Table of Contents
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 Windows 10/Server 2016) - available as a pre-compiled binary or in Zabbix sources
- Linux - available in distribution packages or Zabbix sources
Installation
To install Zabbix agent 2, the following options are available:
Windows:
- from a pre-compiled binary - download the binary and follow the instructions on the Windows agent installation from MSI page
- from sources - see Building Zabbix agent 2 on Windows
Linux:
- from distribution packages - follow the instructions on the Zabbix packages page, available by choosing your distribution and the Agent 2 component
- from sources - see Installation from sources; note that you must configure the sources by specifying the
--enable-agent2configuration option
Zabbix agent 2 monitoring capabilities can be extended with plugins. While built-in plugins are available out-of-the-box, loadable plugins must be installed separately. For more information, see Plugins.
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 values of the UserParameter and Include options from the current configuration file. |
| help | Display help information on runtime control. |
Examples:
- increasing log level for agent 2
- print runtime control options
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.