onap.capabilities.Compute
- Anatoly Katzman
The ONAP Data Model implements the IM's ComputeDesc and MemoryDesc elements as TOSCA capabilities of the type onap.capabilities.Compute.
This capability characterizes a virtual machine. Intended to be used primarily as part of a TOSCA requirement clause. Normally, requirements of this type are never satisfied within the model. They stay “dangling” until instantiation. On instantiation, the orchestrator satisfies them out of the available inventory.
Definition
capability_types:
onap.capabilities.Compute:
description: |
When used with a requirement, describes infrastructure-level
computational power consumed by the node
derived_from: tosca.capabilities.Container
properties:
num_cpus:
description: number of virtual CPUs
type: integer
constraints:
- greater_or_equal: 1
required: false
cpu_frequency:
description: CPU clock rate
type: scalar-unit.frequency
constraints:
- greater_or_equal: 0.1 GHz
mem_size:
description: amount of memory
type: scalar-unit.size
required: false
constraints:
- greater_or_equal: 0 MB
storage_size:
description: amount of internal disk storage
type: scalar-unit.size
required: false
constraints:
- greater_or_equal: 0 MB
io_bitrate:
description: IO performance, in bits per second
type: integer
required: false
architecture:
description: vendor+architecture, for example, Intel64
type: string
required: false
custom_features:
description: |
Additional features description, serialized in a well-known format.
type: onap.datatypes.json
required: false In addtition to the obvious properties required by the IM, this capability type also includes properties that allow for easy customization:
architecture - allows the VFC vendors to focus their requirements on a specific hardware architecture, for example "Intel x86".
custom_features - an opaque container for a list of feature definitions. It is of the onap.datatypes.json data type, meaning that it is a JSON-formatted string. Can be treated as just a plain string.
Examples of requirement assignments in their simplest form:
Requirement for at least 2 vCPUs
# .. a node template, omitted...requirements:
- host:
node_filter:
capabilities: onap.capabilities.Compute
properties:
num_cpus:
- greater_or_equal: 2
Examples of requirement assignments in the combined (TOSCA properties + custom_features) form:
Requirement for at least 2 vCPUs + bunch of Intel-specific features
requirements:
- host:
node_filter:
capabilities: onap.capabilities.Compute
properties:
num_cpus:
- greater_or_equal: 2
custom_features: |
{
"simultaneousMultiThreading": true,
"simultaneousThreads": 10,
"logicalCpuPinningPolicy": "Dedicated",
"logicalCpuThreadPinningPolicy": "Prefer",
"instructionSetExtensions": ["aes", "sse", "ddio"],
"directIoAccessToCache": "dca",
"accelerator": "whatever you like",
"measuredLaunchEnvironment": "",
"secureEnclave": "",
"hypervisorConfiguration": {
"memoryCompaction": "best",
"kernelSamePageMerging": true
},
"computeRas": "pciDetectedAndCorrectedErrors"
}
In the example above the text in the custom_features property is actually a JSON document.
The hardware vendors are encouraged to provide a well-defined schema (JSON Schema for JSON-formatted texts, DTD or XML Schema for XML-formatted texts, etc) to govern syntax of their custom_feature texts. For example, a JSON schema for the CPU custom feature fron the example above may look like this:
Example of JSON Schema for CPU custom features
The idea of using a schema document together with the custom_features text seems to be very powerful. For a demostration of how such a schema would work, please visit any of the JSON schema validators available online, for example, https://json-schema-validator.herokuapp.com/. Just copy and paste over there the above JSON schema and the value of the custom_feature field and check on the validation results:
TOSCA 1.2 allows using a JSON schema as a TOSCA constraint in parameter definition and node_filter clauses. Using an external schema document (with a Web URL in the TOSCA constraint clause) seems to be especially promising, since such usage combines the benefits of schema-driven validation with the flexibility of having the schema hosted outside: