-Instalation
-===========
+Installation
+============
Doing something very complex in ~100 SLOC_ is not easy, unless you're standing
in the shoulders of giants. I'm standing in the shoulders of rsync_ mainly, so
1. ``/etc/bacaprc``
2. ``/etc/bacap/bacaprc``
3. ``bacaprc`` in the same directory as the ``bacap`` script
+4. Optional parameter passed as argument to the script
+5. ``$CONFIG_PATH/$HOST/bacaprc``
Order is important, since all files are read (if possible) and values in the
last configuration file read overwrites old values. The script takes an optional
-parameter, which is another location to look for a configuration file. The
-configuration file passed as argument will be read last, and an error will be
-printed if can't be found (no error is issued if any of the other configuration
-files are missing).
+parameter, which is another location to look for a configuration file. If the
+configuration file passed as argument can't be found, an error will be printed
+(no error is issued if any of the other configuration files are missing).
+Also, config options could be specified on a per host basis by creating a
+``bacaprc`` file in ``$CONFIG_PATH/$HOST``. As a side effect of this,
+configuration file(s) are read initially and each time the script backups a new
+host. So the configuration file(s) are read at least two times even if you
+backup one host.
The configuration file is a Bash_ script too, and these are the default values:
mkdir -p $CONFIG_PATH
-The create a directory for each host you want to backup there, the directory
+Then create a directory for each host you want to backup there, the directory
name should be the name of the host (as you would use to connect to it using
ssh_). For now let's say we will only backup ``localhost``::
``/etc`` and ``/home``::
echo /etc > $CONFIG_PATH/$LOCALHOST/paths
- echo /home > $CONFIG_PATH/$LOCALHOST/paths
+ echo /home >> $CONFIG_PATH/$LOCALHOST/paths
But sometimes there are things there that you don't want to backup, in that
case you can create a file named ``excludes`` too, and write which paths you
echo /home/rata/ > $CONFIG_PATH/$LOCALHOST/excludes
+Also, if you don't want to exclude files matching some pattern, you can create
+a file named ``includes`` with the patterns you want to include (you can use
+anything supported by the ``--include-from`` rsync_ option)
+
That's pretty much it. If you want to add other hosts, just create the host
directory and the needed host configuration files.
-You may want to automate it using *cron*. I will not include a *cron* tutorial
-here, but if you are completely lost, you can add this line to ``/etc/crontab``
-to make a daily backup at 6:30::
-
- 25 6 * * * root /path/to/bacap
-
-If you are a Debian_ user, you can also simply install the script in
-``/etc/cron.daily`` (or make a symlink or something similar) and you are set.
-
-.. _Debian: http://www.debian.org/
-
Usage
+Tips
+====
+
+Here are a few tips on how to configure Bacap_ for several common scenarios.
+
+Automating backups using cron
+-----------------------------
+
+You probably want to automate your backup using *cron*. I will not include
+a *cron* tutorial here, but if you are completely lost, you can add this line to
+``/etc/crontab`` to make a daily backup at 6:30::
+
+ 30 6 * * * root /path/to/bacap
+
+If you are a Debian_ user, you can also simply install the script in
+``/etc/cron.daily`` (or make a symlink or something similar) and you are set.
+
+.. _Debian: http://www.debian.org/
+
+
+Providing a ssh_ key
+--------------------
+
+When doing a backup of a remote host, you probably want ssh_ to be able to
+login without providing a password. To do so, you can generate a ssh_ key using
+``ssh-keygen``, copy the public key to the target's
+``/root/.ssh/authorized_keys`` using ``ssh-copy-id root@host`` (or the user
+that runs the backup) and set the Bacap_ configuration variable ``RSYNC_RSH``
+to something like::
+
+ RSYNC_RSH="ssh -i /path/to/priv-key -o NumberOfPasswordPrompts=0"
+
+The ``-o NumberOfPasswordPrompts=0`` is not necessary, but you would appreciate
+it if something is wrong with your key, since if you don't use it, rsync_ will
+hang asking for a password.
+
+Also, you may consider using ``StrictHostKeyChecking=no`` ssh option if you
+backup hosts with dynamic IP address.
+
+
+Backup local networks nodes (or nodes with a fast connection)
+-------------------------------------------------------------
+
+When the bandwidth is not tight, you probably want to ensure ssh_ doesn't use
+compression::
+
+ RSYNC_RSH="ssh -o Compression=no"
+
+And if your network is trusted, you probably don't need very strong encryption
+either::
+
+ RSYNC_RSH="ssh -o Compression=no -c arcfour"
+
+
+Listing differences between 2 snapshots
+---------------------------------------
+
+If you want to see what have actually changed between two backups you can run
+rsync_ with your usual flags plus ``-nv --delete``. For example if you just use
+``-a``, to see the differences between ``lolaus/2010-07-11`` and
+``lolaus/2010-07-12`` you can run::
+
+ rsync -nav --delete lolaus/2010-07-11/ lolaus/2010-07-12/
+
+
+
Similar alternatives
====================
projects / software / bacap.git / blobdiff