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Rewrite Attributes

Different target systems have different requirements for attribute names and values. Rewrite rules let you rename, transform, or derive new attributes for each module independently.

Go to the Rewrite Attributes section of the module you want to configure (for example, Modules → Checkmk → Rewrite Attributes).

Example: An import from CSV gives you csv__ipaddress. With a rewrite rule, you can rename it to ipaddress before it is exported to Checkmk.

Operations for Attribute Names

Function Description
Don't Use Keep the original attribute name. Use with a new attribute name to create a copy.
Overwrite with fixed String The value in New Attribute Name replaces the original attribute name
Overwrite with Jinja Template Build the new attribute name with Jinja — access all host attributes and {{HOSTNAME}}
Convert List of Strings Create multiple new attributes from a list — one attribute per list item

Convert List of Strings

This function creates multiple new attributes from a list, one attribute per list item. The list can come from an existing attribute or be built with Jinja.

Set Old Attribute Name to the source attribute. Use {{result}} in New Attribute Name to reference the current list item.

If the attribute already contains a Python list such as ['one_service', 'another_service'], it works directly. If not, use Jinja to produce a list:

[{% for label in get_list(result) %}'my_prefix/{{label}}',{% endfor %}]

Note the surrounding brackets and the quoted values with commas — this builds a string that looks like a Python list.

Set Value to To String and the New Value to yes, and you get:

one_service: yes
another_service: yes

Operations for Attribute Values

Function Description
To String Set the attribute value to a fixed string
With Split Split the value using SEPARATOR:INDEX syntax, e.g. /:0
With Jinja Template Build the value with Jinja — access all host attributes and {{HOSTNAME}}

Split

Provide a pattern as SEPARATOR:INDEX. The value is split at the separator, and the item at the given index is used as the new value.

Example: /:0

Applied to 127.0.0.1/24: splits at / → ['127.0.0.1', '24'] → index 0 → 127.0.0.1

Creating New Attributes

If you specify an attribute name in Old Attribute Name that does not exist on the host, it will be created as a new attribute. All value operations can be used, so you can compose a new attribute from multiple existing ones using Jinja.

Special Jinja Variables

When using conditions with regex, swith, ewith, and similar types, you may not know in advance which attribute triggered the match. Two special placeholders are available in Jinja value rewrites:

  • {{FIRST_MATCHING_TAG}} — the name of the attribute that caused the condition to match
  • {{FIRST_MATCHING_VALUE}} — the value of that attribute