[SPARK-1882] Support dynamic memory sharing in Mesos

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 1.0.0
• Component/s: Mesos
• Assignee: Unassigned
• Reporter: Andrew Ash
• Created: 19/May/14 18:39
• Updated: 09/Jun/16 11:13
• Resolved: 13/Jan/16 11:56

Description

Fine grained mode Mesos currently supports sharing CPUs very well, but requires that memory be pre-partitioned according to the executor memory parameter. Mesos supports dynamic memory allocation in addition to dynamic CPU allocation, so we should utilize this feature in Spark.

See below where when the Mesos backend accepts a resource offer it only checks that there's enough memory to cover sc.executorMemory, and doesn't ever take a fraction of the memory available. The memory offer is accepted all or nothing from a pre-defined parameter.

Coarse mode:
https://github.com/apache/spark/blob/3ce526b168050c572a1feee8e0121e1426f7d9ee/core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackend.scala#L208

Fine mode:
https://github.com/apache/spark/blob/a5150d199ca97ab2992bc2bb221a3ebf3d3450ba/core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosSchedulerBackend.scala#L114

Issue Links

• relates to: SPARK-4922 Support dynamic allocation for coarse-grained Mesos