How to get regionservers' startcode in a HBase cluster?

Question

my HBase cluster's load unbalanced, so i want to move some regions of table from one regionsserver to other, but it seems that a startcode of a regionserver is needed to do this,how can i get this startcode?

i noticed that someone's master-status page is like this:

but mine is like this:

where can i get the startcode?

actually, i want to move a region from regionserver k3 to regionserver k2, and the regions on k3 are:

how can i do this? in detail :)

Answer 1

okay, finally i worked it out.

/*
 * Copyright: Copyright (c) 2012 Kaliumn
 * 
 * @Description: get regionservers' startcode in a hbase cluster
 * 
 */

package test.hbase;

import java.util.Collection;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HServerInfo;
import org.apache.hadoop.hbase.MasterNotRunningException;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.ZooKeeperConnectionException;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.ipc.HMasterInterface;
import org.gfg.kalium.server.hbaseutil.HConfUtils;

/**
 * class <code> GetStartcode </code> is used to get regionservers' startcode
 * 
 * @author <a href="mailto:[email protected]">Meilong Huang</a>
 * @version v1.0.0
 * @date 2012-6-26 05:24:10
 * 
 */

public class GetStartcode {

    /**
     * get regionservers' startcode
     * 
     * @param args
     * @throws ZooKeeperConnectionException
     * @throws MasterNotRunningException
     */
    public static void main(String[] args) throws MasterNotRunningException,
            ZooKeeperConnectionException {
        Configuration conf = HConfUtils
                .setHbaseConf("k2.ccntgrid.org,k3.ccntgrid.org,k4.ccntgrid.org");
        HBaseAdmin admin = new HBaseAdmin(conf);
        HMasterInterface master = admin.getMaster();
        Collection<ServerName> rs = master.getClusterStatus().getServerInfo();
        for (ServerName r : rs) {
            System.out.println(r.getHostname());
            System.out.println(r.getServerName());
            System.out.println(r.getStartcode());
            System.out.println("+++++++++++++++++");
        }
    }
}

actually, startcode is the last part of the 'servername'.

these commands will finish moving regions from one regionserver to other:

> ka@k1 bin % pwd
> /opt/kalium/hbase/bin


> ka@k1 bin % echo "move '3504a80cd4047f78834bcf58bf169e62', 'k4.ccntgrid.org,60020,1340682441023'" | ./hbase shell 
> HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version 0.92.1, r1298924, Fri Mar  9 16:58:34 UTC 2012

> move '3504a80cd4047f78834bcf58bf169e62', 'k4.ccntgrid.org,60020,1340682441023'
0 row(s) in 0.5380 seconds

u need the the region code to finish this. the region code is the last part of the region name(behind a dot(.)).

Answer 2

You can use the command status in the hbase shell:

hbase(main):001:0> status 'simple'

It will print the list of region servers with their server names, ports and startcodes.