Posted by: Mangesh_Linux_Administrator | August 6, 2010

Monitoring server


1) Make sure you get an e-mail every time root logs in!

ACTION

Edit your .bash_profile and include these lines:

echo ‘ALERT – Root Shell Access on:’ `date` `who` | mail -s “Alert: Root Access from `who | awk ‘{print $6}’`” your@email.com

your@email.com should be an external e-mail address for obvious reasons.

Another interesting thing you can do is to get a log of the commands ran by the root session after it logs out. To do this create a file called .bash_logout in root’s home directory (/root usually) with this content:

# ~/.bash_logout
history | uuencode commandlog.txt | mail -s “Alert: Root Access command log” your@email.com
clear

Just a warning about this, this will display fine in most e-mail clients but it is not compliant with the standards so it might not… gmail.com is an example where the log shows all garbage, although there’s an option there to make it look alright.

2)Set an SSH Legal Message

ACTION
To add a SSH legal message upon login, SSH into server and login as root.
At command prompt type: pico /etc/motd
Enter your message, save and exit.

3)Use LogWatch to get an e-mail with details parsed from your server logs.Apart from the normal instalation of LogWatch, to make it useful take these steps:

– edit the /usr/share/logwatch/default.conf/logwatch.conf
change: the email destination (external email is better) , set Detail to medium or high (I would set to high)

– edit /etc/logwatch/override.conf (originally this file is empty) and put these lines:
logfiles/exim: LogFile = exim_mainlog
logfiles/http: LogFile = /usr/local/apache/logs/access_log
services/pop3: *OnlyService = cpanelpop
services/pop3: *RemoveHeaders = 1
services/pure-ftpd: LogFile = messages

This overrides the logfiles and messages for some of the services, these are the working ones under cPanel 10.8 (not using maildir).

In my current version (Logwatch 7.2.1 and cPanel 10.8.1) both POP3 and Exim parsing does not work properly. I have recoded the POP3 perl script to output something useful, but this is work in progress still.

I am working on the Exim script now, but I am having serious problems with performance.

Once I have both script ready, I’ll post them here.

Pure ftpd is not working either, but I think this is a configuration issue, not a problem with the parser itself.

Run logwatch once from the command line and see if you like the emails. Tweak as necessary.

4)PRM – (Process Resource Monitor) . This tool does what it says on the tin.
Quick reference article, taken from Crucial Paradigm help pages:

How to install PRM (Process Resource Monitor)

PRM (Process Resource Monitor)

Introduction
PRM monitors the process table on a given system and matches process id’s with set resource limits in the config file or per-process based rules. Process id’s that match or exceed the set limits are logged and killed; includes e-mail alerts, kernel logging routine and more…

How it works?
PRM works on the basis that once a process id is found matching resource limits; there is a corresponding trigger and wait value. The trigger value increments upwards from zero (0) to the defined value, pausing the duration of seconds defined as wait value. There after the status of the flagged pid is checked again, if still above or equal to resource limits the trigger/wait cycle begins again till the max trigger value is reached. When this trigger value is reached the given process is logged/killed.

This all together has the effect that applications with short burst resource spikes (e.g: apache, mysql etc..) are not killed; but rather on applications with prolonged resource consumption. Using the rule system, you can define different wait/trigger/resource values for any application.

Installation
First we must fetch the package:
wget http://www.rfxnetworks.com/downloads/prm-current.tar.gz

And extract it:
tar xvfz prm-current.tar.gz

The current version of prm as of this writing is 0.3, so lets cd to the 0.3 extracted path:
cd prm-0.3/

And finally run the enclosed install.sh script:
./install.sh

Configuration
The prm installation is located at ‘/usr/local/prm’, and the configuration file is labeled ‘conf.prm’.

Open the ‘/usr/local/prm/conf.prm’ file with your preferred editor. There is an array of options in this file but we will only be focusing on the main variables.

