Config file format

Beats config files are based on YAML, a file format that is easier to read and write than other common data formats like XML or JSON. Config files must be encoded in UTF-8.

In beats all YAML files start with a dictionary, an unordered collection of name/value pairs. In addition to dictionaries, YAML also supports lists, numbers, strings, and many other data types. All members of the same list or dictionary must have the same indentation level.

Dictionaries are represented by simple key: value pairs all having the same indentation level. The colon after key must be followed by a space.

name: John Doe
age: 34
country: Canada

Lists are introduced by dashes - . All list members will be lines beginning with - at the same indentation level.

- Red
- Green
- Blue

Lists and dictionaries are used in beats to build structured configurations.

filebeat:
  inputs:
    - type: log
      paths:
        - /var/log/*.log
      multiline:
        pattern: '^['
        match: after

Lists and dictionaries can also be represented in abbreviated form. Abbreviated form is somewhat similar to JSON using {} for dictionaries and [] for lists:

person: {name: "John Doe", age: 34, country: "Canada"}
colors: ["Red", "Green", "Blue"]

The following topics provide more detail to help you understand and work with config files in YAML:

• Namespacing
• Config file data types
• Environment variables
• Reference variables
• Config file ownership and permissions
• Command line arguments
• YAML tips and gotchas