Russ Greenwald

Xen on Centos – Migrating a legacy server

Do you have a legacy server, running legacy software, still used by your company or worse a client?  Are the developers and engineers who set it up long gone, do you have documentation on the design, anything?  No worries… I recently ran into this situation and I’ve found a very nice solution. Continue reading

I’ve been using wiki’s for some time from phpwiki, mediawiki, etc.  They all have some pro’s and con’s.  I still like the php wiki, twiki, very much, and the java wiki, JSPWiki, but I have also grown to like XWIKI, http://xwiki.org.

It is a tomcat driven wiki with all the data in mysql, instead of txt files like the aforementioned wiki’s.  This makes for good security, backup, recovery, etc.  Albeit it does seem to run a little slower.  Below are my basic install notes, enjoy… Continue reading

My Favorite

– Tell Your Users What You Are Going to Do

– Tell Your Users What You Are Doing

– Tell Your Users What You Have Done

http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/admin-primer/

In .profile (if you use MacPorts) or .bash_profile

export TERM=xterm-color alias ls=’ls -G’ alias ll=’ls -hl’

/usr/share/horde/config/conf.php

Change the following line;

$conf[‘auth’][‘checkip’] = true;

to be this;

$conf[‘auth’][‘checkip’] = false;

Nagios + Cacti + NPC Plugin Install Instructions on Centos 5 I will post a full Nagios 3.x installation instruction later (yum install nagios). For the below, I will assume you have Nagios 3.x running and have a basic knowledge of Linux, file paths, commands, etc. Continue reading

• Installed using Yum Install Nagios
• Installed to /etc/nagios
  • nagios.cfg defines the commands file and location of the other config files
  • commands.cfg defines the scripts located in /usr/lib or lib64/nagios/plugins/ to be run
    • i.e. $USER1$/check_http -H $HOSTADDRESS$ -S -a nagioscheck:nag1oscheck
  • Within /etc/nagios/etc there are hosts.cfg, services.cfg, servicegroups.cfg, hostgroups.cf, contacts.cfg, and contactgroups.cfg
  • hosts.cfg contains any device that needs to be monitored
  • services.cfg defines the specific monitoring service and warning/critical parameters if any
  • servicgroups.cfg is used to organize in the web view
  • hostgroups.cfg matches the hosts in hosts.cfg to the services in services.cfg
  • In order to login to nagios, the ldap user must be listed in the contacts.cfg and assigned to a contactgroup
• After making changes in nagios run “/usr/bin/nagios -v /etc/nagios/nagios.cfg” to make sure there are not any mistakes
• service nagios restart

Logrotate is an amazing tool for linux admins.  It is service called by cron in the daily cron job.  Logrotate gives you options on how you want to manage any log file.

• Archive
• Compress
• Reset
• etc.

To configure logrotate for specific log files from Apache, tomcat, subversion, hudson, etc.

• Go to /etc/logrotate.d
• Create seperate configuration files for each application’s log file
• /var/log/http/* { create 0640 apache apache   #This line defines who is going to own the new log file after the old one is archived and compressed missingok daily # Run this daily rotate 7 # Rotate logs every 7 days, from line above compress # Compress log files }
• Save and check.  To test “logrotate -f /etc/logrotate.d/filename”