

$ DIB_RELEASE=trusty disk-image-create -o ubuntu-trusty.qcow2 vm ubuntu

will create a bootable Ubuntu Trusty based qcow2 image.

diskimage-builder is useful to anyone looking to produce customised images for deployment into clouds. These tools are the components of TripleO that are responsible for building disk images. They are also used extensively to build images for testing OpenStack itself, particularly with nodepool. Platforms supported include Ubuntu, CentOS, RHEL and Fedora.

Full documentation, the source of which is in doc/source/, is published at:

Copyright

Copyright 2012 Hewlett-Packard Development Company, L.P. Copyright (c) 2012 NTT DOCOMO, INC.

All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Description
Image building tools for OpenStack
Readme 58 MiB
Languages
Shell 50.3%
Python 49.5%
Jinja 0.2%