Server Monitoring With munin And monit On Debian Etch - Page 2

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Submitted by falko (Contact Author) (Forums) on Sun, 2007-05-13 17:24. ::

4 Install And Configure monit

To install monit, we do this:

apt-get install monit

Now we must edit /etc/monit/monitrc. The default /etc/monit/monitrc has lots of examples, and you can find more configuration examples on http://www.tildeslash.com/monit/doc/examples.php. However, in my case I want to monitor proftpd, sshd, mysql, apache, and postfix, I want to enable the monit web interface on port 2812, I want a https web interface, I want to log in to the web interface with the username admin and the password test, and I want monit to send email alerts to root@localhost, so my file looks like this:

cp /etc/monit/monitrc /etc/monit/monitrc_orig
cat /dev/null > /etc/monit/monitrc
vi /etc/monit/monitrc

set daemon  60
set logfile syslog facility log_daemon
set mailserver localhost
set mail-format { from: monit@server1.example.com }
set alert root@localhost
set httpd port 2812 and
     SSL ENABLE
     PEMFILE  /var/certs/monit.pem
     allow admin:test

check process proftpd with pidfile /var/run/proftpd.pid
   start program = "/etc/init.d/proftpd start"
   stop program  = "/etc/init.d/proftpd stop"
   if failed port 21 protocol ftp then restart
   if 5 restarts within 5 cycles then timeout

check process sshd with pidfile /var/run/sshd.pid
   start program  "/etc/init.d/ssh start"
   stop program  "/etc/init.d/ssh stop"
   if failed port 22 protocol ssh then restart
   if 5 restarts within 5 cycles then timeout

check process mysql with pidfile /var/run/mysqld/mysqld.pid
   group database
   start program = "/etc/init.d/mysql start"
   stop program = "/etc/init.d/mysql stop"
   if failed host 127.0.0.1 port 3306 then restart
   if 5 restarts within 5 cycles then timeout

check process apache with pidfile /var/run/apache2.pid
   group www
   start program = "/etc/init.d/apache2 start"
   stop program  = "/etc/init.d/apache2 stop"
   if failed host www.example.com port 80 protocol http
      and request "/monit/token" then restart
   if cpu is greater than 60% for 2 cycles then alert
   if cpu > 80% for 5 cycles then restart
   if totalmem > 500 MB for 5 cycles then restart
   if children > 250 then restart
   if loadavg(5min) greater than 10 for 8 cycles then stop
   if 3 restarts within 5 cycles then timeout

check process postfix with pidfile /var/spool/postfix/pid/master.pid
   group mail
   start program = "/etc/init.d/postfix start"
   stop  program = "/etc/init.d/postfix stop"
   if failed port 25 protocol smtp then restart
   if 5 restarts within 5 cycles then timeout

(Please make sure that you check processes only that really exist on your server - otherwise monit won't start. I.e., if you tell monit to check Postfix, but Postfix isn't installed on the system, monit won't start.)

The configuration file is pretty self-explaining; if you are unsure about an option, take a look at the monit documentation: http://www.tildeslash.com/monit/doc/manual.php

In the apache part of the monit configuration you find this:

   if failed host www.example.com port 80 protocol http
      and request "/monit/token" then restart

which means that monit tries to connect to www.example.com on port 80 and tries to access the file /monit/token which is /var/www/www.example.com/web/monit/token because our web site's document root is /var/www/www.example.com/web. If monit doesn't succeed it means Apache isn't running, and monit is going to restart it. Now we must create the file /var/www/www.example.com/web/monit/token and write some random string into it:

mkdir /var/www/www.example.com/web/monit
echo "hello" > /var/www/www.example.com/web/monit/token

Next we create the pem cert (/var/certs/monit.pem) we need for the SSL-encrypted monit web interface:

mkdir /var/certs
cd /var/certs

We need an OpenSSL configuration file to create our certificate. It can look like this:

vi /var/certs/monit.cnf

# create RSA certs - Server

RANDFILE = ./openssl.rnd

[ req ]
default_bits = 1024
encrypt_key = yes
distinguished_name = req_dn
x509_extensions = cert_type

[ req_dn ]
countryName = Country Name (2 letter code)
countryName_default = MO

stateOrProvinceName             = State or Province Name (full name)
stateOrProvinceName_default     = Monitoria

localityName                    = Locality Name (eg, city)
localityName_default            = Monittown

organizationName                = Organization Name (eg, company)
organizationName_default        = Monit Inc.

organizationalUnitName          = Organizational Unit Name (eg, section)
organizationalUnitName_default  = Dept. of Monitoring Technologies

commonName                      = Common Name (FQDN of your server)
commonName_default              = server.monit.mo

emailAddress                    = Email Address
emailAddress_default            = root@monit.mo

