How does a RAC DB 'spread' from single instance to multiple instances ?

Question

GI/RDBMS Version: 11.2.0.3
OS: Oracle Linux 6.3
Filesystem : ASM
When a RAC database is created using dbca , Manually , or RMAN restore, the DB is created in the Node1 first with cluster_Database=FALSE .
Then you run the following commands (for 3-node RAC)  from Node1
srvctl add database -d lmnprod -o $ORACLE_HOME -p +LMNPROD_DATA01/lmnprod/spfilelmnprod.ora
srvctl add instance -d lmnprod -i lmnprod1 -n hwcarser290
srvctl add instance -d lmnprod -i lmnprod2 -n hwcarser291
srvctl add instance -d lmnprod -i lmnprod3 -n hwcarser292
Once the DB is created,mounted and opened in Node1 and the above commands are executed , you set cluster_Database=TRUE and startup the Instance2 and Instance 3 in Node2 and Node3.
I just want to know how does Node2 and Node3 becomes aware of the DB and joins the DB cluster ? What happens internally ?

Answer 1

Generally speaking, registering in OCR is not required for database to be a cluster database.
Migration from single-instance database to cluster consists of creating redo logs and undo tablespace for new instance and enabling this instance (thread). If database is policy-managed, this is done automatically for new node.