[MESOS-7578] Write a proposal to make the I/O Switchboards optional

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.5.0
• Component/s: containerization
• Labels: check containerizer health-check mesosphere
• Epic Link: HealthChecks
• Sprint: Mesosphere Sprint 57
• Story Points: 5
• Docs Text: https://docs.google.com/document/d/1YCMtH8i2-ovTVtKDsCTrXdygS7ieaSrJLVnFbR66qfA/
• Assignee: Unassigned
• Reporter: Gastón Kleiman
• Shepherd: Vinod Kone
• Created: 26/May/17 21:21
• Updated: 07/Jan/19 22:56
• Resolved: 14/Oct/17 04:05

Description

Right now DEBUG containers can only be started using the LaunchNestedContainerSession API call. They will enter its parent’s namespaces, inherit environment variables, stream its I/O, and Mesos will tie their life-cycle to the lifetime of the HTTP connection.

Streaming the I/O of a container requires an I/O Switchboard and adds some overhead and complexity:

• Mesos will launch an extra process, called an I/O Switchboard for each nested container. These process aren’t free, they take some time to create/destroy and consume resources.
• I/O Switchboards are managed by a complex isolator.
• /O Swichboards introduce new race conditions, and have been a source of deadlocks in the past.

Some use cases require some of the features provided by DEBUG containers, but don’t need the functionality provided by the I/O switchboard. For instance, the Default Executor uses DEBUG containers to perform (health)checks, but it doesn’t need to stream anything to/from the container.

Issue Links

• is related to: MESOS-7500 Command checks via agent lead to flaky tests.
• relates to: MESOS-7121 Make IO Switchboard optional for debug containers