14 Plugins

Overview

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

A typical plugin parameter has the following structure:

• Plugins.<PluginName>.<SessionName>.<Parameter>=<Value> used for defining separate sets of parameters for different monitoring targets via named sessions.

Additionally, there are two specific groups of parameters:

• Plugins.<PluginName>.Default.<Parameter>=<Value> used for defining default parameter values.

• Plugins.<PluginName>.<SessionName>.<Parameter>=<Value> used for defining separate sets of parameters for different monitoring targets via named sessions.

All 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.

Default values

Since Zabbix 5.0.35, you can set default values for the connection-related parameters (URI, username, password, etc.) in the configuration file in the format:

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

For example, Plugins.Mysql.Default.Username=zabbix, Plugins.MongoDB.Default.Uri=tcp://127.0.0.1:27017, etc.

If a value for such parameter is not provided in an item key or in the named session parameters, the plugin will use the default value. If a default parameter is also undefined, hardcoded defaults will be used.

Named sessions

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

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

A session name can be used as a connString item key parameter instead of specifying a URI, username, and/or password separately.

In item keys, the first parameter can be either a connString or a URI. If the first key parameter doesn't match any session name, it will be treated as a URI. Note that embedding credentials into a URI is not supported, use named session parameters instead.

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

In Zabbix versions before 5.0.34, when providing a connString (session name) in key parameters, item key parameters for username and password must be empty. The values will be taken from the session parameters. If an authentication parameter is not specified for the named session, a hardcoded default value will be used.

Since Zabbix 5.0.34, it is possible to override session parameters by specifying new values in the item key parameters (see example).

Since Zabbix 5.0.35, if a parameter is not defined for the named session, Zabbix agent 2 will use the value defined in the default plugin parameter.

Parameter priority

Since version 5.0.34, Zabbix agent 2 plugins search for connection-related parameter values in the following order:

1. The first item key parameter is compared to session names. If no match is found it is treated as an actual value; in this case, step 3 will be skipped. If a match is found, the parameter value (usually, a URI) must be defined in the named session.
2. Other parameters will be taken from the item key if defined.
3. If an item key parameter (for example, password) is empty, plugin will look for the corresponding named session parameter.
4. If the session parameter is also not specified, the value defined in the corresponding default parameter will be used.
5. If all else fails, the plugin will use the hardcoded default value.

Example 1

Monitoring of two instances “MySQL1” and “MySQL2”.

Configuration parameters:

Plugins.Mysql.Sessions.MySQL1.Uri=tcp://127.0.0.1:3306
       Plugins.Mysql.Sessions.MySQL1.User=mysql1_user
       Plugins.Mysql.Sessions.MySQL1.Password=unique_password
       Plugins.Mysql.Sessions.MySQL2.Uri=tcp://192.0.2.0:3306
       Plugins.Mysql.Sessions.MySQL2.User=mysql2_user
       Plugins.Mysql.Sessions.MySQL2.Password=different_password

Item keys: mysql.ping[MySQL1], mysql.ping[MySQL2]

Example 2

Providing some of the parameters in the item key (supported since Zabbix 5.0.34).

Configuration parameters:

Plugins.Postgres.Sessions.Session1.Uri=tcp://192.0.2.234:5432
       Plugins.Postgres.Sessions.Session1.User=old_username
       Plugins.Postgres.Sessions.Session1.Password=session_password

Item key: pgsql.ping[session1,new_username,,postgres]

As a result of this configuration, the agent will connect to PostgreSQL using the following parameters:

• URI from session parameter: 192.0.2.234:5432
• Username from the item key: new_username
• Password from session parameter (since it is omitted in the item key): session_password
• Database name from the item key: postgres

Example 3

Collecting a metric using default configuration parameters.

Configuration parameters:

Plugins.Postgres.Default.Uri=tcp://192.0.2.234:5432
       Plugins.Postgres.Default.User=zabbix
       Plugins.Postgres.Default.Password=password

Item key: pgsql.ping[,,,postgres]

As a result of this configuration, the agent will connect to PostgreSQL using the parameters:

• Default URI: 192.0.2.234:5432
• Default username: zabbix
• Default password: password
• Database name from the item key: postgres

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.

Plugins supplied out-of-the-box

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