OS container object model and management interfaces: The first set of Cloud-Native VNF orchestration specifications
The ETSI Industry Specification Group (ISG) NFV has published the initial release of ETSI GS NFV-IFA 040 titled "Requirements for service interfaces and object model for OS container management and orchestration specification". This document is the first normative specification delivered for the NFV Release 4 feature on “Cloud-native VNFs and Container Infrastructure management”. The specification propagates the recommendations from the study in ETSI GR NFV-IFA 029 and formally specifies the new functions required for the management and orchestration of OS containers, the Container Infrastructure Service Management (CISM) and the Container Image Registry (CIR). The CISM is responsible for maintaining the containerized workloads while the CIR is responsible for storing and maintaining information of OS container software images.
To enable a consistent and generic system for the management of containerized VNFs, ETSI GS NFV-IFA 040 specifies an abstract NFV object model for OS container management and orchestration, including their relationship to the core information models of NFV-MANO. The abstract NFV objects are also expected to be used in specifications profiling APIs of de-facto standard solutions, to map the abstract NFV objects to objects of the specific de-facto standard solution. One of the introduced abstract NFV objects is the Managed Container Infrastructure Object (MCIO), an object managed and exposed by the CISM, characterized by the desired and actual state of a containerized workload. Managed objects from Kubernetes® such as Deployment or Service are examples which map to an MCIO. Another new NFV object is the Managed Container Infrastructure Object Package (MCIOP), a hierarchical aggregate of information objects including declarative descriptors and configuration files for one or multiple MCIOs. Helm charts as specified by CNCF® are an example which maps to an MCIOP.
Furthermore, ETSI GS NFV-IFA 040 specifies requirements on the list of services to be offered by architectural elements providing the CISM and CIR functions and on the interfaces for exposing these services to NFV-MANO and other consuming entities. The CISM shall provide services for the management of OS container workloads as well as for the management of OS container compute, storage, network resources and their configuration. The CIR shall provide a service for the management of OS container images. This document intentionally does not specify interface operations or information models but only requirements on the management service interfaces. This approach leaves further details to the specification of protocols and data models in the form of profiling de-facto standard open source solutions.
The ETSI GS NFV-IFA 040 is accompanied by the publication of the first NFV Release 4 editions of the ETSI GS NFV-IFA 010010 and ETSI GS NFV-IFA 011 specifications. The former is enhanced with functional requirements on the CISM and CIR. The CISM is required to expose OS container management service interfaces on an MCIOP and on an MCIO abstraction level. Additionally, the functional requirements on the NFVO and the VNFM are extended for consuming dedicated management service interfaces exposed by the CISM and the CIR.
The VNF descriptor and packaging specification in ETSI GS NFV-IFA 011 has also been significantly enhanced for the modelling of containerized VNFs. The VNF package is now required to support the inclusion of MCIOPs and OS container images. The VNF descriptor information model has been enhanced with a new information element for an OS container descriptor which allows to utilize the VDU as deployment template for an MCIO. Among multiple enhancements and alignments throughout the document, a new descriptor information element for a virtual connection point has also been introduced, which specifies primary container cluster external network connection properties. The addition of a descriptor information element for MCIOP profiles supports the identification and mapping of declarative descriptors included in the MCIOP with elements specified in the VNFD.
A big “Thank you” to all contributors to the new and enhanced specifications!
The publication of this first set of specifications is very important and confirms that ETSI ISG NFV can quickly embrace new technologies for cloud-native VNFs to support communication service providers with standardized, interoperable solutions. These new specifications provide a baseline for the integration of OS container management and orchestration into the NFV framework. They will be followed by extensions of the specifications of the interfaces on the main NFV-MANO reference points and complemented by requirement specifications on the container cluster management and container security.