[jira] [Updated] (MESOS-8185) Tasks can be known to the agent but unknown to the master.

["Benjamin Mahler (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MESOS-8185?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Benjamin Mahler updated MESOS-8185:
-----------------------------------
    Summary: Tasks can be known to the agent but unknown to the master.  (was: Master should kill tasks that are unknown to it after registered agent re-registers)

> Tasks can be known to the agent but unknown to the master.
> ----------------------------------------------------------
>
>                 Key: MESOS-8185
>                 URL: https://issues.apache.org/jira/browse/MESOS-8185
>             Project: Mesos
>          Issue Type: Bug
>    Affects Versions: 1.2.0
>            Reporter: Ilya Pronin
>
> Currently, when a master re-registers an agent that was marked unreachable, it shutdowns all not partition-aware frameworks on that agent. When a master re-registers an agent that is already registered, it doesn't check that all tasks from the slave's re-registration message are known to it.
> It is possible that due to a transient loss of connectivity an agent may miss {{SlaveReregisteredMessage}} along with {{ShutdownFrameworkMessage}} and thus will not kill not partition-aware tasks. But the master will mark the agent as registered and will not re-add tasks that it thought will be killed. The agent may re-register again, this time successfully, before becoming marked unreachable while never having terminated tasks of not partition-aware frameworks. The master will simply forget those tasks ever existed, because it has "removed" them during the previous re-registration.
> Example scenario:
> # Connection from the master to the agent stops working
> # Agent doesn't see pings from the master and attempts to re-register
> # Master sends {{SlaveRegisteredMessage}} and {{ShutdownSlaveMessage}}, which don't get to the agent because of the connection failure. Agent is marked registered.
> # Network issue resolves, connection breaks. Agent retries re-registration.
> # Master thinks that the agent was registered since step (3) and just re-sends {{SlaveRegisteredMessage}}. Tasks remain running on the agent.
> One of the possible solutions would be to compare the list of tasks the the already registered agent reports in {{ReregisterSlaveMessage}} and the list of tasks the master has. In this case anything that the master doesn't know about should not exist on the agent.



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