Folks, The master stores a cache of metadata about recently completed tasks; for example, this information can be accessed via the "/tasks" HTTP endpoint or the "GET_TASKS" call in the new Operator API.
The master currently stores this metadata using a list; this means that duplicate task IDs are permitted. We're considering [1] changing this to use a hashmap instead. Using a hashmap would mean that duplicate task IDs would be discarded: if two completed tasks have the same task ID, only the metadata for the most recently completed task would be retained by the master. If this behavior change would cause problems for your framework or other software that relies on Mesos, please let me know. (Note that if you do have two completed tasks with the same ID, you'd need an unambiguous way to tell them apart. As a recommendation, I would strongly encourage framework authors to never reuse task IDs.) Neil [1] https://reviews.apache.org/r/54179/
