How to rolling patch a RAC cluster with opatchauto in Oracle

Patch a RAC cluster node by node (rolling) with opatchauto, keeping the database available on the other nodes.

This patches Grid Infrastructure and RAC binaries and restarts services on each node. Run as root, one node at a time, follow the patch readme, and confirm the cluster is healthy before starting.

# Run as root on one node at a time (rolling)
cd /path/to/patch/<patch_id>
$ORACLE_HOME/OPatch/opatchauto apply /path/to/patch/<patch_id>

# Roll back on a node if needed
# $ORACLE_HOME/OPatch/opatchauto rollback /path/to/patch/<patch_id>