Hadoop | ServerNotRunningYetException and PleaseHoldException

Problem 1: ERROR: org.apache.hadoop.hbase.ipc.ServerNotRunningYetException: Server is not running yet

While running the hbase shell sometimes we receive Server is Not Running Yet error while our hbase master server is running properly.

Solution: This problem occurs when we fetch the data from the hdfs for hbase in our local system. In this case our namenode or datanode is in safe mode. In safe mode we cannot insert data in hdfs.

So we need to leave the safe mode to insert data in hdfs or hbase table in hdfs. We can use following command to leave the safe mode of the namenode or datanode:

hadoop@usrHadoop:~$ hdfs dfsadmin -safemode leave

On successful execution this message is shown:

Safe mode is OFF

And after this above error does not occur and the hive shell runs properly.

Problem 2 ERROR: org.apache.hadoop.hbase.PleaseHoldException: Master is initializing at org.apache.hadoop.hbase.master.HMaster.checkInitialized(HMaster.java:2289)

While running the hbase shell sometimes we receive this error that Master is Initializing while our hbase master server is Running properly.

Solution: This error occurs when zookeeper server is not running properly. To overcome this problem we have to follow these steps:

Stop the zookeeper server using command.
bin/zkServer.sh stop
Delete all the data in the data directory created to store the runtime data
Restart the zookeeper.

Now hbase works properly.