Help-Faster-Builds.txt

CLIP builds take some time. A good bit of this time
is due to re-rolling an entire installation image
including re-creating Anaconda's live environment
used during installation. One way to think of it is

1. CLIP builds source packages, then, using mock, it builds binary packages.

2. CLIP, using Pungi and Lorax, creates a full OS install of all the packages
Anaconda needs in the live environment. This part is
a full install of RPMs into the live image environment.
Effectively, it installs a whole OS during this process.

3. The live environment and installation package set is
placed into a directory and packed up into an ISO.

Steps 2 and 3 above can be eliminated in most circumstances.
So, the fast build concept has been introduced that skips
step 2 and reduces the work done in step 3. 

Before we start be aware that fast builds
don't re-create and entire SIO from source,
inclduing an Anaconda modifications. So 
don't use this for production images.

To use fast builds you need one additional
thing compared to normal builds - a "donor
ISO" containing a full Anaconda-based installation
environment. Basically, you need a RHEL installation
ISO or a CLIP ISO.

Then, having that ISO hand, you change our build target
and add a single flag. 

Instead of doing this:
make clip-minimal-inst-iso

you do this:
make clip-minimal-inst-iso-fast DONOR_ISO=foo.iso

This takes a twenty minute build and brings it down
to about four minutes on one of our build systems.

NOTE: as a result of not re-rolling anaconda or
other parts of the ISO, like the bootloader, the
ISO version stored in those components remains the same
meaning what you see when booting and running Anaconda
might not match the version of the packages, kickstart,
etc. This is expected, but might be misleading.

Again, do not use this feature when generating production ISOs.
Enjoy!