Oracle recommends that you use Cluster Verification Utility (CVU) to help to ensure that your upgrade is successful.

You can use CVU to assist you with system checks in preparation for starting an upgrade. CVU runs the appropriate system checks automatically, and either prompts you to fix problems, or provides a fixup script to be run on all nodes in the cluster before proceeding with the upgrade.

• About the CVU Upgrade Validation Command Options
  Review this information about running upgrade validations.
• Example of Verifying System Upgrade Readiness for Grid Infrastructure
  You can verify that the permissions required for installing Oracle Clusterware have been configured on the nodes node1 and node2 by running a command similar to the following.