2 User macros

Overview

User macros are supported in Zabbix for greater flexibility, in addition to the macros supported out-of-the-box.

User macros can be defined on global, template and host level. These macros have a special syntax:

{$MACRO}

Zabbix resolves macros according to the following precedence:

1. host level macros (checked first)
2. macros defined for first level templates of the host (i.e., templates linked directly to the host), sorted by template ID
3. macros defined for second level templates of the host, sorted by template ID
4. macros defined for third level templates of the host, sorted by template ID, etc.
5. global macros (checked last)

In other words, if a macro does not exist for a host, Zabbix will try to find it in the host templates of increasing depth. If still not found, a global macro will be used, if exists.

If Zabbix is unable to find a macro, the macro will not be resolved.

User macros can be used in:

• item name
• item key parameter
• item update intervals and flexible intervals
• trigger name and description
• trigger expression parameters and constants (see examples)
• many other locations - see the full list

Common use cases of global and host macros

• use a global macro in several locations; then change the macro value and apply configuration changes to all locations with one click
• take advantage of templates with host-specific attributes: passwords, port numbers, file names, regular expressions, etc.

Configuration

To define user macros, go to the corresponding location in the frontend:

• for global macros, visit Administration → General → Macros
• for host and template level macros, open host or template properties and look for the Macros tab

A user macro has the following attributes:

Parameter	Description
Macro	Macro name. The name must be wrapped in curly brackets and start with a dollar sign. Example: {$FRONTEND_URL}. The following characters are allowed in the macro names: A-Z (uppercase only) , 0-9 , _ , .
Value	Macro value. Three value types are supported: Text (default) - plain-text value Secret text - the value is masked with asterisks, which could be useful to protect sensitive information such as passwords or shared keys. Vault secret - the value contains a reference path (as 'path:key', for example “secret/zabbix:password”) to a Vault secret Note that while the value of a secret macro is hidden from sight, the value can be revealed through the use in items. For example, in an external script an 'echo' statement referencing a secret macro may be used to reveal the macro value to the frontend because Zabbix server has access to the real macro value. To select the value type click on the button at the end of the value input field: icon indicates a text macro; icon indicates a secret text macro. Upon hovering, the value field transforms into a button, which allows to enter a new value of the macro (to exit without saving a new value, click the backwards arrow (). icon indicates a secret Vault macro. Maximum length of a user macro value is 2048 characters (255 characters in versions before 5.2.0).
Description	Text field used to provide more information about this macro.

Examples

Example 1

Use of host-level macro in the "Status of SSH daemon" item key:

net.tcp.service[ssh,,{$SSH_PORT}]

This item can be assigned to multiple hosts, providing that the value of {$SSH_PORT} is defined on those hosts.

Example 2

Use of host-level macro in the "CPU load is too high" trigger:

last(/ca_001/system.cpu.load[,avg1])>{$MAX_CPULOAD}

Such a trigger would be created on the template, not edited in individual hosts.

Example 3

Use of two macros in the "CPU load is too high" trigger:

min(/ca_001/system.cpu.load[,avg1],{$CPULOAD_PERIOD})>{$MAX_CPULOAD}

Note that a macro can be used as a parameter of trigger function, in this example function min().

Example 4

Synchronize the agent unavailability condition with the item update interval:

• define {$INTERVAL} macro and use it in the item update interval;
• use {$INTERVAL} as parameter of the agent unavailability trigger:

nodata(/ca_001/agent.ping,{$INTERVAL})=1

Example 5

Centralize configuration of working hours:

• create a global {$WORKING_HOURS} macro equal to 1-5,09:00-18:00;
• use it in the Working time field in Administration → General → GUI;
• use it in the When active field in Administration → User → Media;
• use it to set up more frequent item polling during working hours:

• use it in the Time period action condition;
• adjust the working time in Administration → General → Macros, if needed.

Example 6

Use host prototype macro to configure items for discovered hosts:

• on a host prototype define user macro {$SNMPVALUE} with {#SNMPVALUE} low-level discovery macro as a value:

• assign Generic SNMPv2 template to the host prototype;
• use {$SNMPVALUE} in the SNMP OID field of Generic SNMPv2 template items.

User macro context

See user macros with context.