Neil Conway commented on MESOS-6660:

[~anandmazumdar] [~vinodkone]

> 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
>              Labels: mesosphere
> 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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