1 IPC::Locker

This is the IPC::Locker Perl Package.

1.1 Copyright

This package is Copyright 1999-2010 by Wilson Snyder <wsnyder@wsnyder.org>.

This program is free software; you can redistribute it and/or modify it under the terms of either the GNU Lesser General Public License Version 3 or the Perl Artistic License Version 2.0.

This code is provided with no warranty of any kind, and is used entirely at your own risk.

1.2 Description

This package provides a server for locks and a package for clients to access that server. The result is that clients can access named locks on a Internet wide bases, solving critical section problems without the mess of NFS or other file locking techniques.

1.2.1 IPC::Locker

IPC::Locker is a Perl package which allows cross cluster locking. For example: 

       my $lock = IPC::Locker->lock(host=>'example.std.com');
       ... Critical section ...
       $lock->unlock();

See `man IPC::Locker' after installation.

1.2.2 lockerd

lockerd is the daemon that supports IPC::Locker. See `man lockerd' after installation.

1.2.3 IPC::PidStat

IPC::PidStat is a Perl package which answers the question, "is pid X running on host Y?". See `man IPC::PidStat' after installation.

1.2.4 pidstat

pidstat is a program which answers the question, "is pid X running on host Y?". See `man pidstat' after installation.

1.2.5 pidstatd

pidstat is the daemon that supports IPC::PidStat and pidstat. See `man pidstatd' after installation.

1.2.6 pidwatch

pidwatch is a program which starts other programs, and kill that program when another job exists. See `man pidwatch' after installation.

1.2.7 uriexec

uriexec is a simple wrapper which allows executing a command which is quoted using URI escapes. This prevents layered shells from interpreting special characters. See `man uriexec' after installation.

1.2.8 check_lockerd and check_pidstatd

check_lockerd and check_pidstatd are Nagios plugins to check lockerd and pidstatd. See the Nagios documentation `http://www.nagios.org' for information on installing plugins.

1.3 Obtaining Distribution

The latest version is available at `http://www.perl.org/CPAN/'

Download the latest package from that site, and decompress. `gunzip IPC::Locker_version.tar.gz ; tar xvf IPC::Locker_version.tar'

1.4 Supported Systems

This version of IPC::Locker has been built and tested on:

It should run on any system with perl and TCP/IP socketing.

1.5 Installation

  1. `cd' to the directory containing this README notice.
  2. Type `perl Makefile.PL' to configure IPC::Locker for your system.
  3. Type `make' to compile IPC::Locker.
  4. Type `make test' to check the compilation.
  5. Type `make install' to install the programs and any data files and documentation.
  6. You may wish to install `lockerd' and `pidstatd' in a init.rc file so that it is run at system startup. Depending on your distribution, you may be able to just:

    `cp init.d/lockerd /etc/init.d/lockerd' (On one server only)

    `cp init.d/pidstatd /etc/init.d/pidstatd' (On all machines)

    Edit paths in above to point to /usr/bin instead of /usr/local/bin, if needed.

    `/etc/init.d/lockerd start' (On one server only)

    `/etc/init.d/pidstatd start' (On all machines)

    `chkconfig lockerd on' (On one server only)

    `chkconfig pidstatd on' (On all machines)

    If you get "This account is currently not available." you need to change the daemon account from a shell of /sbin/nologin to /sbin/bash.

  7. If you are using Nagios (`http://www.nagios.org'), sample scripts to check the daemons are included in the nagios subdirectory.