[MESOS-5740] Consider adding `relink` functionality to libprocess

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.28.3, 1.0.0
• Component/s: libprocess
• Labels: libprocess mesosphere
• Sprint: Mesosphere Sprint 38
• Story Points: 3
• Assignee: Joseph Wu
• Reporter: Joseph Wu
• Shepherd: Benjamin Mahler
• Created: 29/Jun/16 02:24
• Updated: 22/Sep/16 23:35
• Resolved: 30/Jun/16 01:34

Description

Currently we don't have the relink functionality in libprocess. i.e. A way to create a new persistent connection between actors, even if a connection already exists.

This can benefit us in a couple of ways:

• The application may have more information on the state of a connection than libprocess does, as libprocess only checks if the connection is alive or not. For example, a linkee may accept a connection, then fork, pass the connection to a child, and subsequently exit. As the connection is still active, libprocess may not detect the exit.
• Sometimes, the ExitedEvent might be delayed or might be dropped due to the remote instance being unavailable (e.g., partition, network intermediaries not sending RST's etc).

Issue Links

• is related to: MESOS-5364 Consider adding `unlink` functionality to libprocess
• is related to: MESOS-5576 Masters may drop the first message they send between masters after a network partition
• is related to: MESOS-4092 Try to re-establish connection on ping timeouts with agent before removing it
• relates to: MESOS-6233 Master CHECK fails during recovery while relinking to other masters
• relates to: MESOS-6234 Potential socket leak during Zookeeper network changes