While creating New databse If you are facing any of the below errors .. please follow the below solution.
db2inst1@nc184158:~/db2inst1/NODE0000/SQL00001> db2 -tf /opt/builds/DCD1321/MC/cds_db2_admin.sql
SQL1005N  The database alias "CDSDB" already exists in either the local
database directory or system database directory.

SQL1013N  The database alias name or database name "CDSDB" could not be found.
SQLSTATE=42705

DB21034E  The command was processed as an SQL statement because it was not a
valid Command Line Processor command.  During SQL processing it returned:
SQL1024N  A database connection does not exist.  SQLSTATE=08003

SQL0843N  The server name does not specify an existing connection.
SQLSTATE=08003

SQL1013N  The database alias name or database name "CDSDB" could not be found.
SQLSTATE=42705


SQL1005N The database alias "<name>" already exists

Solution

1. Db2 get dbm cfg | grep DFTDBPATH ( if unix , windows check for DFTDBPATH)
2. Db2 catalog db dbname on DFTDBPATH
3. Db2 terminate
4. Db2 drop db dbname
5. Then create db