org.apache.hadoop.hbase.regionserver.HRegionServer ABORTING region server Unhandled exception org.apache.hadoop.hbase.ClockOutOfSyncException

org.apache.hadoop.hbase.regionserver.HRegionServer: ABORTING region server : Unhandled exception: org.apache.hadoop.hbase.ClockOutOfSyncException:

This error occurs due to time synchronization between the nodes of the cluster, if the time difference between the node is more that 30000ms between the master and slave time then this error comes:

What is the solution ????

Do the following :

Install ntpd at the master using following method :

For Ubuntu flavor:

1. sudo apt-get install ntpd
2. vi /etc/ntp.conf
3. sudo service ntp restart
4. ps -ef | grep ntp
5. netstat -na | grep 123 

For Red Hat flavor:

1. iptables -I INPUT -p udp --dport 123 -j ACCEPT -->"allows NTP traffic from ANY source"
2. yum install ntp
3. server 0.us.pool.ntp.org
4. server wwv.nist.gov
5. restrict 0.us.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
6. restrict wwv.nist.gov mask 255.255.255.255 nomodify notrap noquery  
7. restrict 10.0.0.0 mask 255.255.255.0 nomodify notrap
8. restrict 127.0.0.1
9. ntpq -p 0.us.pool.ntp.org   
10. /etc/init.d/ntpd start
11. chkconfig ntpd on

 So the NTPD is up and running then:

    sudo ntpdate -b<IP Address of Slave Node>   -> this will synchronise the master time with slave.