I'm one of the Anaconda authors/maintainers. I could go into way too much detail about how the installer boots, but I'll try to be brief.
(Note that this only applies to RHEL/CentOS 6.x or Fedora 14 and earlier; the installer was almost completely rewritten between Fedora 15, 16, and 17, so things are very different now.)
- How does Anaconda get called?
- What is the role of the images/install.img file ? (Who calls/mount it?)
initrd.img on the install media is what we call the stage1 image. It contains a program called
loader, whose only job is to find and load
install.img is the stage2 image. This is where Anaconda actually lives - it's a squashfs image that contains the installer's root filesystem.
There are a
lot of different ways for loader to find
install.img, but when you boot from DVD it's simple: loader notices the installer DVD, mounts it, and mounts
images/install.img as its root filesystem.
Once the stage2 image is mounted, loader starts Anaconda, which then starts up Xorg and puts a shell on
tty2 and all that nice stuff, and the installer really starts.
3. Does Anaconda installs Packages/*.rpm? If I wanted to add one in there can I and would it be installed ?
No, it doesn't just install everything there. It uses the
comps.xml file (in
repodata/) to decide which package groups are available (and what packages are in those groups) - that's how the package selection UI gets filled in.
If you add anything to the
Packages/ directory (like if you're trying to create a custom DVD image) and you want it to be installable, you'll need to use
createrepo to regenerate the
repodata/ directory. That will let you install your packages via kickstart, at least.
If you need them to show up in the UI, you'll need to edit
comps.xml as well.