diskimage-builder/diskimage_builder/elements/iso/README.rst
Ian Wienand 97c01e48ed Move elements & lib relative to diskimage_builder package
Currently we have all our elements and library files in a top-level
directory and install them into
<root>/share/diskimage-builder/[elements|lib] (where root is either /
or the root of a virtualenv).

The problem with this is that editable/development installs (pip -e)
do *not* install data_files.  Thus we have no canonical location to
look for elements -- leading to the various odd things we do such as a
whole bunch of guessing at the top of disk-image-create and having a
special test-loader in tests/test_elements.py so we can run python
unit tests on those elements that have it.

data_files is really the wrong thing to use for what are essentially
assets of the program.  data_files install works well for things like
config-files, init.d files or dropping documentation files.

By moving the elements under the diskimage_builder package, we always
know where they are relative to where we import from.  In fact,
pkg_resources has an api for this which we wrap in the new
diskimage_builder/paths.py helper [1].

We use this helper to find the correct path in the couple of places we
need to find the base-elements dir, and for the paths to import the
library shell functions.

Elements such as svc-map and pkg-map include python unit-tests, which
we do not need tests/test_elements.py to special-case load any more.
They just get found automatically by the normal subunit loader.

I have a follow-on change (I69ca3d26fede0506a6353c077c69f735c8d84d28)
to move disk-image-create to a regular python entry-point.

Unfortunately, this has to move to work with setuptools.  You'd think
a symlink under diskimage_builder/[elements|lib] would work, but it
doesn't.

[1] this API handles stuff like getting files out of .zip archive
modules, which we don't do.  Essentially for us it's returning
__file__.

Change-Id: I5e3e3c97f385b1a4ff2031a161a55b231895df5b
2016-11-01 17:27:41 -07:00

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ReStructuredText

===
iso
===
Generates a bootable ISO image from the kernel/ramdisk generated by the
elements ``baremetal``, ``ironic-agent`` or ``ramdisk``. It uses isolinux to boot on BIOS
machines and grub to boot on EFI machines.
This element has been tested on the following distro(s):
* ubuntu
* fedora
* debian
**NOTE**: For other distros, please make sure the ``isolinux.bin`` file
exists at ``/usr/lib/syslinux/isolinux.bin``.
baremetal element
-----------------
When used with ``baremetal`` element, this generates a bootable ISO image
named ``<image-name>-boot.iso`` booting the generated kernel and ramdisk.
It also automatically appends kernel command-line argument
'root=UUID=<uuid-of-the-root-partition>'. Any more kernel command-line
arguments required may be provided by specifying them in
``DIB_BOOT_ISO_KERNEL_CMDLINE_ARGS``.
**NOTE**: It uses pre-built efiboot.img by default to work for UEFI machines.
This is because of a bug in latest version of grub[1]. The user may choose
to avoid using pre-built binary and build efiboot.img on their own machine
by setting the environment variable DIB\_UEFI\_ISO\_BUILD\_EFIBOOT to 1 (this
might work only on certain versions of grub). The current efiboot.img was
generated by the method build\_efiboot\_img() in 100-build-iso on
Ubuntu 13.10 with grub 2.00-19ubuntu2.1.
ramdisk element
---------------
When used with ``ramdisk`` element, this generates a bootable ISO image
named ``<image-name>.iso`` booting the generated kernel and ramdisk. It also
automatically appends kernel command-line argument 'boot\_method=vmedia'
which is required for Ironic drivers ``iscsi_ilo``.
ironic-agent element
--------------------
When used with ``ironic-agent`` element, this generates a bootable ISO image named ``<image-name>.iso`` which boots the agent kernel and agent ramdisk.
**REFERENCES**
[1] https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1378658