Overview

appliances can be monitored remotely.

Currently, a set of Nagios commands is provided to check the reachability, health and resource usage of appliances.

Nagios commands for appliances

Configuring the monitoring host for monitoring

On the monitoring host, the configuration of Nagios has to be modified. This is a simple process in a few steps:

1. define -specific commands
2. Listing appliances on your network 
3. verify the configuration
4. restart Nagios

Defining -specific commands

Download privateserver.commands.cfg and save it to your monitoring host as:

• /etc/nagios/objects/privateserver.commands.cfg
• /usr/local/nagios/etc/objects/privateserver.commands.cfg (if Nagios was installed from source code)

Include privateserver.commands.cfg from nagios.cfg with a line like the following:

# replace with the full path to your privateserver.commands.cfg
cfg_file=/etc/nagios/objects/privateserver.commands.cfg

Listing appliances on your network

Download privateserver.host.cfg.template. For each of your appliances:

1. make a copy of the template as appliance hostname.cfg, under the /etc/nagios/objects directory (or /usr/local/nagios/etc/objects, if Nagios was installed from source code)
2. open appliance hostname.cfg in an editor and:
   
   1. replace all occurrences of localhost.localdomain with the hostname of the appliance
   2. replace all occurrences of 127.0.0.1 with the IP address (recommended) or the hostname of the appliance
   3. save
3. include appliance hostname.cfg from another configuration file (e.g. /etc/nagios/nagios.cfg) with a line like the following:
   

   # replace with the full path to the configuration file
   cfg_file=/etc/nagios/objects/host1.privateserver.test.cfg

Configuration files created from the template require the following definitions to be already present in your Nagios configuration:

• linux-server host definition
• generic-service service definition

All of the above definitions are present in the default Nagios configuration, but they may be absent in your installation of Nagios

Verifying the Nagios configuration

Run the following command:

nagios -v /etc/nagios/nagios.cfg

# if you installed Nagios from source code, you might need to run this instead:
/usr/local/nagios/bin/nagios -v /etc/nagios.cfg

Review the output, and correct any errors reported by Nagios. Nagios only reports the first error it finds, so you will need to verify the configuration after every change, until it reports no errors.

Restarting Nagios

Run the following command:

systemctl restart nagios

Nagios will restart with the new configuration. The changes should be immediately visible in the web interface.

Configuring the appliance for Nagios monitoring

For remote monitoring to work, the appliance must be reachable from the monitoring host. Additionally, most commands need a specific appliance service to be assigned to the network interface used for management (for each command, it will be documented whether this is the case, and which service affects it). The service assignment UI can be found in the web console, under Server Configuration → Applications.

Edit /etc/nagios/nrpe.cfg and set allowed_host to the IP address of Nagios monitoring server.

Start nrpe service:

systemctl start nrpe

systemctl enable nrpe

Reachability checks

The commands in this category check for the reachability of the appliance's administration interfaces.

check_privateserver_ping

Checks whether the appliance responds to ping requests. For more information, see the documentation for the Nagios check_ping plugin.

Status

Output

A typical, healthy output is similar to:

PING OK - Packet loss = 0%, RTA = 33.22 ms

Service health checks

The commands in this category check whether the appliance's services, internal or external, are up and working correctly.

check_privateserver_sip

Performs a test call on the appliance to ensure that the SIP service can handle calls correctly. Requires the nrpe service to be enabled on the management network interface.

Status

Output

If the status is CRITICAL, the output contains the exit code of both participants to the test call. At least one will be non-zero, indicating an error. ...

check_privateserver_web_console

Checks that the web-based administration interface of the appliance is reachable and running correctly. Requires the http service to be enabled on the management network interface.

Status

check_privateserver_ssh_console

Checks that the appliance is reachable through SSH. Requires the ssh service to be enabled on the management network interface.

Status

check_privateserver_db_status

Checks that the database service on the appliance is running correctly. Requires the nrpe service to be enabled on the management network interface.

Status

check_privateserver_db_data

Checks that the database service on the appliance is responding to queries. Requires the nrpe service to be enabled on the management network interface.

Status

Resource usage checks

The commands in this category monitor the usage of the appliance's finite resources (CPU, memory, etc.).

check_privateserver_cpu

Checks the CPU usage on the appliance. Requires the nrpe service to be enabled on the management network interface.

Status

check_privateserver_memory

Checks the user and swap memory usage on the appliance. User memory is calculated as total memory usage minus buffers and cache. Requires the nrpe service to be enabled on the management network interface.

Status

check_privateserver_disk

Checks the disk space usage on the appliance. Requires the nrpe service to be enabled on the management network interface.

Status

check_privateserver_bandwidth

Checks the network bandwidth usage on the appliance. Requires the nrpe service to be enabled on the management network interface.

Status

Appendix: Attachments