[jira] [Created] (ACCUMULO-4424) Do not wait to start Thrift servers until lock is acquired

["Josh Elser (JIRA)" <ji...@apache.org>]

Josh Elser created ACCUMULO-4424:
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             Summary: Do not wait to start Thrift servers until lock is acquired
                 Key: ACCUMULO-4424
                 URL: https://issues.apache.org/jira/browse/ACCUMULO-4424
             Project: Accumulo
          Issue Type: Improvement
          Components: rpc
            Reporter: Josh Elser
            Assignee: Josh Elser


Had an Accumulo + Ambari user report a funny issue: https://community.hortonworks.com/questions/53203/ambari-is-showing-alerts-on-the-accumulo-service-e.html

When starting multiple masters, monitors, GC's: they observed that, despite Accumulo being healthy, Ambari kept reporting that 2/3rd of each service were down. This is because Ambari is expecting that the Thrift service is up as a service check.

Presently, for services where only one active instance is allowed, we do not put up the thrift server until we acquire the leader ZK lock. I propose that we still start these servers but introduce a barrier to prevent any API calls from succeeding until the leader lock is obtained. This has a couple of benefits:

* Better "health" check -- processes might be zombie'd, pidfile check would be insufficient
* Less confusion around process which is running but not binding the port (have personally dealt with a case where a user was confused and thought the services where incorrectly stuck on startup)

I believe this would also be pretty simple to do since the leader election is already implemented in one place (just the znode differs).



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