Compatibility with Oracle Cloud Infrastructure
To allow you to consume core Oracle Cloud Infrastructure services within your on-premises network, and migrate workloads between your public and private cloud infrastructures with minimal or no modification required, Private Cloud Appliance offers API compatibility with OCI.
Private Cloud Appliance can be considered a rack-scale deployment unit of OCI, aligned with the physical hierarchy of the public cloud design.
|
Hierarchy Concept |
Oracle Cloud Infrastructure Design |
Private Cloud Appliance Mapping |
|---|---|---|
|
Realm |
A Realm is a superset of Regions, and the highest physical subdivision of the Oracle cloud. There are no cross-realm features. OCI currently consists of a Realm for Commercial Regions and a Realm for Government Cloud Regions. |
The concept of a Realm exists in Private Cloud Appliance, but it has no practical function. It allows the appliance to participate in any Realm. |
|
Region |
A Region is a geographic area. An OCI Region is composed of at least three Availability Domains. It is possible to migrate or replicate data and resources between Regions. |
Private Cloud Appliance is designed as a single Region. Because this private region is disconnected from any other systems, it has no practical function. Domain and system identifiers are used in system configuration instead, and mapped to the region and realm values. |
|
Availability Domain |
An Availability Domain consists of one or more data centers. Availability Domains are isolated from each other; they have independent power and cooling infrastructure and separate internal networking. A failure in one Availability Domain is highly unlikely to impact others. Availability Domains within the same region are interconnected through an encrypted network with high bandwidth and low latency. This is a critical factor in providing high availability and disaster recovery. |
Each Private Cloud Appliance is configured as an Availability Domain. Multiple installations are distinct from each other: they do not function as Availability Domains within the same region. |
|
Fault Domain |
A Fault Domain is a grouping of infrastructure components within an Availability Domain. The goal is to isolate downtime events due to failures or maintenance, and ensure that resources in other Fault Domains are not affected. Each Availability Domain contains three Fault Domains. Fault Domains provide anti-affinity: the ability to distribute instances so that they do not run on the same physical hardware. |
Private Cloud Appliance adheres to the public cloud design: each Availability Domain contains three Fault Domains. A Fault Domain corresponds with one or more physical compute nodes. |
Private Cloud Appliance also aligns with the logical partitioning of OCI. It supports multiple tenancies, which are securely isolated from each other by means of tunneling and encapsulation in the appliance underlay network. Tenancies are hosted on the same physical hardware, but users and resources that belong to a given tenancy cannot interact with other tenancies. In addition, the Compute Enclave – which refers to all tenancies collectively, and to the cloud resources created and managed within them – is logically isolated from the Service Enclave, from where the appliance infrastructure is controlled. Refer to Enclaves and Interfaces for more information.
The Compute Enclave interfaces provide access in the same way as OCI. Its CLI is identical while the browser UI offers practically the same user experience. API support is also identical, but limited to the subset of cloud services that Private Cloud Appliance offers.
The consistency of the supported APIs is a crucial factor in the compatibility between the public and private cloud platforms. It ensures that the core cloud services support resources and configurations in the same way. More specifically, Private Cloud Appliance supports the same logical constructs for networking and storage, manages user identity and access in the same way, and offers the same compute shapes and images for instance deployment as OCI. As a result, workloads set up in a private cloud environment are easily portable to Private Cloud Appliance and vice versa. However, due to the disconnected operating mode of the private cloud environment, workloads must be migrated offline.