If you want to restart any host which is in a cluster first, you have to stop Oracle and cluster resources.
1. Stop instance ---> $srvctl stop instance -d <db_name> -i <Instance_name>
2. Stop ASM instance ----> $srvctl stop asm -n <node_name>
3. Stop Nodeapps services ---> $srvctl stop nodeapps -n <node_name>
4. Stop CRS ---> $crsctl stop crs (should be run as root user or oracle user should have SUDO permission)
Finally Check the status of the resource
All resource should be in OFFLINE.
For startup, follow the Bottom up approach for above said shutdown procedure