munin-node

• munin-node installed via epel repository.
  
• Install perl-Cache-Cache:
  
  # yum install munin-node perl-Cache-Cache
• Create file "/etc/munin/plugin-conf.d/mysql" with below contents:
  
  [mysql*]
env.mysqluser munin
env.mysqlpassword {PASS}
• Create mysql user and assign corresponding privileges:
  
  mysql> create user munin@localhost identified by '{PASS}';
mysql> GRANT PROCESS, SUPER ON *.* TO 'munin'@'localhost';
mysql> GRANT SELECT ON `mysql`.* TO 'munin'@'localhost';
mysql> flush privileges
• Check the suggestions and install the plugins:
  
  munin-node-configure  --suggest 2>/dev/null |grep mysql
munin-node-configure  --shell | grep mysql | sh
• Test via:
  
  # cd /etc/munin/plugins
# munin-run mysql_connections

While setting up munin to monitor postgresql, I was getting "[DBD::Pg not found, and cannot do psql yet]" when running `munin-node-configure --suggest | grep postgres`.

I confirmed that the rpm package "perl-DBI-1.52-2.el5" was indeed installed.

However, when I ran a test against the module, it failed with:

On checking the library, it returned with "libpq.so.4 => not found":

Indeed libpq.so.4 was missing since postgresql90-libs was installed which only includes "libpq.so.5".

To get libpq.so.4, "compat-postgresql-libs" package needed to be installed.

Once installed the perl module test passed and I was able to get the munin plugins linked using:

Get status of apache (80) and lighttpd (81) on different ports:

This is done at the nodes.

1. Enable apache server-status in httpd.conf :
   
   <Location /server-status> 
    SetHandler server-status
    Order deny,allow
    Deny from all
    Allow from 127.0.0.1
</Location>
2. Enable lighttpd server-status in lighttpd.conf :
   
   $HTTP["remoteip"] == "127.0.0.1" {
status.status-url          = "/server-status"
}
3. Create /etc/munin/plugin-conf.d/apache:
   
   [apache*]
env ports="80 81" 

   * Test with:
   

   ports="80 83" /etc/munin/plugins/apache_processes

lighttpd idle process will be a straight line as total of busy and idle process is always the same when drawn as STACK, . To change this to LINE1:

At the host, edit "/etc/munin/munin.conf" and add the below line to the corresponding host:

HDD Temperature

You can usually identify which hard disks are on your system by looking in "/proc/ide" and in "/proc/scsi".

`fdisk -l` lists the two drives as "sda" and "sdb".