When applying an Oracle-provided patch to an Exadata Database Service instance via the Oracle Cloud Infrastructure (OCI) console, the process is designed to be comprehensive and maintain high availability. The patch bundles typically include updates for the operating system (OS), Grid Infrastructure, and database software. The update is applied to the database (compute) nodes in a rolling fashion, meaning one node is patched and restarted at a time. This strategy ensures that the database service remains available throughout the process, thus minimizing downtime. The patching of the storage server nodes is a separate, distinct operation also managed from the OCI console.

A. Exadata patches are full-stack and include necessary OS updates to maintain a certified and supported environment. The OCI console manages the application of these comprehensive patches.

B. Patching all nodes concurrently would cause a complete system outage, which contradicts the high-availability architecture of Exadata. The process is explicitly designed to be rolling.

D. The OCI console provides a unified interface for patching all major components of the Exadata service, including the database nodes' OS, not just the storage servers.

1. Oracle Cloud Infrastructure Documentation, "Update the Operating System on a Virtual Machine": "You can update the operating system of the virtual machines in a VM cluster... The update process is a rolling one, with only one virtual machine cluster node being taken offline at a time. This ensures that the cluster is continuously available during the update process." (This confirms the rolling update of the OS on database nodes to minimize downtime).

2. Oracle Cloud Infrastructure Documentation, "Updating an Exadata Cloud Infrastructure System": "You can update the database servers and the storage servers in your Exadata Cloud Infrastructure system... You can update the database servers by applying a patch to the Grid Infrastructure, and you can update the storage servers by applying a patch to the Exadata system software." (This confirms that database servers and storage servers are updated as separate operations).

3. Oracle Cloud Infrastructure Documentation, "Patch a Grid Infrastructure Deployment": "The patching process is a rolling one, with only one node being taken offline at a time." (This reinforces the rolling nature of the update process for the database nodes, which host the Grid Infrastructure).