Mesos is an open source cluster manager that allocates resources such as CPU and RAM for distributed applications like Spark, Hadoop, and Kafka. It was built to run high-scale applications and can be used with container technologies like Docker. Datadog has integrated Mesos into its monitoring platform, allowing users to see metrics from all nodes in the cluster, including resource utilization, task execution, and application performance. This integration enables comprehensive dashboards for each service, providing insights into scaling events, resource allocation, and more. With this integration, users can monitor their entire cluster in one place, eliminating the need for ad hoc command line queries or separate web UIs for individual technologies.