Fluentd vs Grafana Loki

Fluentd is a free, open-source data collector for creating a unified logging layer. It uses JSON to handle log collection, filtering, buffering, and output across sources and destinations. More than 500 community plugins connect it to data sources and outputs, including Elasticsearch and Kibana, Splunk, AWS S3, Kafka, BigQuery, Datadog, and OpenTelemetry. It supports memory and file buffering, failover, and high availability to help prevent data loss between nodes. The project reports that a vanilla instance uses 30–40 MB of memory and can process 13,000 events per second per core. Fluentd v1 runs on Linux, Mac OSX, and Windows; community distributions also include Docker images, a Kubernetes DaemonSet, and Ruby gems. It is self-hosted, and its components are available under the Apache 2 License. The project lists community help and commercial support from companies offering enterprise services. The homepage notes vulnerabilities patched in Fluentd v1.19.3 and advises updating fluent-package to v6.0.4.

Grafana Loki is a free, AGPLv3-licensed log aggregation system for storing and querying application and infrastructure logs. It can be self-hosted on Linux or accessed through Grafana Cloud Logs plans, with API support and live log tailing. Loki scales horizontally, supports high availability and multiple tenants, and indexes labels instead of log-line contents. LogQL provides queries in Grafana or the LogCLI command-line tool. Grafana describes object-storage support for high-throughput, durable, petabyte-scale retention. Loki can evaluate alerting rules on incoming logs and send results to Prometheus Alertmanager, with native integrations for Prometheus, Grafana, and Kubernetes. Documented ingestion options include Grafana Alloy, OpenTelemetry, Kubernetes Monitoring Helm, Docker, Fluent Bit, Fluentd, and Logstash. Installation methods include Helm, Tanka, Docker, Docker Compose, local installation, and source builds. Cloud plans range from free to paid Pro and Enterprise options.