fluent-bit

What is fluent-bit?

The fluent-bit image runs Fluent Bit, a lightweight and high-performance log processor and forwarder. It’s part of the Fluentd ecosystem and is designed for collecting, parsing, filtering, and shipping logs from various sources to different destinations.

Fluent Bit is optimized for minimal resource usage and is particularly well-suited for containerized and edge environments. It supports multiple input and output plugins, enabling it to forward logs to services such as Elasticsearch, OpenSearch, Loki, Kafka, Splunk, Amazon CloudWatch, and more.

This image is widely used in Kubernetes as a DaemonSet to collect logs from all nodes and containers, as well as in standalone Docker deployments for targeted log forwarding.

How to use this image

Fluent Bit runs using a configuration file or command-line options that define the pipeline from input to output.

Run with a local configuration file:

‍<code>docker run --rm -v $(pwd)/fluent-bit.conf:/fluent-bit/etc/fluent-bit.conf \  -p 2020:2020 fluent/fluent-bit:2.2</code>

Example configuration (fluent-bit.conf):

<code>iniCopyEdit[INPUT]    Name tail    Path /var/log/*.log    Tag  host.*[OUTPUT]    Name stdout    Match *</code>

Run in Kubernetes as a DaemonSet (Helm example):

<code>helm repo add fluent https://fluent.github.io/helm-chartshelm install fluent-bit fluent/fluent-bit \  --set backend.type=es \  --set backend.es.host=elasticsearch.default.svc</code>

Ports and endpoints:

• 2020 – HTTP server for health checks and metrics
• 2021 – Optional API endpoint for runtime configuration (when enabled)

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Image variants

Published under fluent/fluent-bit, the image is available in multiple variants:

fluent/fluent-bit:latest

Latest stable release with default plugins.Use for dev or testing environments.

fluent/fluent-bit:<version>

Tagged by version (e.g. 2.2.0, 1.9.10).

Recommended for production to avoid unplanned upgrades.

fluent/fluent-bit:<version>-debug

Includes debugging tools and verbose logging for troubleshooting.

fluent/fluent-bit:<version>-arm64

Architecture-specific build for ARM64-based systems.Fluent Bit images are built on a minimal base with only the required dependencies for log processing.