What is Oracle Private Cloud Appliance (PCA)? Hardware, enclaves and release lines

Oracle Private Cloud Appliance (PCA) is an engineered system: one rack that arrives from the factory with servers, storage, switches and the control software already installed and cabled. Instead of building a private cloud from separate parts, you get a single appliance that is managed as one unit.

There are two very different software generations. Always check which one you have before following any guide, because commands, interfaces and concepts do not carry over between them.

Release 3.x (X9-2, X10, X11 racks)

The 3.x documentation covers three rack configurations. According to the Concepts Guide, the X9-2 rack ships with software 3.0.1 or 3.0.2 and uses 1U Oracle Server X9-2 compute nodes; the X10 rack ships with 3.0.2-b1001356 or newer and uses 2U Oracle Server X10 compute nodes; the X11 rack uses Oracle Server X11 compute and management nodes. The docs note that, in compute capacity, one 2U compute node is comparable to two 1U nodes.

Every 3.x base rack is built in an Oracle Rack Cabinet 1242 and contains:

• 3 management nodes in a cluster. The control software is factory-installed on them, and they run the Service Enclave.
• Compute nodes that host your virtual machines (called compute instances).
• Storage: an Oracle ZFS Storage Appliance with two controllers and a disk shelf, which provides block volumes, file systems and object storage.
• Switches: two leaf switches, two spine switches and a management switch.
• Flex bays (since 3.0.1): 4-rack-unit sections that can hold extra compute or extra storage, but not both in the same bay.

Two enclaves: Compute and Service

The most important idea in PCA 3.x is the strict split into two enclaves. Each one has its own web UI, its own CLI and its own API.

• Compute Enclave: where cloud users create and run workloads. Oracle designed it for maximum compatibility with Oracle Cloud Infrastructure (OCI), so it uses the same ideas: tenancies, compartments, virtual cloud networks (VCNs), instances, images and shapes. You use it through the Compute Web UI (documented as https://console.pca-name.domain), the standard OCI CLI, or the API.
• Service Enclave: where the appliance itself is administered: hardware and capacity, service delivery, monitoring, upgrades and support tools. It runs on the three management nodes and is reached through the Service Web UI (documented as https://adminconsole.pca-name.domain), the Service CLI or the Service API, which is specific to PCA.

The documentation uses these addresses for the two web interfaces and the API reference (replace the appliance name and domain with yours):

Compute Web UI:        https://console.pca1.example.com
Compute API reference: https://console.pca1.example.com/api-reference
Service Web UI:        https://adminconsole.pca1.example.com
Service API reference: https://adminconsole.pca1.example.com/api-reference

The enclaves are isolated on purpose. Oracle’s documentation states that an administrator with full Service Enclave access has no permissions at all in the Compute Enclave. The appliance administrator creates a tenancy and its first user, but cannot see what is inside that tenancy. Cloud users, in turn, have no control over the hardware.

Release 2.x (older racks)

The 2.x line (for example release 2.4.x on X8-2 and earlier hardware) works differently. Per the 2.4.3 Administrator’s Guide, compute nodes run Oracle VM Server 3.4.x, virtual machines are managed in Oracle VM Manager (a WebLogic application on the management nodes), and a pair of management nodes runs in an active/standby cluster. The appliance has its own Dashboard for hardware tasks. There are no OCI-style tenancies or VCNs in 2.x.

Which guide applies to me?

• If your users log in to a console that looks like the OCI Console and use the OCI CLI, you are on 3.x. Use the 3.x documentation library.
• If you manage VMs in Oracle VM Manager, you are on 2.x. Use the 2.x documentation for your exact release.
• Within 3.x, details change between software versions. Check the release notes and use the guide version that matches the software on your appliance.

Official documentation

• Oracle PCA Concepts Guide (3.0): Enclaves and Interfaces
• Oracle PCA Concepts Guide (3.0): Base Rack Components
• Oracle PCA Administrator’s Guide 2.4.3: Concept, Architecture and Life Cycle