5、启动spark，Spark Thrift Server启动失败，抛出异常
问题7：jvm启动失败 ，报-Xloggc配置有问题
通过ambrai页面，将启动的组件对应的config—>Advanced的env进行修改，去除掉-Xloggc配置。
6、连接hive失败
ExecutionFailed: Execution of '! beeline -u'jdbc:hive2://c5-ibmpower-sv011:10015/default'
7、时钟同步
添加定时任务
crontab -e
*/10 * * * * /usr/sbin/ntpdate 10.19.244.52
8、
The reported blocks 0 needs additional 42blocks to reach the threshold 0.9900 of total blocks 42.
The number of live datanodes 3 has reachedthe minimum number 0. Safe mode will be turned off automatically once thethresholds have been reached.
步骤1执行命令退出安全模式：
先切换到hdfs：su –hdfs
再执行：hdfs dfsadmin -safemode leave
步骤2执行健康检查，删除损坏掉的block。hdfs fsck / -delete
9、
Permission denied: user=root,access=READ_EXECUTE, inode="/app-logs/hive":hive:hadoop:drwxrwx---
Sudo –u hdfs hdfs fsck /
10、
org.apache.hadoop.hbase.util.FileSystemVersionException:HBase file layout needs to be upgraded. You have version null and I wantversion 8. Consult http://hbase.apache.org/book.html for further informationabout upgrading HBase. Is your hbase.rootdir valid? If so, you may need to run'hbase hbck -fixVersionFile'.
删除：apps/hbase/data目录下的数据，重启hbase
