SLIDER-167: Automatically copy slider-agent.tar.gz when creating an application

[Sumit Mohanty <sm...@hortonworks.com>]

While I was listing the upgrade scenarios, it seems that the solution for
SLIDER-167 will have to be discussed in light of upgrade.

If each application instance has their own copy of AppMaster jars (today
they do) and the Agent tarball then user can selectively upgrade Slider on
a per app-instance basis. Because it cannot be prevented that users have a
per app-instance copy of Slider, we might as well assume it to be the
standard.

This brings in few scenarios:

   - Version mismatch between Slider Client, AppMaster, and Agent
   - We should implement a mechanism to log version mismatches or even WARN
      if there ever is incompatible changes
   - Upgrade of Slider is now a per app-instance activity
   - We should plan on some form of tooling to make it easier to upgrade
      multiple apps at the same time
   - If Slider upgrade requires app-instance to be stopped then the above
   procedure should be valid
   - If Slider supports rolling upgrade then also the above approach may
   hold
   - Rolling upgrade requires Slider-Client/AppMaster/Agent libraries to be
      upgraded and then do a AppMaster restart followed by
orchestrated container
      restarts (*assuming YARN will add capability to this end if necessary*
      )
      - Assumption being while AppMaster and Containers are active they
      won't get affected by updating Slider libraries in HDFS
      - We may need a command to prepare AppMaster for upgrade where it may
      store some additional information such as old/new version, not entertain
      any form of update including allocating new containers if any fail
      - Issue an AppMaster restart such that the restart picks the new
      version of AppMaster
      - Issue a rolling restart of all containers

If a user wants single copy of Slider? Opened a different JIRA to address
that topic.

-Sumit

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