Fluentd is an open-source data collector specifically designed with a flexible plug-in architecture. This architecture allows it to unify data collection and consumption. It uses a wide variety of input plug-ins to collect data from numerous sources (e.g., application log files, systemd journals, TCP sockets) and output plug-ins to send the collected data to multiple destinations (e.g., Elasticsearch, Kafka, cloud storage). This extensibility is a core feature of Fluentd and makes it the standard log forwarding agent in the Red Hat OpenShift Container Platform logging stack, which is a foundational component for many IBM Cloud Paks.

A. Journald: This is a component of systemd that collects and stores log data on a single Linux host; it is not primarily known for a distributed, plug-in-based architecture for multiple destinations.

B. Rsyslog Sidecar: This describes a deployment pattern (a sidecar container) for the rsyslog service, not a type of log collector defined by its plug-in model.

D. Audit Container: This describes the function of a container (collecting audit logs), not a specific log collector technology known for its extensive input/output plug-in ecosystem.

1. Red Hat OpenShift Container Platform 4.10 Documentation

"About OpenShift Logging"

Section 1.1. "Log collection". The documentation states

"Fluentd is deployed to each node in the OpenShift Container Platform cluster to collect all node and container logs... The Fluentd agent gets the logs and forwards them to the log store." This highlights its role as a collector and forwarder in the platform IBM Cloud Paks are built upon.

2. Fluentd Official Documentation

"Architecture". The documentation explicitly states: "Fluentd has a flexible plugin system that allows its community to extend its functionality. Its 500+ community-contributed plugins connect dozens of data sources and data outputs." This directly confirms the input/output plug-in model described in the question.

3. IBM Cloud Pak for Business Automation 21.0.3 Documentation

"Monitoring health"

"Reference for monitoring services". The documentation details that logging relies on the components provided by the OpenShift Container Platform

which includes the EFK (Elasticsearch

Fluentd

and Kibana) stack. This confirms the use of Fluentd within the IBM Cloud Pak ecosystem.