cloudera-scm-server启动时出现Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection问题解决方法（图文详解）

　　问题现象

　　　　查看

[root@cmbigdata1 cloudera-scm-server]# pwd
/var/log/cloudera-scm-server
[root@cmbigdata1 cloudera-scm-server]# cat cloudera-scm-server.log 

　　　　是如下的问题：

Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:)
    at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:)
    at com.cloudera.enterprise.AbstractWrappedEntityManager.beginForRollbackAndReadonly(AbstractWrappedEntityManager.java:)
    at com.cloudera.enterprise.dbutil.DbUtil.isInnoDbEnabled(DbUtil.java:)
    at com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean.checkMysqlTableEngineType(EntityManagerFactoryBean.java:)
    at com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean.getObject(EntityManagerFactoryBean.java:)
    at com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean.getObject(EntityManagerFactoryBean.java:)
    at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:)
    ...  more
Caused by: org.hibernate.exception.GenericJDBCException: Could not open connection
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:)
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:)
    ...  more
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:)
    at org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:)
    ...  more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
    at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:)
    at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:)
    at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:)
    ...  more
-- ::, INFO main:com.cloudera.server.cmf.Main: Starting SCM Server. JVM Args: [-Dlog4j.configuration=file:/etc/cloudera-scm-server/log4j.properties, -Dfile.encoding=UTF-, -Dcmf.root.logger=INFO,LOGFILE, -Dcmf.log.dir=/var/log/cloudera-scm-server, -Dcmf.log.file=cloudera-scm-server.log, -Dcmf.jetty.threshhold=WARN, -Dcmf.schema.dir=/usr/share/cmf/schema, -Djava.awt.headless=true, -Djava.net.preferI

[root@cmbigdata1 lib]# netstat -nltp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name
tcp               0.0.0.0:                 0.0.0.0:*                   LISTEN      /rpcbind
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:               0.0.0.0:*                   LISTEN      /rpc.statd
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:                  0.0.0.0:*                   LISTEN      /sshd
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /python2.
tcp               127.0.0.1:               0.0.0.0:*                   LISTEN      /cupsd
tcp               127.0.0.1:             0.0.0.0:*                   LISTEN      /python
tcp               127.0.0.1:                0.0.0.0:*                   LISTEN      /master
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /sshd
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /sshd
tcp               192.168.80.31:          0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /mysqld
tcp               :::                      :::*                        LISTEN      /rpcbind
tcp               :::                     :::*                        LISTEN      /python2.
tcp               :::                       :::*                        LISTEN      /sshd
tcp               :::                     :::*                        LISTEN      /python2.
tcp               :::                     :::*                        LISTEN      /cupsd
tcp               :::                      :::*                        LISTEN      /master
tcp               :::                    :::*                        LISTEN      /rpc.statd
tcp               :::                    :::*                        LISTEN      /sshd
tcp               :::                    :::*                        LISTEN      /sshd       

解决办法

[root@cmbigdata1 lib]# service mysqld start
Starting mysqld:                                           [  OK  ]
[root@cmbigdata1 lib]# 

[root@cmbigdata1 lib]# netstat -nltp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /java
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /java
tcp               0.0.0.0:                 0.0.0.0:*                   LISTEN      /rpcbind
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:               0.0.0.0:*                   LISTEN      /rpc.statd
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:                  0.0.0.0:*                   LISTEN      /sshd
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /python2.
tcp               127.0.0.1:               0.0.0.0:*                   LISTEN      /cupsd
tcp               127.0.0.1:             0.0.0.0:*                   LISTEN      /python
tcp               127.0.0.1:                0.0.0.0:*                   LISTEN      /master
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /sshd
tcp               127.0.0.1:              0.0.0.0:*                   LISTEN      /sshd
tcp               192.168.80.31:          0.0.0.0:*                   LISTEN      /python2.
tcp               0.0.0.0:                0.0.0.0:*                   LISTEN      /mysqld
tcp               :::                      :::*                        LISTEN      /rpcbind
tcp               :::                     :::*                        LISTEN      /python2.
tcp               :::                       :::*                        LISTEN      /sshd
tcp               :::                     :::*                        LISTEN      /python2.
tcp               :::                     :::*                        LISTEN      /cupsd
tcp               :::                      :::*                        LISTEN      /master
tcp               :::                    :::*                        LISTEN      /rpc.statd
tcp               :::                    :::*                        LISTEN      /sshd
tcp               :::                    :::*                        LISTEN      /sshd
[root@cmbigdata1 lib]# 

　　　　其实，这个问题很简单，是mysql方面的问题，要么是mysql服务没启动，要么就是你的驱动jar包没安装好。

[root@cmbigdata1 lib]# pwd
/usr/share/cmf/lib
[root@cmbigdata1 lib]# 

　建议

　　　　要将mysqld设置为开机自动启动：

　　chkconfig mysqld on

 

 

 

　　可能还会出现情况，就是JDBC driver cannot be found，这时把jar包复现到 /usr/share/cmf/lib 下就行了。 
　　重启cloudera-scm-server服务。 
　　等待1分钟，访问7180端口，应该就不会出问题了。