Kubernetes has become the de facto standard for container orchestration, but its native networking capabilities face significant challenges when applied to telecom workloads. These workloads demand complex networking requirements, such as multi-network interfaces, storage isolation, and application-specific traffic segmentation. As the industry moves toward cloud-native solutions, the need for a standardized, scalable, and flexible networking framework has never been more critical. This article explores the current state of Kubernetes networking, the limitations of existing solutions, and the path toward a unified native multi-network architecture.
The Container Network Interface (CNI) is the foundational component for enabling network connectivity in Kubernetes. It defines how pods communicate within and across clusters. However, traditional CNI implementations, such as OVN-Kubernetes, often struggle to meet the advanced requirements of telecom workloads. These include the need for multiple network interfaces, isolated storage networks, and application-specific data-plane interfaces.
Telecom workloads require specialized networking capabilities, such as:
NAD provides a standardized API for attaching multiple networks to pods. While it is widely adopted, its implementation varies across CNI providers like OVN-Kubernetes and Multus. This fragmentation complicates interoperability and limits scalability.
DRA is a Kubernetes feature that allows dynamic allocation of hardware resources, including network interfaces. It operates in three phases:
DRA is expected to reach GA in version 1.134, enabling full device resource management.
Kubernetes emphasizes backward compatibility, but multi-network concepts conflict with its original flat network model. There is a need for a unified high-level API that integrates with low-level CNI implementations without introducing fragmentation.
Multiple projects (CNI, Multus, Network Plumbing Group) struggle to align on a common architecture. Network policies and service APIs require rethinking to support multi-network scenarios, such as IP allocation and policy enforcement.
Network policies rely on Pod IPs, which can lead to conflicts in multi-network environments. Services (e.g., Service CIDR) must be redefined to support multi-network CIDRs or flat network models. This complexity complicates policy enforcement and resource management.
DRA will enable dynamic allocation of network interfaces, while Cap 5075 provides capacity declaration and scheduling capabilities. Together, they will enhance resource management flexibility.
Efforts like the Paris meeting aim to standardize multi-network concepts. The goal is to unify high-level abstractions and integrate CNI with Kubernetes core functionalities to reduce fragmentation.
Services and network policies must be redesigned to support multi-network scenarios. This includes defining multi-CIDR support and ensuring policy consistency across interfaces.
The ultimate objective is to establish a native multi-network solution within Kubernetes. This will ensure end-to-end integration, cross-platform compatibility, and seamless operation across cloud, on-premises, and hybrid environments.
Network interfaces are treated as resources, managed via DRA APIs. This enables scheduling, affinity rules, and dynamic IP assignment. The three-phase process ensures alignment between node resources and pod requirements.
Multi-Net Object allows defining multiple network interfaces per pod, supporting complex topologies like multi-VPC or multi-subnet configurations. It is expected to be released in an Alpha version, with integration into Gateway API planned for future releases.
Current network policies and services operate in isolation. Future work will unify their management to avoid IP conflicts and ensure consistent policy enforcement across interfaces.
The journey toward native Kubernetes networking for telecom workloads is ongoing. While existing solutions like NAD and OVN-Kubernetes provide partial support, they lack the standardization and scalability required for complex environments. DRA and Cap 5075 represent critical steps toward dynamic resource management, while community collaboration will drive standardization. As the CNCF ecosystem evolves, the focus remains on creating a unified, flexible, and interoperable networking framework that meets the demands of modern telecom workloads.