Cloud-Native technology is the most effective technology in continuously building and operating the world's largest cloud applications. Being cloud-native is the approach to build and run applications that take advantage of the cloud computing model. Cloud-native Applications are a set of small, independent, and loosely coupled services. These are the applications built using the cloud computing model to improve the quality and increase speed and flexibility while reducing deployment risk. It is an approach that focuses on how the applications are built, deployed, and managed. No wonder why the introduction of Cloud-Native Network Traffic Management in Cloud-Native Applications was the need of the hour!
If an app is termed as "cloud-native," it clearly specifies that it is designed to supply an automatic, uniform development and management experience across different clouds, be it private, public, or hybrid. A cloud-native application uses a set of tools that simplify and manage the orchestration of application services. These services, individually, are deployed as containers and connected through APIs. The containers are then orchestrated by a container scheduler responsible for managing where and when a container should be provisioned into an application.
Cloud-Native Development Architecture
Organizations adopt the cloud computing model to extend the scalability and availability of apps. These benefits are achieved through on-demand provisioning of resources and automation of the application life cycle from development to production. But to completely utilize these benefits, a new sort of development is required. Cloud-native application development fulfills this requirement. It is an approach to build and update apps quickly while continuously improving the quality and reducing the risk. More specifically, it’s an approach to create and run responsive, scalable, and fault-tolerant apps anywhere—be it public, private, or hybrid clouds. <image> Cloud-native applications are designed to be portable to different deployment environments: public, private, or hybrid cloud. DevOps and CI/CD are used to automate building, testing, and deploying services into the production network. Let's discuss the development processes below:
Microservices architecture structures an application to collect independent and loosely coupled services to implement business capabilities. Deploy, scale, and upgrade each microservice in individual containers, independent of other application services. It enables continuous delivery and continuous deployment of large and complex applications.
Containers are a form of virtualization. An OS instance is divided into multiple isolated containers, having individual writable filesystem and resource quota. So containers actually use an Operating System-level of virtualization. They can be deployed on bare metal as well as virtual machines. Each microservice is generally deployed in a separate container; however, multiple microservices can also be deployed per container as per the application and performance requirements.
Continuous Delivery Offerings
The adoption of continuous delivery has revolutionized the speed to market. It makes releases easy and reliable, enabling the organizations to deliver frequently and at a lesser risk factor. It is all about making an individual application modification ready for release without even waiting to bundle it up with other release changes. The use of continuous delivery provides immediate feedback from end-users to developers.
Empowering DevOps Best Practices
DevOps is a technology that combines development and operations into a single IT value stream by utilizing agile and lean software development techniques. It enables organizations to apply continuous integration and continuous delivery services to build, test, and deploy software more rapidly and iteratively. Therefore, we can say that Cloud-native technologies provide the basic building blocks to build applications that achieve the goal of reducing OpEx by simplifying and automating the network operations, allowing the provisioning of faster services to market and deploying across a broad range of cloud environments.
Why Cloud-Native Networks?
Consider Cloud-Native Networks as a revolution in network design and architecture. Like the development of cloud-native applications, cloud-native networks also run their services like security inspections, route calculation, and policy enforcement on a platform that takes full advantage of cloud attributes. There are no proprietary appliances used, which changes the technical and operational characteristics of enterprise networks. The platform used for such networks has a multitenant design, operates on off-the-shelf servers, and can provide a breakthrough performance that was earlier only possible with customized hardware usage.
Cloud-Native Networks: The Common Myths
The cloud-native network is not simply referred to as the porting of software or hosting an appliance over the cloud. In fact, it is a network that is built with the cloud service from scratch. Cloud-native networks do not follow the stale process of traditional network service providers. Instead, they avoid the cost overhead and greatly impact enterprise-wide, which can be understood better by considering the five attributes below.
Attributes of Cloud-Native Network Services
The attributes explained below are important factors that must be satisfied if a provider’s software and network platform are to be considered cloud-native:
Scalability is one of the most important characteristics of cloud-native networks, just like cloud-native applications. They have no scaling limitations. The software stack is designed to take advantage of additional compute, memory, networking resources, and storage. New traffic loads or requirements can be easily accommodated to the network platform.
