The EFK Stack integrates three tools—Elasticsearch, Fluentd, and Kibana—to collect, store, and visualize metric data. Elasticsearch is a search engine that ingests and stores data in a central repository, while Fluentd collects data from the logs of Kubernetes pods and routes it to Elasticsearch. Kibana is a plugin for Elasticsearch that functions as the UI for the EFK Stack, enabling the visualization of the logs and metrics in the form of custom dashboards.