PKVLM - Debian installer preseed-based bootstrapping.

Performs unattended bare-metal installs of machines to a working state (i.e. such that Puppet can continue).

Generates customized debian-installer ISO images which contain host-specific debconf preseed data, config files and scripts.

Uses a customized isolinux.cfg to load the machine-specific preseed.cfg from /cdrom via kernel command line options, 

Also integrates with LVM/virt-install to create/install new libvirt-based machines on the local KVM host based on the customized media.

Supports bootstrapping puppet (package + config (server, ssl certs)).

## Files

The debian installer source image (i.e. what you download from debian.org) goes into:
    
    iso/debian-X.Y.Z-ARCH-netinst.iso

    XXX: hardcoded as `$INSTALLER_NAME` in pvklm-create

The installer image is unpacked to:

    images/debian-X.Y.Z-ARCH

From where it is copied to:

    image/debian-X.Y.Z-ARCH_HOSTNAME

Then the preseed data is processed/copied/templated/etc from:

    preseed/... -> image/debian-X.Y.Z-ARCH_HOSTNAME/...

    (varies based on chosen options. This also configures scripts to be executed/files to be copied after install)

And finally, the resulting customized host-specific ISO image is created at:

    iso/debian-X.Y.Z-ARCH_HOSTNAME.iso

## Operation

Booting from the .iso loads the syslinux bootloader (isolinux/isolinux.bin, isolinux/boot.cat), which then looks for

    isolinux/isolinux.cfg

Our isolinux.cfg (generated from preseed/isolinux.cfg) loads the kernel/initrd from /install[.amd], and supplies the
relevant kernel command-line arguments, which are processed by debian-installer:

    auto=true priority=critical preseed/file=${PRESEED_MOUNT}/${PRESEED_NAME} preseed/file/checksum=${PRESEED_CHECKSUM} --                      ${INSTALL_BOOT_CONSOLE} quiet

This loads our preseed.cfg (generated from preseed/preseed.cfg). The preseed.cfg then contains answers to all the d-i interactive
questions. The preseed.cfg takes care of automating the installer itself.

The preseed.cfg contains many templated variables, which are subsituted for variables defined in pvklm-create at ISO-creation time.

The preseed.cfg also loads additional preseed files (generated from preseed/*.cfg), e.g.:

    passwords.cfg       - crypted passwords; not under version control
    host.cfg            - configure additional software installed on the host (exim)

The preseed.cfg can also specify additional packages to install:

    $PRESEED_PACKAGES

    (defined within pkvlm-create)

After the main installation process is complete, the installer can also execute arbitrary script commands from our preseed.cfg
We use this to copy over configuration files from "$IMAGE/preseed-files" inside the ISO (generated from various files
in preseed/files and preseed/.../files (e.g. puppet)) to the target system. These are used for more advanced customizations than the debconf
preseeding lets us do:

    - configure serial console (/etc/default/grub, update-grub, modify /etc/inittab)
    - configure puppet (/etc/puppet/puppet.cfg, pre-install ssl certs to /etc/puppet/ssl)

Once the installer is complete, it will reboot, and the newly installed/bootstrapped Debian Linux system will start up for the first time.

If puppet was bootstrapped, the puppet agent will start its first run immediately (in the background via /etc/init.d/puppet, as normal).

## Usage

Some things are hardcoded in preseed/*
Some things are hardcoded in pklvm-create (the shell script)
Some things can be specified via `foo=...` options on the command line:

    ./pkvlm-create [options] <name> [name=[value] [...]]
    ./pkvlm-create asdf domain=test.pvl puppet_master=puppet-testing.paivola.fi

These options are defind in pkvlm-create. Not all variables in preseed/... are configureable via options.

The only required argument is the machine's name. It is given as the first non-option argument. 

## Puppet

Supports configuring the host as a puppet agent. Pass a puppet=yes opt:

    ./pkvlm-create asdf puppet=yes

The puppet server can be configured via `puppet_master=...`. It defaults to 'puppet' (i.e. match puppet's default behaviour to resolve a host called
'puppet').

### SSL

Supports pre-installing Puppet's SSL certificates from:

    preseed/puppet/ssl

If the puppetmaster's CA cert is present in preseed/puppet/ssl/certs/ca.pem, it is included in the preseed-files. 

You can also pre-generate a cert+pkey pair for the machine on the puppetmaster:

    puppet cert --generate ...
    scp $ssldir/{certs,private_keys}/...pem ...

These will be copied from "preseed/puppet/ssl/{certs,private_keys}/${FQDN}.pem" to the preseed-files, and the agent
will use them to connect to the puppetmaster.