[jira] [Commented] (MESOS-6818) Ensure empty contents in persistent volume if disk not in use.

["Anindya Sinha (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MESOS-6818?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15763184#comment-15763184 ] 

Anindya Sinha commented on MESOS-6818:
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To handle this case, we can determine if disks are empty or not at agent startup and looking at the contents of the checkpoint info at that time. If there is a disk that contains old data, there are 2 approaches that can be done:

a) Do not allow the agent to register with the master. It would therefore require an operator to clean/format the disk (or change the static resources pertaining to these unclean disks.
b) Allow the agent to register with disks that have clean contents only. Say, the --resources flag indicates 4 disks of which 1 of the disk is unclean (i.e. old data exists), the agent advertises only 3 disks as available resources.


> Ensure empty contents in persistent volume if disk not in use.
> --------------------------------------------------------------
>
>                 Key: MESOS-6818
>                 URL: https://issues.apache.org/jira/browse/MESOS-6818
>             Project: Mesos
>          Issue Type: Improvement
>          Components: general
>            Reporter: Anindya Sinha
>            Priority: Minor
>              Labels: persistent-volumes
>
> Currently, when a persistent volume is DESTROYed, we ensure that `rmdir` of that directory is successful before returning that disk as an offereable resource. So, when a CREATE is received for the same path, we thereby ensure that the contents of that path is empty (MOUNT disks will have the root present though). This ensures that frameworks of the same role do not leak content to other frameworks. Reference: MESOS-5448.
> However, an agent might join a cluster who do not have the path corresponding to the disks clean. One of the scenarios might be if the agents join a new cluster after being repurposed from another cluster without their disks being formatted. In such a case, the CREATE of a persistent volume on an existing path might contain data left over from a previous run in the old cluster which might lead to inconsistencies esp if the tasks running in the container *always* expect to receive a clean persistent volume.



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