Backup System Configuration

In this example, we automatically backup our system configuration.

From time to time, a system fails at pikt.org (for example, due to system disk failure), or we need to do an operating system upgrade.  (Or, heaven forbid, a system might get hacked.)  When we rebuild the system, after the OS reinstall, we need to restore the system to its previous configuration.  For this purpose, it's handy to have a backup of the essential system configuration.

The BackupSystemConfiguration script following does just that.

BackupSystemConfiguration

        init
                status =piktstatus
                level =piktlevel
                task "Backup system configuration"
                input proc "echo =hostname; echo =dmesg; echo =df; echo =crontab -l"

        begin
                =execwait "=cp /dev/null /usr/local/etc/syscfg"

        rule
                =execwait "$inlin >> /usr/local/etc/syscfg"
                =execwait "echo >> /usr/local/etc/syscfg"

In this script, we want to feed the standard Pikt input loop a series of commands, the output of which will be concatenated to a file, in this case /usr/local/etc/syscfg.  (We could just as easily have placed this file in the /etc directory.)  That is, we want the script input to be:

/bin/hostname
/bin/dmesg
/bin/df
/usr/bin/crontab -l
[...]

(and possibly other commands; we might add to the list over time).

One way to achieve this is by, as shown, echoing a series of commands in a Pikt 'input proc' statement.

Then, for each input command, we =execwait the command's output to the syscfg file.  Very simple.

Another way to do this would be to accomplish the script objective in a single 'begin' statement (doing this in an 'end' statement would work just as well):

        init
                status =piktstatus
                level =piktlevel
                task "Backup system configuration"

        begin
                =execwait "=hostname > /usr/local/etc/syscfg;
                           =dmesg >> /usr/local/etc/syscfg;
                           =df >> /usr/local/etc/syscfg;
                           =crontab -l >> /usr/local/etc/syscfg"

(Note, since we have no rule sections, hence there is no script input loop, there is no need to specify an 'input proc' statement.)

We have a companion script, backup_nightly.sh, that backs up each system's /usr/local directory to a central backup server.  So, on that backup server, we routinely save each system's /usr/local/etc/syscfg file in one central location.

This is just one program example.  You could write new scripts to:  backup each system's network configuration (example); backup each system's PIKT configuration (example); and so on.

For more examples, see Samples.