2. Install the Configuration Files

There are several configuration files that need to be set up for Nagios. Use the following instructions to install and setup the configuration files for Nagios:

Extract the Nagios configuration files.
From the scripts.zip file (downloaded in Download Companion Files), copy the files from configuration_files/nagios directory to a temporary directory.
The nagios directory contains two sub-directories, objects and plugins.
Copy the configuration files.
1. Copy the contents of the objects directory to /etc/nagios/objects :
```
cp $tmp-directory/nagios/objects /etc/nagios/objects
```
2. Copy the contents of the plugins directory to the following location:
```
cp $tmp-directory/nagios/plugins /usr/lib64/nagios/plugins
```
Set the Nagios Admin password.
1. Choose a Nagios administrator password, for example, admin.
2. Use the following command to set the password:
```
htpasswd -c -b  /etc/nagios/htpasswd.users nagiosadmin admin
```
Set the Nagios Admin email contact address. Edit the /etc/nagios/objects/contacts.cfg file and change the nagios@localhost value to the admin email address for receiving alerts.

Edit the /etc/nagios/nagios.cfg file to add the following values in the OBJECT CONFIGURATION FILE(S) section:

# Definitions for hadoop servers
cfg_file=/etc/nagios/objects/hadoop-commands.cfg
cfg_file=/etc/nagios/objects/hadoop-hosts.cfg
cfg_file=/etc/nagios/objects/hadoop-hostgroups.cfg
cfg_file=/etc/nagios/objects/hadoop-services.cfg
cfg_file=/etc/nagios/objects/hadoop-servicegroups.cfg

Set Hosts.

Edit the /etc/nagios/objects/hadoop-hosts.cfg file and add a "define host { … }" entry for each host in your cluster using the following format:

define host {
       alias @HOST@
       host_name @HOST@
       use linux-server
       address @HOST@
       check_interval 0.25
       retry_interval 0.25
       max_check_attempts 4
       notifications_enabled 1
       first_notification_delay 0 # Send notification soon after
                                   change in the hard state
       notification_interval 0    # Send the notification once
       notification_options       d,u,r
  }

Replace the "@HOST@" with the hostname.

Set Host Groups

Open /etc/nagios/objects/hadoop-hostsgroups.cfg with a text editor.
Create host groups based on all the hosts and services you have installed in your cluster. Each host group entry should follow this format:
```
define hostgroup {
       hostgroup_name  @NAME@
       alias           @ALIAS@
       members         @MEMBERS@
   }
```
Where

Table 12.1. Host Group Parameters
Parameter Description

@NAME@

The host group name

@ALIAS@

The host group alias

@MEMBERS@

A comma-separated list of hosts in the group

Parameter	Description
`@NAME@`	The host group name
`@ALIAS@`	The host group alias
`@MEMBERS@`	A comma-separated list of hosts in the group

The following table lists the core and monitoring host groups:

Table 12.2. Core and Monitoring Hosts

Service	Component	Name	Alias	Members
All servers in the cluster		all-servers	All Servers	List all servers in the cluster
HDFS	NameNode	namenode	namenode	The NameNode host
HDFS	SecondaryNameNode	snamenode	snamenode	The Secondary NameNode host
MapReduce	JobTracker	jobtracker	jobtracker	The Job Tracker host
HDFS, MapReduce	Slaves	slaves	slaves	List all hosts running DataNode and TaskTrackers
Nagios		nagios-server	nagios-server	The Nagios server host
Ganglia		ganglia-server	ganglia-server	The Ganglia server host

The following table lists the ecosystem project host groups:

Table 12.3. Ecosystem Hosts

Service	Component	Name	Alias	Members
HBase	Master	hbasemaster	hbasemaster	List the master server
HBase	Region	regions-servers	region-servers	List all region servers
ZooKeeper		zookeeper-servers	zookeeper-servers	List all ZooKeeper servers
Oozie		oozie-server	oozie-server	The Oozie server
Hive		hiveserver	hiverserver	The Hive metastore server
WebHCat		twebhcat-server	webhcat-server	The WebHCat server

Set Services.
1. Open /etc/nagios/objects/hadoop-services.cfg with a text editor.
  This file contains service definitions for the following services: Ganglia, HBase (Master and Region), ZooKeeper, Hive, WebHCat, and Oozie
2. Remove any services definitions for services you have not installed.
3. Replace the @NAGIOS_BIN@ and @STATUS_DAT@ parameters as shown below:
  - For RHEL and CentOS
    @STATUS_DAT@ = /var/nagios/status.dat @NAGIOS_BIN@ = /usr/bin/nagios
  - For SLES
    @STATUS_DAT@ = /var/lib/nagios/status.dat @NAGIOS_BIN@ = /usr/sbin/nagios
4. If you have installed Hive or Oozie services, replace the parameter @JAVA_HOME@ with the path to the Java home. For example, /usr/java/default.
Set Status.
1. Open /etc/nagios/objects/hadoop-commands.cfg with a text editor.
2. Replace the @STATUS_DAT@ parameter with the location of the Nagios status file as shown below:
  - For RHEL and CentOS
    /var/nagios/status.dat
  - For SLES
    /var/lib/nagios/status.dat

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