Summary of problems encountered in installing hive in Hadoop environment

Question 1: Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: The following error is reported when starting hive:

Exception in thread "main" java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
    at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:591)
    at org.apache.hadoop.hive.ql.session.SessionState.beginStart(SessionState.java:531)
    at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:705)
    at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:641)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

Reason: Because the Metastore Server service process of Hive is not started normally.
Solution: Start the Metastore Server service process of Hive and execute the following command:

hive --service metastore

Question 2 Start hive

Caused by: org.datanucleus.store.rdbms.connectionpool.DatastoreDriverNotFoundException: The specified datastore driver ("com.mysql.jdbc.Drive") was not found in the CLASSPATH. Please check your CLASSPATH specification, and the name of the driver.
        at org.datanucleus.store.rdbms.connectionpool.AbstractConnectionPoolFactory.loadDriver(AbstractConnectionPoolFactory.java:58)
        at org.datanucleus.store.rdbms.connectionpool.BoneCPConnectionPoolFactory.createConnectionPool(BoneCPConnectionPoolFactory.java:54)
        at org.datanucleus.store.rdbms.ConnectionFactoryImpl.generateDataSources(ConnectionFactoryImpl.java:238)

Reason: The package com.mysql.jdbc.Driver was not found
Solution : Provide you with a download address:
http://dev.mysql.com/downloads/connector/j/
After downloading and decompressing,
put mysql-connector-java -5.0-nightly-20071116-bin.jar This package can be placed directly in the lib directory of hive

Question 3 MySQL connection refused error appears when starting hive

Caused by: javax.jdo.JDOFatalDataStoreException: Unable to open a test connection to the given database. JDBC url = jdbc:mysql://master:3306/hive?createDatabaseIfNotExist=true, username = root. Terminating connection pool (set lazyInit to true if you expect to start your database after your app). Original Exception: ------
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Caused by: java.net.ConnectException: 拒绝连接
    at java.net.PlainSocketImpl.socketConnect(Native Method)

Reason: 1: Permission problem 2: Is there any error in the hive-site.xml configuration database
Solution :
1: Enter the following commands in sequence on the command line

mysql -uroot -proot
grant all privileges on *.* to root@'locathost' identified by 'root';
flush privileges;
exit;

2: My hive-site.xml configuration is as follows

<property>
    <name>javax.jdo.option.ConnectionURL</name>
    <value>jdbc:mysql://localhost:3306/hive?createDatabaseIfNotExist=true</value>
</property>
<property>
    <name>javax.jdo.option.ConnectionDriverName</name>
    <value>com.mysql.jdbc.Driver</value>
</property>
<property>
    <name>javax.jdo.option.ConnectionUserName</name>
    <value>root</value>
</property>
<property>
    <name>javax.jdo.option.ConnectionPassword</name>
    <value>root</value>
</property>

Question 4 The error when starting hive is as follows:

Logging initialized using configuration in file:/home/yulore/mile/hive/apache-hive-2.1.1-bin/conf/hive-log4j2.properties Async: true
Exception in thread "main" java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
    at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:591)
    at org.apache.hadoop.hive.ql.session.SessionState.beginStart(SessionState.java:531)
    at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:705)
    at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:641)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

Reason: metadata is not
instantiated Solution: Enter at the command line

schematool -dbType mysql -initSchema

Question 5: When starting hive, it reports an error: Name node is in safe mode

Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.SafeModeException): Cannot create directory /tmp/hive/yulore/cbd1aaf8-e100-4872-9cf5-6d8b98aaee13. Name node is in safe mode.
The reported blocks 0 needs additional 4 blocks to reach the threshold 0.9990 of total blocks 4.
The number of live datanodes 1 has reached the minimum number 0. Safe mode will be turned off automatically once the thresholds have been reached.
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkNameNodeSafeMode(FSNamesystem.java:1364)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInt(FSNamesystem.java:4216)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:4191)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:813)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.mkdirs(ClientNamenodeProt

Solution: bin/hadoop dfsadmin -safemode leave found on the Internet

For other problems I haven't encountered yet, please refer to: https://blog.csdn.net/freedomboy319/article/details/44828337