Main Page/Nagios add Indirect Host and Service Checks: Difference between revisions

Revision as of 17:47, 30 October 2013

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NAGIOS INDIRECT MAPPING OF HOSTS

For Environments that have multiple servers and only one server or firewall is accessible directly i.e one server is accessible and all others may be accessed through it internally . Nagios mapping may be done via Indirect Host and Service Checks using nrpe.

Indirect checks are useful for: Monitoring "local" resources (such as disk usage, processer load, etc.) on remote hosts

Monitoring services and hosts behind firewalls

Obtaining more realistic results from checks of time-sensitive services between remote hosts (i.e. ping response times between two remote hosts)

Indirect service check Senario :

As in 2coms there is a backup server associated with the main server indirectly accessible via the mailserver

Access IP : zimbraserver.2coms.com/115.248.160.99

Mailserver Internal Ip : 192.168.1.3 ( primary server)

Backup server Ip :`192.168.1.5 (secondary server)

Procedure Taken :

on directly accessible ( primary ) server :

1. Access mail-server ( server already mapped as directly accesible )

2. Install check_nrpe plugin if not present

yum install nagios-plugins-nrpe

3. now add entry in nrpe.cfg for each service you want to check on the secondary/passive server as shown below :

COMMANDS FOR MAIN SERVER

command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10

command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20

command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 7% -c 5% -p /dev/sda3

command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z

command[check_cpu]=/usr/local/nagios/libexec/check_cpu.sh -w 60 -c 70

command[check_mem]=/usr/local/nagios/libexec/check_mem_avail -w 130 -c 150

command[check_clam]=/usr/local/nagios/libexec/check_clamd -H localhost

command[check_queue]=/usr/local/nagios/libexec/check_postfix_queue -w 300 -c 500

command[check_zimbra_clam_ud]=sudo -u zimbra /usr/local/nagios/libexec/check_clamav -w 2 -c 5

command[check_zimbra_lmtp]=/usr/local/nagios/libexec/check_smtp -H localhost -p 7025 -e '220 zimbraserver.2coms.com Zimbra LMTP server ready'

following commands are for backup server 192.168.1.5

command[check_users2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_users

command[check_load2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_load

command[check_hda12]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_hda1

command[check_hda22]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_hda2

command[check_hda32]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_hda3

command[check_zombie_procs2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_zombie_procs

command[check_cpu2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_cpu

command[check_mem2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_mem

command[check_clam2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_clam

command[check_queue2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_queue

command[check_zimbra_lmtp2]=/usr/local/nagios/libexec/check_nrpe -H 192.168.1.5 -c check_zimbra_lmtp

on Secondary ( Backup ) server :

Install nrpe and nagios plugins :

# yum install nrpe nagios-plugins-all

edit nrpe.cfg as follows :

allowed_hosts=127.0.0.1,192.168.1.3

And also add plugin definition as :

command[check_users]=/usr/lib64/nagios/plugins/check_users -w 5 -c 10

command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20

command[check_hda1]=/usr/lib64/nagios/plugins/check_disk -w 7% -c 5% -p /dev/hda3

command[check_hda2]=/usr/lib64/nagios/plugins/check_disk -w 7% -c 5% -p /dev/hda1

command[check_hda3]=/usr/lib64/nagios/plugins/check_disk -w 10% -c 5% -p /dev/sda1

command[check_zombie_procs]=/usr/lib64/nagios/plugins/check_procs -w 5 -c 10 -s Z

command[check_cpu]=/usr/lib64/nagios/plugins/check_cpu.sh -w 60 -c 70

command[check_mem]=/usr/lib64/nagios/plugins/check_mem_avail -w 130 -c 150

command[check_clam]=/usr/lib64/nagios/plugins/check_clamd -H localhost

command[check_queue]=/usr/lib64/nagios/plugins/check_postfix_queue -w 300 -c 500

Restart nrpe on this server

Restart nrpe on Primary server

On Nagios Server :

Add Host entry in /usr/local/nagios/etc/objects/linux-box.cfg with Access Ip :

Entries for Primary Server :

define host{

            use        linux-server
            host_name  zimbraserver.2coms.com
            alias      zimbraserver.2coms.com
            address    182.71.172.155
            hostgroups  Tetra Clients  ; Host groups
          }

Entries for Secondary Server :

define host{

            use        linux-server
            host_name  backupserver.2coms.com
            alias      backupserver.2coms.com
            address    182.71.172.155
            hostgroups  Tetra Clients  ; Host groups
          }

Note : address field is same for both host

add service definition in /usr/local/nagios/etc/service/backupserver.2coms.com.cfg for all services already defined in nrpe.cfg on primary host

eg :

define service{

              use                      generic-service
              host_name                backupserver.2coms.com
              service_description      Current Users
              check_command            check_nrpe!check_users2
             }

check nagios configuration /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Reload nagios configuration /etc/init.d/nagios reload

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 '''NAGIOS INDIRECT MAPPING OF HOSTS'''