Classic mode

Fluent Bit classic mode configuration will be deprecated at the end of 2026.

Classic mode is a custom configuration model for Fluent Bit. It's more limited than the YAML configuration mode, and doesn't have the more extensive feature support the YAML configuration has. Classic mode basic design only supports grouping sections with key-value pairs and lacks the ability to handle sub-sections or complex data structures like lists.

Learn more about classic mode:

• Format and schema

• Variables

• Configuration file

• Commands

• Upstream servers

• Record accessor syntax