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, because the upgrade script (rootupgrade.sh) did not run on the unreachable nodes. Because the upgrade is incomplete, Oracle Clusterware remains in the previous release.
• Joining Inaccessible Nodes After Forcing an Upgrade
  Use this procedure to join inaccessible nodes after a force 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.