vinodpanicker / tklbam-profiles

TurnKey Linux Backup and Migration profiles

Overview

This repository contains:

1. Profile hooks in hooks/

   Since TKLBAM 1.4, profile level hooks are supported. These are TKLBAM hooks that live inside the profile. They work just like the hooks in /etc/tklbam/hooks.d except that they need to be cryptographically signed by the TurnKey release key for security reasons.

   The idea is to use this to build up a library of hooks that are useful during migration (e.g., stopping/starting services to prevent serialization issues, tweaking a configuration file or upgrading a database schema, etc.)

   We don't use this enough yet, but the infrastructure is already there.

2. Path includes/excludes configurations in the top-level

   These are the plain text top-level configuration files which we use to determine which paths to index when TKLBAM profiles are generated. Most of them are empty.

   In a nutshell, these configurations are a list of filesystem paths to scan for changes.

   Each TurnKey app has its own configuration file that includes or excludes filesystem paths that we don't scan for changes in the "core" profile. In other words, all configurations inherit from "core".

   If the "core" configuration is sufficient, then the app-specific configuration will be empty. Most of them are empty.

What paths are we scanning changes to?

As per the embedded documentation from tklbam internal create-profile command:

In principle, we want to track changes to the user-servicable,
customizable parts of the filesystem (e.g., /etc /root /home /var
/usr/local /var /opt /srv) while ignoring changes in areas maintained by
the package management system.  The "Filesystem Hierarchy Standard"
describes the Linux filesystem structure.

Why not backup everything?

TKLBAM was originaly designed to make it easy for users to only backup the
delta (I.e., changes) from a fixed installation base (I.e., an appliance). In
this usage scenario, less is more.

By default we only backup your data and configurations, plus a list of new
packages you've installed. Later when you restore these will be overlaid on top
of the new appliance's filesystem and the package management system will be
asked to install the missing packages.

By contrast, If you backup the entire filesystem TKLBAM won't be able to help
you migrate your data and configurations to a newer version of an appliance.
The restore will just run everything over. At best you'll end up with the old
appliance in a new location. But more likely you'll end up mixing the old and
new filesystems and break the package management system.

For more detail:

$ tklbam internal create-profile --help
What is a backup profile?

A backup profile is used to calculate the list of system changes that need to
be backed up (e.g., new files and packages). It typically describes the
installation state of the system and includes 3 files:

* dirindex.conf: list of filesystem paths to scan for changes
* dirindex: index of timestamps, ownership and permissions for dirindex.conf paths
* packages: list of currently installed packages.

[ .. snip ..]