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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