3 Agent 2

3 Agent 2

Overview

Zabbix agent 2 is a new generation of Zabbix agent and may be used in place of Zabbix agent. Zabbix agent 2 has been developed to:

reduce the number of TCP connections
provide improved concurrency of checks
be easily extendible with plugins. A plugin should be able to:
- provide trivial checks consisting of only a few simple lines of code
- provide complex checks consisting of long-running scripts and standalone data gathering with periodic sending back of the data
be a drop-in replacement for Zabbix agent (in that it supports all the previous functionality)

Agent 2 is written in Go programming language (with some C code of Zabbix agent reused). A configured Go environment with a currently supported Go version is required for building Zabbix agent 2.

Agent 2 does not have built-in daemonization support on Linux; it can be run as a Windows service.

Passive and active checks

Passive checks work similarly to Zabbix agent. Active checks support scheduled/flexible intervals and check concurrency within one active server.

By default, after a restart, Zabbix agent 2 will schedule the first data collection for active checks at a conditionally random time within the item’s update interval to prevent spikes in resource usage. To perform active checks that do not have Scheduling update interval immediately after the agent restart, set ForceActiveChecksOnStart parameter (global-level) or Plugins.<Plugin name>.System.ForceActiveChecksOnStart (affects only specific plugin checks) in the configuration file. Plugin-level parameter, if set, will override the global parameter. Forcing active checks on start is supported since Zabbix 6.0.2.

Check concurrency

Checks from different plugins can be executed concurrently. The number of concurrent checks within one plugin is limited by the plugin capacity setting. Each plugin may have a hardcoded capacity setting (100 being default) that can be lowered using the Plugins.<PluginName>.System.Capacity=N setting in the Plugins configuration parameter. Former name of this parameter Plugins.<PluginName>.Capacity is still supported, but has been deprecated in Zabbix 6.0.

Supported platforms

Zabbix agent 2 is supported on the following platforms:

Windows (all desktop and server versions since XP; also available as a pre-compiled binary)
Linux (also available in distribution packages)

Installation

Zabbix agent 2 is available in pre-compiled Zabbix packages. To compile Zabbix agent 2 from sources you have to specify the --enable-agent2 configure option.

Options

The following command line parameters can be used with Zabbix agent 2:

Parameter	Description
-c —config <config-file>	Path to the configuration file. You may use this option to specify a configuration file that is not the default one. On UNIX, default is /usr/local/etc/zabbix_agent2.conf or as set by compile-time variables —sysconfdir or —prefix
-f —foreground	Run Zabbix agent in foreground (default: true).
-p —print	Print known items and exit. Note: To return user parameter results as well, you must specify the configuration file (if it is not in the default location).
-t —test <item key>	Test specified item and exit. Note: To return user parameter results as well, you must specify the configuration file (if it is not in the default location).
-h —help	Print help information and exit.
-v —verbose	Print debugging information. Use this option with -p and -t options.
-V —version	Print agent version and license information.
-R —runtime-control <option>	Perform administrative functions. See runtime control.

Specific examples of using command line parameters:

print all built-in agent items with values
test a user parameter with “mysql.ping” key defined in the specified configuration file

shell> zabbix_agent2 —print shell> zabbix_agent2 -t “mysql.ping” -c /etc/zabbix/zabbix_agentd.conf

Runtime control

Runtime control provides some options for remote control.

Option	Description
log_level_increase	Increase log level.
log_level_decrease	Decrease log level.
metrics	List available metrics.
version	Display agent version.
userparameter_reload	Reload user parameters from the current configuration file. Note that UserParameter is the only agent configuration option that will be reloaded.
help	Display help information on runtime control.

Examples:

increasing log level for agent 2
print runtime control options

shell> zabbix_agent2 -R log_level_increase
       shell> zabbix_agent2 -R help

Configuration file

The configuration parameters of agent 2 are mostly compatible with Zabbix agent with some exceptions.

New parameters	Description
ControlSocket	The runtime control socket path. Agent 2 uses a control socket for runtime commands.
EnablePersistentBuffer, PersistentBufferFile, PersistentBufferPeriod	These parameters are used to configure persistent storage on agent 2 for active items.
ForceActiveChecksOnStart	Determines whether the agent should perform active checks immediately after restart or spread evenly over time.
Plugins	Plugins may have their own parameters, in the format `Plugins.<Plugin name>.<Parameter>=<value>`. A common plugin parameter is System.Capacity, setting the limit of checks that can be executed at the same time.
StatusPort	The port agent 2 will be listening on for HTTP status request and display of a list of configured plugins and some internal parameters
Dropped parameters	Description
AllowRoot, User	Not supported because daemonization is not supported.
LoadModule, LoadModulePath	Loadable modules are not supported.
StartAgents	This parameter was used in Zabbix agent to increase passive check concurrency or disable them. In Agent 2, the concurrency is configured at a plugin level and can be limited by a capacity setting. Whereas disabling passive checks is not currently supported.
HostInterface, HostInterfaceItem	Not yet supported.

For more details see the configuration file options for zabbix_agent2.

Exit codes

Starting from version 4.4.8 Zabbix agent 2 can also be compiled with older OpenSSL versions (1.0.1, 1.0.2).

In this case Zabbix provides mutexes for locking in OpenSSL. If a mutex lock or unlock fails then an error message is printed to the standard error stream (STDERR) and Agent 2 exits with return code 2 or 3, respectively.