[jira] [Created] (MESOS-6660) Status updates and disconnected frameworks

["Neil Conway (JIRA)" <ji...@apache.org>]

Neil Conway created MESOS-6660:
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             Summary: Status updates and disconnected frameworks
                 Key: MESOS-6660
                 URL: https://issues.apache.org/jira/browse/MESOS-6660
             Project: Mesos
          Issue Type: Improvement
          Components: master
            Reporter: Neil Conway


When the master receives a status update, it invokes {{Master::forward}} to send the status update to the framework. {{Master::forward}} also updates the task's {{status_update_state}} and {{status_update_uuid}} fields. However, {{Master::forward}} is not invoked for disconnected frameworks.

This scheme has the following drawbacks:

# Logically, {{Master::forward}} probably shouldn't be updating the state of a task; {{forward}} should just forward messages.
# The reasoning for not updating {{status_update_state}} and {{status_update_uuid}} for disconnected frameworks is to try to avoid inconsistencies upon framework reconciliation -- we don't want reconciliation to show update X, but then the framework to receive a non-reconciliation update Y, such that Y comes before X in the agent's order. I'm not sure that this is actually a problem (since we wait for framework acks before forwarding subsequent status updates), but in any case, depending on framework connectivity _cannot_ be a correct fix: whether the master thinks the framework is connected at a given time is unreliable and racy (i.e., the master might think the framework is disconnected but it still might receive messages; similarly, "connected" frameworks might not receive messages).



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