Connect Java to HBase Remotedly

Question

I'm trying to connect Java to HBase in remote server.

Here is the case :

The java class is in my local computer (192.168.111.165)

The Hadoop File System and HBase is in another server (192.168.11.7)

Here is my Hadoop's core-site.xml (in 192.168.11.7) :

<configuration>
  <property>
        <name>fs.default.name</name>
        <value>hdfs://192.168.11.7:9000</value>
  </property>
</configuration>

Here is my Hadoop's hdfs-site.xml (in 192.168.11.7) :

<configuration>
  <property>
        <name>dfs.replication</name>
        <value>1</value>
  </property>
  <property>
    <name>dfs.name.dir</name>
    <value>file:///home/hadoop/hadoopinfra/hdfs/namenode</value>
  </property>

  <property>
    <name>dfs.data.dir</name>
    <value>file:///home/hadoop/hadoopinfra/hdfs/datanode</value>
  </property>   
</configuration>

Here is my HBase's hbase-site.xml (in 192.168.11.7) :

<configuration>
  <property>
    <name>hbase.rootdir</name>
    <value>hdfs://192.168.11.7:9000/hbase</value>
  </property>

  <property>
    <name>hbase.zookeeper.property.dataDir</name>
    <value>/home/hadoop/zookeeper</value>
  </property>

  <property>
    <name>hbase.cluster.distributed</name>
    <value>true</value>
  </property>
</configuration>

I have turned on HDFS and HBase successfully (proven with I can run "list" command in HBase shell). Note that I run the "list" command in HBase Shell using ssh to 192.168.11.7 from my local computer. From my local computer (192.168.111.165), I can access hadoop file system and hbase using browser (hadoop by hitting URL : http://192.168.11.7:50070/, hadoop cluster by hitting URL : http://192.168.11.7:8088/, HBase by hitting URL : http://192.168.11.7:16010/)

Now, I develop a Java Code in my local computer (192.168.111.165), which has the hbase-site.xml :

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
  <configuration>
    <property>
      <name>hbase.rootdir</name>
      <value>hdfs://192.168.11.7:9000/hbase</value>
    </property>
</configuration>

and my Main code as follows :

private static Configuration conf = null;

public static void main(String[] args) throws Exception {
    try {
        conf = HBaseConfiguration.create();
        String tablename = "scores";
        String[] familys = { "grade", "course" };
        creatTable(tablename, familys);
    } catch (Exception e) {
        e.printStackTrace();

        throw e;
    }
}

public void creatTable(String tableName, String[] familys)
        throws Exception {
    HBaseAdmin admin = new HBaseAdmin(conf);
    if (admin.tableExists(tableName)) {
        System.out.println("table already exists!");
    } else {
        HTableDescriptor tableDesc = new HTableDescriptor(tableName);
        for (int i = 0; i < familys.length; i++) {
            tableDesc.addFamily(new HColumnDescriptor(familys[i]));
        }
        admin.createTable(tableDesc);
        System.out.println("create table " + tableName + " ok.");
    }
}

When I run the code, I got Exception, which has the stacktrace :

org.apache.hadoop.hbase.client.RetriesExhaustedException: Can't get the locations
at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:319)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:156)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:60)
at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:210)
at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:326)
at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:301)
at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:166)
at org.apache.hadoop.hbase.client.ClientScanner.<init>(ClientScanner.java:161)
at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:797)
at org.apache.hadoop.hbase.MetaTableAccessor.fullScan(MetaTableAccessor.java:602)
at org.apache.hadoop.hbase.MetaTableAccessor.tableExists(MetaTableAccessor.java:366)
at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:406)
at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:416)
at com.volt.kismistest.handler.TestHBaseHandler.creatTable(TestHBaseHandler.java:82)
at com.volt.kismistest.handler.TestHBaseHandler.doAction(TestHBaseHandler.java:47)
at com.volt.kismistest.handler.TestHBaseHandler.doAction(TestHBaseHandler.java:1)

Note in the exception is :

TestHBaseHandler is the name of my java class

TestHBaseHandler.java:82 is : if (admin.tableExists(tableName)) { on the creatTable method

TestHBaseHandler.java:47 is : creatTable(tablename, familys); on the main method

Can anyone help me fixing this problem?

Thank you very much

Mike Thomsen Mike Thomsen · Accepted Answer · 2016-09-28T10:49:30

You said you could run list, but can you run create and scan on a particular table? It's possible that you forgot to start the region server. I would run something like this:

create testtable, {NAME => 'testcf'} to see if that creates it in the shell as well. If that somehow works, run scan 'testtable' to verify that you can scan it.

Could also be a firewall issue. The region server might be up but its ports firewalled off.

Another thing, you can also call HBaseAdmin#available to check whether or not HBase is up and running from your client.

Connect Java to HBase Remotedly

2 Answers