14 Plugins

Overview

Plugins provide an option to extend the monitoring capabilities of Zabbix. Plugins are written in the Go programming language and are supported by Zabbix agent 2 only.

Plugins provide an alternative to loadable modules (written in C), and other methods for extending Zabbix functionality, such as user parameters (agent metrics), external checks (agent-less monitoring), and system.run[] Zabbix agent item.

The following features are specific to agent 2 and its plugins:

• single configuration file (all plugin configuration parameters are located in the same file as parameters of the agent itself);
• task queue management with respect to schedule and task concurrency;
• plugin-level timeouts.

Configuring plugins

Common configuration principles and best practices are described in this section.

All plugins are configured using Plugins.* parameter of the Zabbix agent 2 configuration file. Unlike other agent parameters, it is not a key/value type of parameter. It is a separate section where specific parameters of the plugin can be described. Each parameter should have the following structure:

Plugins.<PluginName>.<Parameter>=<Value>

Parameter names should adhere to the following requirements:

• it is recommended to capitalize the names of your plugins;
• the parameter should be capitalized;
• special characters are not allowed;
• nesting isn’t limited by a maximum level;
• the number of parameters is not limited.

Named sessions

Named sessions represent an additional level of plugin parameters and can be used to define separate sets of authentication parameters for each of the instances being monitored. Each named session parameter should have the following structure:

Plugins.<PluginName>.<SessionName>.<Parameter>=<Value>

A session name can be used as a connString item key parameter instead of specifying a URI, username, and password separately. In item keys, the first parameter can be either a connString or a Uri. If the first key parameter matches a session name specified in the configuration file, the check will be executed using named session parameters. If the first key parameter doesn’t match any session name, it will be treated as a Uri.

Note, that:

• when providing a connString (session name) in key parameters, key parameters for username and password must be empty;
• passing embedded URI credentials is not supported, consider using named sessions instead;
• in case an authentication parameter is not specified for the named session, a hardcoded default value will be used.

The list of available named session parameters depends on the plugin, see Zabbix agent 2 (UNIX) / Zabbix agent 2 (Windows) for details.

Example: Monitoring of two instances “MySQL1” and “MySQL2” can be configured in the following way:

Plugins.Mysql.Sessions.MySQL1.Uri=tcp://127.0.0.1:3306
       Plugins.Mysql.Sessions.MySQL1.User=<UsernameForMySQL1>
       Plugins.Mysql.Sessions.MySQL1.Password=<PasswordForMySQL1>    
       Plugins.Mysql.Sessions.MySQL2.Uri=tcp://127.0.0.1:3307   
       Plugins.Mysql.Sessions.MySQL2.User=<UsernameForMySQL2>
       Plugins.Mysql.Sessions.MySQL2.Password=<PasswordForMySQL2>

Now, these names may be used as connStrings in keys instead of URIs:

mysql.ping[MySQL1]
       mysql.ping[MySQL2]

Hardcoded defaults

If a parameter required for authentication is not provided in an item key or in the named session parameters, the plugin will use a hardcoded default value.

Connections

Some plugins support gathering metrics from multiple instances simultaneously. Both local and remote instances can be monitored. TCP and Unix-socket connections are supported.

It is recommended to configure plugins to keep connections to instances in an open state. The benefits are reduced network congestion, latency, and CPU and memory usage due to the lower number of connections. The client library takes care of this.

Time period for which unused connections should remain open can be determined by Plugins.<PluginName>.KeepAlive parameter.
Example: Plugins.Memcached.KeepAlive

Plugins supplied out-of-the-box

All metrics supported by Zabbix agent 2 are collected by plugins. The following plugins for Zabbix agent 2 are available out-of-the-box: