[MESOS-3863] Investigate the requirements of programmatically re-initializing libprocess

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Done
• Component/s: libprocess, test
• Labels: mesosphere
• Epic Link: libprocess-finalize
• Sprint: Mesosphere Sprint 22
• Story Points: 2
• Assignee: Joseph Wu
• Reporter: Joseph Wu
• Shepherd: Joris Van Remoortere
• Created: 09/Nov/15 22:13
• Updated: 26/Nov/18 12:34
• Resolved: 26/Nov/18 12:34

Description

This issue is for investigating what needs to be added/changed in process::finalize such that process::initialize will start on a clean slate. Additional issues will be created once done. Also see the parent issue.

process::finalize should cover the following components:

• _s_ (the server socket)
  • delete should be sufficient. This closes the socket and thereby prevents any further interaction from it.
• process_manager
  • Related prior work: MESOS-3158
  • Cleans up the garbage collector, help, logging, profiler, statistics, route processes (including this one, which currently leaks a pointer).
  • Cleans up any other spawn 'd process.
  • Manages the EventLoop.
• Clock
  • The goal here is to clear any timers so that nothing can deference process_manager while we're finalizing/finalized. It's probably not important to execute any remaining timers, since we're "shutting down" libprocess. This means:
    • The clock should be paused and settled before the clean up of process_manager.
    • Processes, which might interact with the Clock, should be cleaned up next.
    • A new Clock::finalize method would then clear timers, process-specific clocks, and tick s; and then resume the clock.
• _address_ (the advertised IP and port)
  • Needs to be cleared after process_manager has been cleaned up. Processes use this to communicate events. If cleared prematurely, TerminateEvents will not be sent correctly, leading to infinite waits.
• socket_manager
  • The idea here is to close all sockets and deallocate any existing HttpProxy or Encoder objects.
  • All sockets are created via _s_, so cleaning up the server socket prior will prevent any new activity.
• mime
  • This is effectively a static map.
  • It should be possible to statically initialize it.
• Synchronization atomics initialized & initializing.
  • Once cleanup is done, these should be reset.

Summary:

• Implement Clock::finalize. MESOS-3882
• Implement ~SocketManager. MESOS-3910
• Make sure the MetricsProcess and ReaperProcess are reinitialized. MESOS-3934
• (Optional) Clean up mime.
• Wrap everything up in process::finalize.