You should be fine.  By design, Cloudera Manager does not remove any data from CDH.  To rebuild, you would basically add the services that you had before and choose the same locations for data that you had previously.  As mentioned, you could certainly use the 6-month-old database, too... CM will upgrade it the first time it starts.   Either way, your HDFS will not have been touched by the process of reinstalling Cloudera Manager and readding the services. You will need to regenerate credentials after configuring Kerberos as the keytabs are stored in Cloudera Manager's database.  That will also not impact data, but it is another task you will need to perform.   Ben ... View more

It appears that the hostname configured for db access may be incorrect:   Caused by: java.net.UnknownHostException: ODC-HADOOP-MN     at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)     at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:901)     at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1293)     at java.net.InetAddress.getLocalHost(InetAddress.java:1469)     ... 48 more   But then we also see:   Caused by: java.sql.SQLException: Schema version table SCHEMA_VERSION exists but contains no rows.     at com.cloudera.enterprise.dbutil.DbUtil.getSchemaVersion(DbUtil.java:238)     at com.cloudera.enterprise.dbutil.DbUtil$1SchemaVersionWork.execute(DbUtil.java:177)     at org.hibernate.jdbc.WorkExecutor.executeWork(WorkExecutor.java:54)     at org.hibernate.internal.SessionImpl$2.accept(SessionImpl.java:1982)     at org.hibernate.internal.SessionImpl$2.accept(SessionImpl.java:1979)   That indicates that something went wrong during initial population of the database and now it is inconsistent.  I would recommend starting over and also sharing the scm_prepare_database.sh command and options you used. ... View more