How to add new instance manually to the Cluster and Resolve the ORA-01618 error

ALTER SYSTEM SET local_listener='(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=xxxxxx)(PORT=1521))))' SCOPE=MEMORY SID='racdb2';
ALTER DATABASE MOUNT
SUCCESS: diskgroup FBK was mounted
NOTE: dependency between database racdb and diskgroup resource ora.FBK.dg is established
ORA-1618 signalled during: ALTER DATABASE MOUNT

Error: ORA-01618 (ORA-1618)
Text: redo thread %s is not enabled - cannot mount
---------------------------------------------------------------------------
Cause: The INIT.ORA parameter "thread" requests a thread that is not
enabled. A thread must be enabled before it can be mounted.
Action: Shutdown the instance, change the INIT.ORA parameter and startup
mounting a different thread. If the database is open in another
instance then the thread may be enabled.

Starting up:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options.
ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1
System name:    Linux
Node name:      racnode2.racscan.com
Release:        2.6.32-358.14.1.el6.x86_64
Version:        #1 SMP Mon Jun 17 15:54:20 EDT 2013
Machine:        x86_64
Using parameter settings in server-side pfile /u01/app/oracle/product/11.2.0/dbhome_1/dbs/initracdb2.ora
System parameters with non-default values:
processes                = 150
sga_max_size             = 50G
...
thread                   = 2 >>>>>>>>>>>>>>>>>>>>>>>>> thread 2
undo_tablespace          = "UNDOTBS2"
instance_number          = 2




Solution :

SQL> alter database enable thread 2;