Mesos is a cluster manager that provides efficient resource isolation and sharing across distributed applications running on a shared pool of nodes. It provides APIs for resource management and scheduling and can run applications like Hadoop, Spark, and Kafka across large compute clusters. Mesos was created at Berkeley and adopted by companies like Twitter, Airbnb, and Hubspot to improve resource utilization, allow dynamic scaling of services, and reduce the operational complexity of managing large fleets of servers. Mesos also integrates with Docker and Kubernetes to enable containerized workloads and services to be deployed and orchestrated on Mesos clusters.