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Fluent Bit📜

Overview📜

This package contains an extensible and configurable installation of Fluent Bit based on the upstream chart provided by Fluent.

Fluent Bit📜

Fluent Bit is an open-source log processor and forwarder. It collects logs and metrics from multiple sources, enriches them with filters, and sends them to configured destinations. Its small footprint and pluggable architecture make it well suited to Kubernetes.

Fluent Bit is a CNCF (Cloud Native Computing Foundation) subproject under the umbrella of Fluentd.

How it works📜

Fluent Bit mounts /var/log from each node and tails Kubernetes container logs matching /var/log/containers/*.log. The package also configures a systemd input for kubelet.service. Records are sent to the output or outputs configured through the package values. A hostPath-backed storage buffer is enabled for production workloads. No output is defined directly in the package’s upstream configuration; Big Bang supplies outputs according to the enabled logging stack:

  • When Loki is enabled, Big Bang configures the Loki output and disables the default Elasticsearch-specific output.
  • When Logging is enabled, Big Bang configures the Elasticsearch (es) output.
  • The additionalOutputs values provide package-specific helpers for other destinations.

k3d CI compatibility📜

The package retains its existing DaemonSet volume defaults, including /var/lib/docker/containers and /etc/machine-id, to avoid changing behavior for current consumers. Big Bang’s exact-head CI jobs create k3d clusters, whose nodes do not run kubelet as a systemd service. The umbrella tests/test-values.yaml therefore replaces upstream.config.inputs with only the Kubernetes container-tail input and replaces both upstream.daemonSetVolumes and upstream.daemonSetVolumeMounts with only the read-only /var/log mount.

This is a k3d-specific CI override, not a package default. It preserves collection of pod standard output and standard error while omitting the systemd input and its machine-ID dependency. Deployments that need host journal logs should retain or provide node-appropriate journal inputs, volumes, mounts, and security settings.

Review the Big Bang logging architecture documentation for more information about Fluent Bit’s role within Big Bang.