Fluent Bit

In the cloud-native world, the assumption is that all logging follows the standard Kubernetes architecture: containers log to standard output. From there, logs can be picked up by a myriad of tools to feed into a plethora of different pipelines.

By default, Couchbase Server does not follow this cloud-native standard, and instead writes logs to various log files held on an optional volume. However, the Couchbase Autonomous Operator can optionally manage a sidecar container, built on the Fluent Bit technology, that can process and forward Couchbase logs to any number of locations, including standard output.

The sidecar approach used by the Couchbase-supplied Fluent Bit container is the same one followed by the Couchbase Prometheus Exporter, and is completely optional. Fluent Bit handles basic parsing of the logs and supports any end point provided by Fluent Bit. A default configuration is provided that sends all logs to the standard output stream of the container, but this is fully customizable to integrate with user-provided tooling.

Fluent Bit log forwarding is managed by the Couchbase Autonomous Operator. Log forwarding can be enabled via the CouchbaseCluster custom resource specification (it is disabled by default). When enabled, the Autonomous Operator automatically deploys the Couchbase-supplied fluent-bit container image, along with a default log forwarding configuration in the form of a Kubernetes Secret that gets consumed by the logging sidecar container.