OpenSUSE Tumbleweed : Nagios Server

Nagios Server

Nagios is an open-source monitoring solution that runs on Linux.
Nagios was developed by Ethan Galstad and first released in 1999. Subsequently, the project was refined as an open-source project by several contributors.。

Nagios is designed to periodically check critical parameters of networks, applications, or servers. These parameters include microprocessor load, number of running processes, log files, disk and memory usage, as well as many other services such as SMTP (Simple Mail Transfer Protocol), HTTP (Hypertext Transfer Protocol), and POP3 (Post Office Protocol 3).

To run Nagois, you need PHP, a database such as MySQL, and a web server such as Apache or Nginx. This time, we will proceed assuming all of these are already configured.

1.Nagios Install

2. Creating Nagios Web Users

Create a user account to access the Nagios Web dashboard. This user account is used for authentication.
The default user name is nagiosadmin, defined as the preferred user name within the /etc/nagios/cgi.cfg file.

Set ownership and permissions

Restart Apache

Open the HTTP service port in the firewall.

Create the necessary directories and set ownership.

Editing Nagios System Services
Add Type=single to [Service]

Start and Enable Nagios Services

Restart the system

Verify that the service is running

3. Access the Nagios Web Interface

Access http://[IP_Address]/nagios/ in any browser. Enter nagiosadmin for [Username] and the password you specified when creating the user above for [Password], then click [Sign in].

After successfully logging in, the following dashboard will be displayed.

Display host availability
Click [Hosts] in the left menu

Click [Tactical Overview] in the left menu to view monitoring data.

Click [Current Status] [Services] in the left menu.

4. Configuring the Nagios Agent

What is required to monitor agents
• Nagios plugins for data collection
• NRPE Agent that executes plugins

4.1 Nagios plugins

Nagios plugins are located in the /usr/lib/nagios/plugins directory. To list all plugins available on the system, list this directory.

The following nagios-plugins are available:

4.2 Installing the Nagios NRPE Agent

Version Check

Start the service and enable it

Check the status of the NRPE agent

Open the NRPE port on the firewall
NRPE uses TCP port 5666 by default. If a firewall is in operation, open this port to allow external checks from the Nagios monitoring server.

Verify that port 5666/tcp is listening.

5. Add Monitoring Host

Add the following server as a host and configure it as a target for simple ping-based uptime monitoring.
OS : openSUSE15.6
IPアドレス　:　192.168.11.85

5.1 Editing Configuration Files

5.2 Directory Creation

5.3 Create New Definition File

5.4 Nagios Server Restart

Log in to the Nagios server (http://[server IP address]/nagios) and view Hosts to see that the host has been added.

6. Add Monitoring Service

Add the monitoring service to the host added above.
OS : openSUSE15.6
IPアドレス　:　192.168.11.85

6.1 Settings on the monitored server

6.1.1 Install the agent on the monitored host
Install nrpe and representative service plugins from EPEL

6.1.2 Editing Configuration Files

6.1.3 Enable and start the NRPE server

6.1.4 Open NRPE ports 5666/tcp and 5666/udp on the firewall.

6.2 Nagios Server-Side Configuration

6.2.1 Installing the NRPE Plugin

6.2.2 Check the Nagios plugin directory

check_breeze    check_dummy         check_ifstatus  check_nntp      check_overcr      check_simap  check_ups                   check_by_ssh    check_file_age      check_imap      check_nntps     check_ping        check_smtp   check_users                 check_clamd     check_flexlm        check_ircd      check_nrpe      check_pop         check_spop   check_wave                  check_cluster   check_ftp           check_jabber    check_nt        check_procs       check_ssh    negate                      check_dhcp      check_host          check_load      check_ntp       check_procs_perf  check_ssmtp  nrpe_check_control          check_dig       check_http          check_log       check_ntp_peer  check_real        check_swap   urlize                      check_disk      check_icmp          check_mailq     check_ntp_time  check_rpc         check_tcp    utils.pm                    check_disk_smb  check_ide_smart     check_mrtg      check_nwstat    check_rta_multi   check_time   utils.sh                    check_dns       check_ifoperstatus  check_mrtgtraf  check_oracle    check_sensors     check_udp

6.2.3 Editing commands.cfg

6.2.4 Edit and add to the korodes.cfg file created when adding the host earlier.
This time, let's add HTTP, SSH, and FTP.

6.2.5 Nagios Restart

6.2.6 Access http://[Nagios Server IP Address]/nagios
The newly added monitoring service has been added as shown in the figure below.