[jira] [Created] (AMBARI-20682) Wait For DataNodes To Shutdown During a Rolling Upgrade

["Dmitry Lysnichenko (JIRA)" <ji...@apache.org>]

Dmitry Lysnichenko created AMBARI-20682:
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             Summary: Wait For DataNodes To Shutdown During a Rolling Upgrade
                 Key: AMBARI-20682
                 URL: https://issues.apache.org/jira/browse/AMBARI-20682
             Project: Ambari
          Issue Type: Bug
            Reporter: Dmitry Lysnichenko
            Assignee: Dmitry Lysnichenko
            Priority: Critical
         Attachments: AMBARI-20682.patch


During a rolling upgrade (especially on a large, heavily used cluster), the DataNodes do not shutdown immediately. However, they do de-register from the NameNode which tricks Ambari into thinking that they are down.

Since the rolling upgrade uses a {{RESTART}} command, we attempt to start the DataNode back up before the daemon has shutdown:

{code}
2017-03-14 05:00:25,602 - call['/usr/hdp/current/hadoop-hdfs-datanode/bin/hdfs dfsadmin -fs hdfs://c1ha -shutdownDatanode 0.0.0.0:8010 upgrade'] {'user': 'hdfs'}
2017-03-14 05:00:28,438 - call returned (0, 'Submitted a shutdown request to datanode 0.0.0.0:8010')
2017-03-14 05:00:28,438 - Execute['/usr/hdp/current/hadoop-hdfs-datanode/bin/hdfs dfsadmin -fs hdfs://c1ha -D ipc.client.connect.max.retries=5 -D ipc.client.connect.retry.interval=1000 -getDatanodeInfo 0.0.0.0:8010'] {'tries': 1, 'user': 'hdfs'}
2017-03-14 05:00:35,976 - DataNode has successfully shutdown for upgrade.
{code}

Even though ~ 6 seconds have passed, the daemon is still running as it drains. Therefore, we attempt to start it which causes a NOOP.

Instead, we should also monitor for the PID.





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