[ cert_type ]
nsCertType = server

Now we create the certificate like this:

openssl req -new -x509 -days 365 -nodes -config ./monit.cnf -out /var/certs/monit.pem -keyout /var/certs/monit.pem

openssl gendh 512 >> /var/certs/monit.pem

openssl x509 -subject -dates -fingerprint -noout -in /var/certs/monit.pem

chmod 700 /var/certs/monit.pem

Afterwards we edit /etc/default/monit to enable the monit daemon. Change startup to 1 and set CHECK_INTERVALS to the interval in seconds that you would like monit to check your system. I choose 60 (seconds) so my file looks like this:

vi /etc/default/monit

# Defaults for monit initscript
# sourced by /etc/init.d/monit
# installed at /etc/default/monit by maintainer scripts
# Fredrik Steen <stone@debian.org>

# You must set this variable to for monit to start
startup=1

# To change the intervals which monit should run uncomment
# and change this variable.
CHECK_INTERVALS=60

Finally, we can start monit:

/etc/init.d/monit start

Now point your browser to https://www.example.com:2812/ (make sure port 2812 isn't blocked by your firewall), log in with admin and test, and you should see the monit web interface. It should look like this:

(Main Screen)

(Apache Status Page)

Depending on your configuration in /etc/monit/monitrc monit will restart your services if they fail and send notification emails if process IDs of services change, etc.

Have fun!

 

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Submitted by enderst (not registered) on Wed, 2008-12-24 19:04.

how about instead of 'cat /dev/null > /etc/monit/monitrc'

use '>  /etc/monit/monitrc'

Submitted by Anonymous coward (not registered) on Sat, 2008-12-06 05:42.
dont forget to run "monit -t" to verify monit.conf syntax.
Submitted by Eder Gobbi (not registered) on Fri, 2008-10-17 13:34.

But, if the process set "zombie", and do not runing? The pid are yet in the /var/run...

Submitted by chillifire (registered user) on Fri, 2008-02-29 20:41.

I have munin and monit installed on my ISPConfi Servers and also Prelude/Prewikka - follwoing the HowTos on this site. Now, Prewikka gives web access to Prelude, OSSEC and Snort, but Munin, ISPConfig and Monit are still separate websites. So I thought why not use the generated Munin Overview screen as a linkscreen to all the different programs for all my servers?

As the Munin screens are generated, it is not a question of adjusting simple html. You need to edit /etc/munin/templates/munin-overview.tmpl. You will see some pseudo HTML code with many variables, which are obviously replaced at generation time. We will need to make adjustments in the middle:

 <TMPL_LOOP NAME="DOMAINS">
 <ul>
  <li><span class="domain"><a href="<TMPL_VAR NAME="DOMAIN">/index.html"><TMPL_VAR ESCAPE="HTML" NAME="DOMAIN"></a></span><TMPL_IF NAME="COMPARE"> :: [ <a href="<TMPL_VAR NAME="DOMAIN">/comparison-day.html">day</a> <a href="<TMPL_VAR NAME="DOMAIN">/comparison-week.html">week</a> <a href="<TMPL_VAR NAME="DOMAIN">/comparison-month.html">month</a> <a href="<TMPL_VAR NAME="DOMAIN">/comparison-year.html">year</a> ]</TMPL_IF>
      <ul>
        <TMPL_LOOP NAME="NODES">
        <li><span class="host"><a href="<TMPL_VAR NAME="DOMAIN">/<TMPL_VAR NAME="NODE">.html"><TMPL_VAR ESCAPE="HTML" NAME="NODE"></a></span> ::
        [ <TMPL_LOOP NAME="CATEGORIES"><a <TMPL_IF NAME="STATE_WARNING">class="warn"</TMPL_IF> <TMPL_IF NAME="STATE_CRITICAL">class="crit"</TMPL_IF> href="<TMPL_VAR NAME="DOMAIN">/<TMPL_VAR NAME="NODE">.html#<TMPL_VAR NAME="NAME">"><TMPL_VAR ESCAPE="HTML" NAME="NAME"></a> </TMPL_LOOP> <a target="_blank" href="https://<TMPL_VAR NAME="NODE">:2812/">Monit</a> <a target="_blank" href="https://<TMPL_VAR NAME="NODE">:81/">ISPConfig</a> ]</li>
        </TMPL_LOOP>
        <li><span class="host"><a target="_blank" href="https://prelude.<TMPL_VAR NAME="DOMAIN">">Prewikka Console</a></li>
 </ul>
   </li>
 </ul>
 </TMPL_LOOP>

The code in bold will generate the link to Monit and ISPConfig respective. The code in bold and italic will generate the link to prewikka/prelude, but assumes you created a subdomain (or a co-domain in ISPConfig) of the name prelude.yourdomain.com. The 'yourdomain.com' is replaced at runtime with the real name - in my case a .net domain actually - not .com.

Submitted by brianwc (registered user) on Wed, 2007-10-10 03:39.

Monit was not starting for me, and I found the error by looking at:

 tail /var/log/syslog

 which said "monit: /etc/monit/monitrc:123: Error: syntax error '"monit/token"'

 and I realized that the token file was actually at "/web/monit/token" and after making that change to /etc/monit/monitrc monit started properly. 

Others may set their root web directory to be /web and will not experience this problem, but for those who don't this is a fix.