Lets skip down to the user e-mail alert’s section and set the USR_ALERT value to ‘1′; enabling alerts.
# enable user e-mail alerts [0=disabled,1=enabled] USR_ALERT=”1″

And configure our e-mail addresses for alerts:
# e-mail address for alerts USR_ADDR=”root, you@domain.com”

Check the 5,10, or 15 minute load average; relative to the later option below for min. load level.
# check 5,10,15 minute load average. [1,2,3 respective of 5,10,15] LC=”1″

PRM optionally has a required load average for running. If the load is not equal to or greater than this value; PRM will not run. Setting this value to zero will force the script to always run but this should not be needed.
# min load level required to run (decimal values unsupported) MIN_LOAD=”1″

This is the introduction described wait value, used for pauses between trigger increments. The value of wait multiplied by the value of kill_trig equal the duration of time before a process is killed (10×3=30seconds).
# seconds to wait before rechecking a flagged pid (pid’s noted resource # intensive but not yet killed). WAIT=”10″

The trigger limit before processes are killed, described in detail in the above ‘wait’ description and introduction.
# counter limit that a process must reach prior to kill. The counter value # increases for a process flagged resource intensive on rechecks. KILL_TRIG=”3″

The max percentage of CPU a process should be allowed to use before PRM flags it for killing.
# Max CPU usage readout for a process – % of all cpu resources (decimal values unsupported) MAXCPU=”35″

The max percentage of MEM a process should be allowed to use before PRM flags it for killing.
# Max MEM usage readout for a process – % of system total memory (decimal values unsupported) MAXMEM=”15″

That is it; you should tweak the MAXCPU/MAXMEM limits to your desired needs but the defaults should be fine for most.

Usage
The executable program resides in ‘/usr/local/prm/prm’ and ‘/usr/local/sbin/prm’. The prm executable can receive one of two arguments:

-s Standard run
-q Quiet run

The log path for prm is ‘/usr/local/prm/prm_log’, as well pid specific logs are stored in ‘/usr/local/prm/killed/’.

A default cronjob for PRM is installed to ‘/etc/cron.d/prm’, and is configured to run once every 5 minutes.

There is a provided ignore file, to ignore processes based on string rules. The ignore file is located at ‘/usr/local/prm/ignore’. This file supports line separated ignore strings. As a default the strings ‘root, named and postgre’ are ignored by PRM; this script was not intended to monitor root processes but rather user land tasks. It could easily watch root processes by removing the given line in the ignore file but this is strongly discouraged.

5) Munin

Just install munin from your cPanel addons configuration page and check the stats!

A common problem is the MySQL plugin showing empty graphs after a while. This is, according to munin’s website, a bug in a Perl library used that causes the path to mysqladmin to be lost. Solution? Easy, just hardcode the path:

pico -w /etc/munin/plugin-conf.d/cpanel.conf

add this line to the [mysql*] section:

env.mysqladmin /usr/bin/mysqladmin

Mine looks like this:

[mysql*]
user root
group wheel
env.mysqladmin /usr/bin/mysqladmin

[exim_mailqueue]
group mail

[exim_mailstats]
group mail

[mailman]
user mailman

If this is not enough (and it wasn’t for me) it means that for some reason the mysql variables for username and password are not being read when munin runs the mysql plugins as root.

What I’ve done was to force the password to be read directly from the .my.cnf file from root’s home directory.

If you want to give this solution a try, replace env.mysqladmin /usr/bin/mysqladmin with env.mysqladmin /root/customMysqlAdmin. Next, create that new file with this content:

/usr/bin/mysqladmin -uroot -p`cat ~/.my.cnf | grep pass | sed s/pass// | sed s/=// | sed s/\”//g` $@

I know the sed’s dont look pretty but that was a quick and dirty way…

Just don’t forget to make it executable as well:

chmod +x ~/root/customMysqlAdmin

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