https://community.cloudera.com/t5/Support-Questions/Oozie-database-access-problem/m-p/194082#M156142 <P>After install HDP2.6.3 and Ambari2.6.2.2, In oozie-error.log, I found some strange information about database connection problem.</P><P>-----------------</P><P>2018-07-19 09:29:17,244 ERROR SchemaCheckXCommand:517 - SERVER[hadoopS4] USER[-] GROUP[-] TOKEN[-] APP[-] JOB[-] ACTION[-] An Exception occured while talking to the database: Access denied for user 'root'@'hadoopS4' (using password: YES) java.sql.SQLException: Access denied for user 'root'@'hadoopS4' (using password: YES) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871) at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1686) at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1207) at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2254) at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2285) at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084) at com.mysql.jdbc.ConnectionImpl.&lt;init&gt;(ConnectionImpl.java:795) at com.mysql.jdbc.JDBC4Connection.&lt;init&gt;(JDBC4Connection.java:44) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at com.mysql.jdbc.Util.handleNewInstance(Util.java:404) at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327) at java.sql.DriverManager.getConnection(DriverManager.java:664) at java.sql.DriverManager.getConnection(DriverManager.java:247) at org.apache.oozie.command.SchemaCheckXCommand.execute(SchemaCheckXCommand.java:88) at org.apache.oozie.command.SchemaCheckXCommand.execute(SchemaCheckXCommand.java:63) at org.apache.oozie.command.XCommand.call(XCommand.java:287) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at org.apache.oozie.service.CallableQueueService$CallableWrapper.run(CallableQueueService.java:178) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)</P><P>-----------------</P><P>I am sure below things are fine:</P><P>1. jdbc-mysql.jar has been added.</P><P>2. use command could connect oozie database from oozie server. "mysql -uroot -pxxxx -hhadoops4".</P><P>3. Install oozie from ambari. the db connection is fine.</P><P>4. All of oozie tables were created automatically during oozie installation.</P> Thu, 19 Jul 2018 08:47:12 GMT 393219974 2018-07-19T08:47:12Z