2 Agent

Overview

Zabbix agent is deployed on a monitoring target to actively monitor local resources and applications (hard drives, memory, processor statistics, etc.).

The agent gathers operational information locally and reports data to Zabbix server for further processing. In case of failures (such as a hard disk running full or a crashed service process), Zabbix server can actively alert the administrators of the particular machine that reported the failure.

Zabbix agents are highly efficient because of the use of native system calls for gathering statistical information.

Passive and active checks

Zabbix agents can perform passive and active checks.

In a passive check the agent responds to a data request. Zabbix server (or proxy) asks for data, for example, CPU load, and Zabbix agent sends back the result.

Active checks require more complex processing. The agent must first retrieve a list of items from Zabbix server for independent processing. Then it will periodically send new values to the server.

Whether to perform passive or active checks is configured by selecting the respective monitoring item type. Zabbix agent processes items of type 'Zabbix agent' or 'Zabbix agent (active)'.

Supported platforms

Pre-compiled Zabbix agent binaries are available for the supported platforms:

• Windows (all desktop and server versions since XP)
• Linux (also available in distribution packages)
• macOS
• IBM AIX
• FreeBSD
• OpenBSD
• Solaris

It is also possible to download legacy Zabbix agent binaries for NetBSD and HP-UX, and those are compatible with current Zabbix server/proxy version.

Agent on UNIX-like systems

Zabbix agent on UNIX-like systems is run on the host being monitored.

Installation

See the package installation section for instructions on how to install Zabbix agent as package.

Alternatively see instructions for manual installation if you do not want to use packages.

If installed as package

Zabbix agent runs as a daemon process. The agent can be started by executing:

service zabbix-agent start

This will work on most of GNU/Linux systems. On other systems you may need to run:

/etc/init.d/zabbix-agent start

Similarly, for stopping/restarting/viewing status of Zabbix agent, use the following commands:

service zabbix-agent stop
       service zabbix-agent restart
       service zabbix-agent status

Start up manually

If the above does not work you have to start it manually. Find the path to the zabbix_agentd binary and execute:

zabbix_agentd

Agent on Windows systems

Zabbix agent on Windows runs as a Windows service.

Installation

Zabbix agent can be installed on Windows using one of the following methods:

• Pre-compiled Zabbix agent binaries - download the Zabbix agent MSI installer package and follow the instructions on the Windows agent installation from MSI page.
• Zabbix sources - download the source files and follow the instructions on the Building Zabbix agent on Windows page.

See the Zabbix agent on Microsoft Windows page for additional details on installing Zabbix agent (from a ZIP archive) as a Windows service.

Options

It is possible to run multiple instances of the agent on a host. A single instance can use the default configuration file or a configuration file specified in the command line. In case of multiple instances each agent instance must have its own configuration file (one of the instances can use the default configuration file).

The following command-line parameters can be used with Zabbix agent:

Specific examples of using command-line parameters:

• printing all built-in agent items with values
• testing a user parameter with "mysql.ping" key defined in the specified configuration file
• installing a "Zabbix Agent" service for Windows using the default path to configuration file C:\Program Files\Zabbix Agent\zabbix_agentd.conf
• installing a "Zabbix Agent [Hostname]" service for Windows using the configuration file zabbix_agentd.conf located in the same folder as agent executable and making the service name unique by extending it by Hostname value from the config file
• modifying the startup type of an installed "Zabbix Agent" service for Windows using the configuration file zabbix_agentd.conf located in the same folder as agent executable

zabbix_agentd --print
       zabbix_agentd -t "mysql.ping" -c /etc/zabbix/zabbix_agentd.conf
       zabbix_agentd.exe -i
       zabbix_agentd.exe -i -m -c zabbix_agentd.conf
       zabbix_agentd.exe -c zabbix_agentd.conf -S delayed

Runtime control

With runtime control options you may change the log level of agent processes.

Examples:

• increasing log level of all processes
• increasing log level of the third listener process
• increasing log level of process with PID 1234
• decreasing log level of all active check processes

zabbix_agentd -R log_level_increase
       zabbix_agentd -R log_level_increase=listener,3
       zabbix_agentd -R log_level_increase=1234
       zabbix_agentd -R log_level_decrease="active checks"

Agent process types

• active checks - process for performing active checks
• collector - process for data collection
• listener - process for listening to passive checks

The agent log file can be used to observe these process types.

Process user

Zabbix agent on UNIX is designed to run as a non-root user. It will run as whatever non-root user it is started as. So you can run agent as any non-root user without any issues.

If you will try to run it as 'root', it will switch to a hardcoded 'zabbix' user, which must be present on your system. You can only run agent as 'root' if you modify the 'AllowRoot' parameter in the agent configuration file accordingly.

Configuration file

For details on configuring Zabbix agent see the configuration file options for zabbix_agentd or Windows agent.

Locale

Note that the agent requires a UTF-8 locale so that some textual agent items can return the expected content. Most modern Unix-like systems have a UTF-8 locale as default, however, there are some systems where that may need to be set specifically.

Exit code

Zabbix agent returns 0 in case of successful exit and 1 in case of failure.