Review these topics to patch Oracle Grid Infrastructure in different stages of installation or upgrade.

• Applying Patches Using Zero-Downtime Oracle Grid Infrastructure Patching
  Starting with Oracle Database 19c Release Update (RU) 19.8, you can keep your Oracle RAC database instances running and accessible to the database users during Oracle Grid Infrastructure patching.
• Applying Patches During an Oracle Grid Infrastructure Installation or Upgrade
  Starting with Oracle Grid Infrastructure 18c, you can download and apply Release Updates (RUs) and one-off patches during an Oracle Grid Infrastructure installation or upgrade.
• Applying Patches After an Oracle Grid Infrastructure Installation or Upgrade
  You can apply patches to Oracle Grid Infrastructure deployment in rolling mode after a successful or a failed upgrade. This mode is similar to the "Rolling Upgrade" mode in terms of the Oracle ASM operations allowed in this quiesce state.
• Applying Patches when Oracle Clusterware Fails to Start
  If the Oracle Clusterware stack does not start because of any error, then you can patch Oracle Grid Infrastructure using the OPatch utility.