Chapter 15. How to use a wrapper
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Chapter 15. How to use a wrapper


Bert de Ridder

Original text

Stefan G. Weichinger

XML-conversion; Updates
AMANDA Core Team
<sgw@amanda.org>

Note

Refer to http://www.amanda.org/docs/howto-wrapper.html for the current version
of this document.

Note

The script used in this document is not part of the official AMANDA release.
The AMANDA core team does not take any responsibility for this script.
This is a mini-howto explaining how to control other running tasks on a server
where the AMANDA software is used to backup data.
Problem : Lots of software is picky about their datafiles being backed up while
the files are in use. It sometimes is even necessary to know the state of the
datafiles at the moment of backup so that when restoring you know exactly
*what* you are restoring. And most of the time there are dependencies between
the datafiles as well (for instance, the pure datafiles and the controlfiles of
an Oracle database.)
The solution is actually quite simple; you just use a custom made backupscript
instead of the standard tar command. Inside this tar command, you do some
necessary processing before executing the tar command and - if necessary - do
some more processing. This way, you can easily stop an Oracle database, tar the
files, send them to the tape server and restart the Oracle database. This of
course is just an example, anything you can do in a shell script can be done.

  1. Create the script
     This is the most important step, this script is the work horse of the
     solution. I've called it /bin/amandatar. You can call it whatever you want
     though. It's a Perl script, it may not be very pretty code, but it does
     the job. In the script, an example is given for the backup of a Lotus
     Notes Domino server.

       #!/usr/bin/perl

       # Tar wrapper for Amanda's tar.
       #

       use Getopt::Long qw(:config pass_through);

       # Obtain directory and file information from the command line.

       $result = GetOptions (
        'directory=s' => \$dir,
        'file=s' => \$file
       );

       # Check whether Amanda wants to do some administrative task (eg.
       indexinfo
       # or obtain the number of bytes to be backed up)
       # if file = /dev/null it's an administrative task and most of the time,
       no extra
       #   processing is necessary.

       # What you see here is just a log of the backup start time, and – more
       important
       #   the stopping of the domino server

       if ( $file ne '/dev/null' )
       {
         if ( $dir eq '/local/notesdata' )
         {
           system "echo 'Start backup notes at ' >> /var/lib/amanda/runtime" ;
           system "date >> /var/lib/amanda/runtime";
           system ( "/etc/init.d/domino stop >> /var/lib/amanda/runtime" );
         }
       }

       # The command line is being 'reconstructed'. Necessary because the
       GetOptions
       #   call above has stripped the file and directory information.
       # This is what I meant with 'ugly'  code ;-)

       while ( $ARGV[0] ne '' )
       {
         $val = $ARGV[0] ;
         unshift ( @NEWARGV, $val, ) ;
         shift @ARGV;
       }

       while ( $NEWARGV[0] ne '' )
       {
         $val = $NEWARGV[0] ;
         unshift ( @ARGV, $val ) ;
         shift @NEWARGV;
       }

       if ( $dir ne '' )
       {
         unshift ( @ARGV, '--directory', $dir );
       }
       if ( $file ne '' )
       {
         unshift ( @ARGV, '--file', $file );
       }

       if ( $file ne '/dev/null' )
       {
         system "echo 'Backing up directory ' $dir >> /var/lib/amanda/runtime"
       ;
       }

       # And finally make sure tar is called :-)
       #   (path may differ on your installation)
       unshift ( @ARGV , "/bin/tar" ) ;

       system ( @ARGV ) ;

       # Postprocessing
       #
       # If Notes backup was requested, restart the server.
       # Log the backup end time.
       #

       if ( $file ne '/dev/null' )
       {
         if ( $dir eq '/local/notesdata' )
         {
           system ( "/etc/init.d/domino start >> /var/lib/amanda/runtime" );
           system "echo 'End backup notes at ' >> /var/lib/amanda/runtime" ;
           system "date >> /var/lib/amanda/runtime";
         }
       }

       exit 0;

       # End script

     On some systems it may be necessary to setuid root the script.
  2. Rebuild AMANDA so that it uses your newly created script.
     Download the sources, untar them to a directory. I'm sure there are lots
     of documents already available on how to do this, so I won't go into too
     much detail. (Refer to Amanda_Installation_Notes).
     fast path :

       /usr/local/src # tar -xvzf amanda-source.tar.gz
       /usr/local/src # cd amanda-version
       /usr/local/src/amanda-version # ./configure \
         --with-user=amanda \
         --prefix=/usr/local \
         --exec-prefix=/usr \
         --bindir=/usr/bin \
         --sbindir=/usr/sbin \
         --libexecdir=/usr/lib/amanda \
         --with-configdir=/etc/amanda \
         --with-group=disk \
         --with-gnutar=/bin/amandatar \
         --with-gnutar-listdir=/var/lib/amanda/gnutar-lists \
         --with-tmpdir=/tmp/amanda \
         --with-smbclient=/usr/bin/smbclient \
         --mandir=/usr/local/man

     Here, it may be necessary to adjust some paths to match your installation.
     This setup works on SuSE Linux (also SLES) and MacOSX although you may
     have to use another binary tar.
     As you see, you may also "replace" the smbclient if necessary. I haven't
     yet tested it though. I'll leave it as an exercise for the reader <g>.

       /usr/local/src/amanda-version # make
       /usr/local/src/amanda-version # make install

     Now proceed as with a "normal" installation.

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