Efficiency is another attribute that is highly promoted by cloud-native network services. The design of cloud-native networks provides high network quality and performance at low costs. Third-party license fees, as well as nominal support costs, are eliminated because of platform ownership. Costs incurred on the construction and maintenance of physical transmission networks are eliminated using a smart software overlay that constantly monitors the underlying network providers and selects the most optimum one for every packet being transmitted. As a result, we are provided with a carrier-grade network at an unmatched cost and performance.
Multitenancy refers to the abstraction of the underlying infrastructure to provide a private network experience to every customer. It is the network provider who is responsible for maintaining and scaling the network infrastructure. Similar to any other cloud storage and compute, cloud-native networks also do not have any idle appliance. Multitenancy allows the maximization of the underlying network infrastructure.
This attribute refers to the rapid innovation and instant availability of new features and capabilities. All the customers are instantly benefitted from the most recent feature set. Using their own software platforms, cloud-native network providers can easily and rapidly expand their networks to new regions. Even troubleshooting in cloud-native networks takes very little time as the support and platform development teams operate together.
Cloud-native networks are accessible using mobile clients, physical and virtual appliances, and third-party IPsec compatible edges. Ubiquity refers to the connection of one network to any resource from anywhere. It states that the enterprise network should be available everywhere and accessible from any resource, be it physical, cloud, or mobile.
Introduction to Network Functions
Routers, firewalls, and campus switches -- these physical devices are common examples of Network Functions (NF) used for processing the packets that support a network or application service. The performance, features, operational control, and scale differ from one device to the other. A network is formed when a topology consists of similar interconnected NFs. And when such networks are interconnected to form larger networks, they are characterized by a broad range of services, applications, and heterogeneous activities. This kind of network model, which uses physical network infrastructure, can be seen anywhere, all the way from the Internet to even residential wifi networks.
For operators, it is the ability to virtualize network functions, utilizing new architectures (NFV, SDN) built into 5G systems that will be deployed as part of the overall network. Source: Forbes
A Virtual Machine (VM) can be called the software version of a physical server machine. It has got quite a few advantages that include:
Configurations using VM management systems
Cost savings due to the hardware decoupling of Network Functions (NF).
Apart from these advantages, a disadvantage is that there is an overhead required to emulate all the software and hardware functions run on physical servers into a complete software. If the applications and network functions are running on dedicated physical servers, they are considered bare metal. Seems to define a VNF, right?
Virtualized Network Function (VNF)
A Virtualized Network Function (VNF) is an NF designed for virtualized environments. VNFs run in VMs and are connected to a virtual overlay network that runs on top of a physical underlay network. VNFs constitute all the features and functions of dedicated hardware NFs excluding performance and scalability.
Benefits of VNF
VNFs can be easily pre-staged to handle the increase in traffic workloads.
Use of VNF offers service chaining, i.e., a set of interconnected VNFs can be easily used to assemble a uniform customer application.
There is a good understanding of performance and scalability requirements, just like any other network environment.
Also, the network operations and architecture are very similar to physical networks due to which users who have worked with physical networks do not find difficulty in working with VNFs.
Challenges in VNF Adoption
Impact in performance due to the overhead caused by VM software
Long boot times even during normal maintenance and failure restart; burst scenarios impact the availability.
During scale-out, VNF requires investment over additional servers and network gears.
The VM resources can also potentially sit idle.
VNF resource allocation is not precise enough to meet the traffic workload demands.
VNF is considered as a single atomic unit for development, testing, deployment, and troubleshooting. This means that VNF is implemented as code monoliths, which adds complexity.
What areCloud-Native Network Functions? (CNF)
Cloud-Native Network Functions (CNF) are those network functions that are designed to run inside containers. CNFs are the cloud-native networks that inherit all the operational and architectural principles of cloud computing. These principles also include the K8s lifecycle management, resiliency, observability, and agility. Some of the requirements of a CNF implementation are:
Lightweight and stateless data plane configuration to meet the cloud-native speed.
A robust and feature-rich software data plane
Userspace networking to keep kernel immutable in a CNF network for performance gains
Availability of common APIs for faster and simplified development and integration
Observability through logging and tracing for testing and operations
Advantages of CNF
So what advantages do Cloud-native Network Functions have onboard? Let's get a brief idea below:
A CNF is just a pod with special network functionality, which results in a point-to-point userspace communication channel to offer kernel-free packet transmission function.
CNFs include all the best practices that already exist in application pods. There is a lifecycle management parity with application containers that include environments for development, CI/CD, orchestration, scheduling, distributed management, and logging.
