[jira] [Created] (ACCUMULO-3382) client only connects to first zookeeper instance

["Brian Loss (JIRA)" <ji...@apache.org>]

Brian Loss created ACCUMULO-3382:
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             Summary: client only connects to first zookeeper instance
                 Key: ACCUMULO-3382
                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3382
             Project: Accumulo
          Issue Type: Bug
          Components: client, mapreduce
    Affects Versions: 1.6.1
            Reporter: Brian Loss
            Assignee: Eric Newton


When using a ClientConfiguration (or a ZookeeperInstance) to connect to accumulo, the connection will only ever use the first zookeeper in the list provided. When connections are made from a mapreduce job, this can lead to the first zookeeper server becoming overloaded.

The underlying problem seems to be in ClientConfiguration:
{code:java}
ClientConfiguration cc = ClientConfiguration.loadDefault().withZkHosts("host1,host2,host3");
// Will only return "host1" and not "host1,host2,host3"
System.out.println(cc.get(ClientConfiguration.ClientProperty.INSTANCE_ZK_HOST));
{code}
This is happening because ClientConfiguration extends CompositeConfiguration, a class in commons-configuration. On of the default features is that if you set a property that is a comma-delimited list of values, it creates a list property. If you retrieve the property value using getString, then only the first value in the list will be returned.

It seems there are a couple solutions to this problem:
1. Disable the automatic list parsing. This is trivial by simply calling setDelimiterParsingDisabled(true) in the ClientConfiguration constructor.
2. Change the way all properties that are intended to be a comma-separated list are retrieved such that the appropriate list-based retrieval method is used.




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