Review this information to perform rolling upgrade of Oracle Grid Infrastructure.

• Upgrading Oracle Grid Infrastructure from an Earlier Release
  Complete this procedure to upgrade Oracle Grid Infrastructure (Oracle Clusterware and Oracle Automatic Storage Management) from an earlier release.
• Completing an Oracle Clusterware Upgrade when Nodes Become Unreachable
  If some nodes become unreachable in the middle of an upgrade, then you cannot complete the upgrade without user intervention.
• Joining Inaccessible Nodes After Forcing an Upgrade
  You can add inaccessible nodes to the cluster after a forced cluster upgrade.
• Changing the First Node for Install and Upgrade
  If the first node becomes inaccessible, you can force another node to be the first node for installation or upgrade.