CNFs operate as durable pods but can be torn down to start up a new instance if new functions are needed. This dynamic nature already has stateful configuration management. A stateless approach is followed for the processing of configuration updates stored in an external data store.
A smaller footprint reduces resource consumption so that potential savings can be allocated to applications or infrastructure expansion.
Userspace networking helps in rapid development, innovation, and immutability of features without any interaction with the Linux kernel.
Resource efficiency and maximum throughput are contributed through userspace processing, multi-core tuning, hardware control, and kernel bypass.
CNFs are agnostic to host environments. Bare-metal is the most preferred host of choice.
CNF Solution Scenarios
Now let's discuss certain solution scenarios for Cloud-Native Network Functions to understand the topic better.
1. Load Distribution
This is one of the most inherent properties of cloud-native networking, which ensures service resiliency and scalability. CNF acts as a load balancer and can direct traffic to the backend pods of the k8s service. It can also act as a policy-based forwarder to steer traffic to an application pod. A Kube-proxy can also perform these functions, but a CNF is much suitable. It can play the role of ingress or a load balancer for flexible load distribution, observability, and maximum throughput with userspace processing.
2. Enhanced Cluster Networking
Newer CNF implementations can enable a new network service by improving existing solutions. CNI-bootstrapped L2 bridge domain provides multi-interface support to attach multiple pods to the bridge domain for inter-pod connectivity. Map the K8s service and policy traffic to a fast data plan, increasing the throughput and providing visibility into the traffic. Network Service Mesh binds interface mechanism and payloads to construct a set of continuous segments to form a vWire. It uses its own Control Plane to program x-connects for the setup of vWire.
3. Service Bundles
Arrange the Cloud-Native Network Functions into a chain of network functions that support an application or network service offering.
Cloud-Native Network Technologies
There are basically three Network Technologies driven by Cloud-Native Computing. Let's discuss them one-by-one below:
1. Cloud-managed Networks
These networks centrally configure and manage secure and remotely deployed enterprise-wide wired and wireless connectivity through the provision of a cloud-based web portal. CMNs are continuously expanding to include wired connectivity, WLAN access points, WAN security appliance management, and datacentre networking. CMNs benefit organizations with limited IT staff and budget, wanting to quickly activate remote branches with limited on-site technical staff and more remote management. However, this remains less suitable for large enterprise sites that have complex LAN and WLAN infrastructure.
2. Service Mesh Adoption
It is an adoption of distributed computing hardware to optimize communication between application services. This adoption provides a lightweight medium for service-to-service communication. It also provides a proxy for the same and supports functions like encryption, authentication, service discovery, authorization, load-balancing. Self-healing and request routing. It is suitable for delivering microservices and mini-services operations. The adoption of a service mesh is evolving at a very rapid rate. Its evolution is actually tied to the increase in the adoption of containerization and microservices. Service mesh adoption is considered important as traditional technologies prove to be really heavy for microservice communication. Istio, an open-source project, is provided as a service mesh framework for the microservices running on Kubernetes.
3. Kubernetes Networking
This networking technology for cloud-native applications enables communication among the pods and services on a Kubernetes cluster. Additionally, Kubernetes networking software enables IP address management, policies, and multitenancy. A CNI plugin is used to handle communication within the Kubernetes pod, and an ingress controller is used for the same with the outside world. The rise in the need for Kubernetes networking is directly proportional to the adoption of containers, growing rapidly.
Istio: A Popular Service Mesh
Istio is a service mesh framework that meets the diverse deployment requirements and provides extensibility. It describes a microservices network with certain requirements, including load balancing, service discovery, monitoring, and failure recovery. It just grows in complexity and size and gets difficult to manage with its more complex operational requirements. Istio is thus a popular service mesh framework that provides cloud-native networking capabilities.
Benefits of Istio
Some of the benefits of using an Istio Service Mesh are:
Istio is a complete solution in itself, which satisfies the requirements of microservice applications.
It provides operational control and behavioral insights over the service mesh as a whole.
A special sidecar proxy is deployed throughout the environment to add Istio support, enabling interception of all network traffic between the microservices. We then configure Istio and manage it using the control plane functionality.
Cloud-Native Networking actually plays a really crucial role, especially when it comes to cloud-native environments. Cloud-native networks prove to be a revolution in network design and architecture. These are networks that are built with cloud service from scratch. Cloud-Native Networking's advent serves to establish the network as one of the most critical and prominent roles in cloud-native applications' success.