Rule Conditions

Every rule has a condition section that controls which hosts the rule applies to. You can match by hostname or by attribute, with a wide range of comparison operators.

Set the condition mode at the top of the rule to control how multiple conditions are combined:

• ANY — one matching condition is enough for the rule to match
• ALL — every condition must match
• Anyway — the rule always matches, regardless of conditions

Condition Types

All string-based conditions are case-insensitive, except regex.

Condition Type	Description	Case Sensitive
equal	Attribute exactly equals the given value	No
in	Given string is contained in the attribute value (works with strings and lists)	No
not_in	Given string is NOT contained in the attribute value (works with strings and lists)	No
in_list	Attribute value is found in your comma-separated list	No
string_in_list	Your string is found in the attribute's Python/comma-separated list	No
swith	Attribute starts with the given string	No
ewith	Attribute ends with the given string	No
regex	Attribute matches the given regular expression	Yes
bool	Attribute matches a boolean True/False value	—
ignore	Always matches (negate to check that attribute does not exist)	—

Every condition can be negated with the corresponding negate checkbox, which inverts the match result.

Match FAQ

Match if an attribute does NOT exist on a host

• Set Tag Match to Match All (*)
• Set Tag to the attribute name you want to check
• Enable the Tag Match Negate checkbox
• The value match does not matter

Match if an attribute is an empty string

Note

To prevent empty attributes from being imported at all, set LABELS_IMPORT_EMPTY=False in local_config.py.

• Set Tag Match to the attribute name
• Set Value Match to String Equal
• Leave the value field empty (that is the empty string)

Match a key in a dictionary

If an attribute contains a dictionary (e.g. {"status": "active", "env": "prod"}), you can match against a specific key using the in condition type.

The in condition checks whether your string is contained in the string representation of the attribute value. For structured data, use a Jinja rewrite rule first to extract the key into a flat attribute, then match against that.

Match using regex with capture groups

When using regex, you can reference the first matching value in rewrite rules via the special placeholder {{FIRST_MATCHING_VALUE}}. See Rewrite Attributes for details.

Use in_list vs string_in_list

These two types are often confused:

• in_list: Your rule provides the list. The host attribute is checked against whether it appears in your list. Example: host has os=windows, your list is windows,linux,macos → matches.
• string_in_list: The host attribute is the list. Your rule provides the string to look for inside it. Example: host has services=dns,dhcp,ntp, your string is dns → matches.