Installation of rac with a one instance possible.

1. u have to install cluster software (os scpecific) + oracle custer software without cluster manager
2. start cluster software
3. start gsd on one node only
4. start oracle insatller on one node and choose only one currrent node
5. install Oracle cluster manager on this node only
6. install Oracle database software on this node only
7. manually activate this node only, using srvctl utility and declare only one instance for this database.
8. manully install db using sqlplus (not dbca)