[jira] [Updated] (AMBARI-14842) ambari agent upstart support

["Andrew Onischuk (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMBARI-14842?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Onischuk updated AMBARI-14842:
-------------------------------------
    Attachment: AMBARI-14842.patch

> ambari agent upstart support
> ----------------------------
>
>                 Key: AMBARI-14842
>                 URL: https://issues.apache.org/jira/browse/AMBARI-14842
>             Project: Ambari
>          Issue Type: Bug
>            Reporter: Andrew Onischuk
>            Assignee: Andrew Onischuk
>             Fix For: 2.4.0
>
>         Attachments: AMBARI-14842.patch
>
>
> Context:  
> It is critical that we have a service that can auto-restart during crashes and
> reboots. This is done via upstart on Ubuntu.  
> The issue is that Ambari-Agent scripts in the current state is not upstart-
> able due to some implementation issues.  
> So to make this upstart-able, we had to directly take a dependency into a
> helper script for Ambari-Agent (as per user1 recommendation). However, this
> dependency turned out to be fragile, since it broke in HDP 2.4. So this JIRA
> is about making ambari agent upstartable directly when we install Ambari, so
> users doesn’t have to resort to a fragile dependency. We made it work  
> Details:  
> The way to start ambari-agent and ambari-server are different for user1 and
> user2.  
> In the case for ambari-agent:  
> user1 calls "/etc/init.d/ambari-agent" (which invokes /usr/sbin/ambari-agent)
> to start ambari agent.  
> user2 uses "/etc/init/ambari-agent" (which directly calls /usr/lib/python2.6
> /site-packages/ambari_agent/main.py) to start ambari-agent.  
> user2 has to call ambari-agent/main.py directly is because we need upstart to
> re-start services when it crashes unexpectedly and upstart does not work if we
> configure it to call /usr/sbin/ambari-agent.  
> The reason is that upstart needs to track the process for the service (i.e.
> ambari-agent) that it needs to restart; however, /usr/sbin/ambari-agent
> executes lots of commands that would result in new processes being spawned and
> will confuse upstart the "main" process it should be tracking.  
> We need user1 to give us a upstart-compatible script otherwise HDP changes can
> break us unexpectedly.  
> We also have a upstart script for ambari-server for the same reason.  
> Attaching both scripts for user1 to take a look.



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