Chronos is a replacement for cron. It is a distributed and fault-tolerant scheduler that runs on top of Apache Mesos that can be used for job orchestration. It supports custom Mesos executors as well as the default command executor. Thus by default, Chronos executes sh (on most systems bash) scripts. Chronos can be used to interact with systems such as Hadoop (incl. EMR), even if the Mesos agents on which execution happens do not have Hadoop installed. Included wrapper scripts allow transfering files and executing them on a remote machine in the background and using asynchronous callbacks to notify Chronos of job completion or failures. Chronos is also natively able to schedule jobs that run inside Docker containers.