What is cloud-native networking?
As we’ve become more reliant on cloud computing, cloud-native network functions (CNFs) have replaced traditional physical equivalents, offering greater scalability, flexibility, and automation for cloud-native applications.
Going beyond the capabilities of more complex network functions provided by virtual machines, CNFs have had a big impact, shifting the focus from hardware-based network components to software-based network functions. They are a far more scalable solution that can better support the way cloud-based applications work and allow organisations to truly optimise their network infrastructure.
What are the key components of a cloud-native network?
CNF architecture comprises microservices (small, self-contained units that perform specific tasks); containers (which house the dependencies and libraries to run the microservices); and control, data, and management planes (for controlling network functions, processing network traffic, and managing the CNF’s life cycle respectively).
To automate deployment, scale, and manage those containerised microservices, you need an orchestration tool. And that’s where Kubernetes comes in. A tool like Kubernetes can optimise the resources allocated to the CNF and integrate it with your underlying cloud infrastructure.
What are the benefits of a cloud-native network?
It’s easy to see why many organisations are choosing CNFs for their cloud-native environments. Firstly, because they use a microservices architecture, they’re more resilient and scalable. You can develop, deploy, and manage network functions independently of everything else, scaling swiftly to adapt to workloads and reducing the impact of any failures too.
With super-fast service delivery and support for a DevOps approach, a cloud-native network means you can innovate faster, continuously improve, respond to market demands, and make the most of any new opportunities.
And because CNFs are platform-agnostic—meaning you can deploy them across public, private, and hybrid cloud environments —they offer the flexibility most organisations need.
Not to mention the fact you can reduce your data centre footprint (and associated power-guzzling hardware and labour costs) by making the most of cloud-native infrastructure.
Kubernetes networking
Kubernetes networking is one of the key cloud-native network technologies, allowing organisations to orchestrate CNFs by automating deployment, scaling, and management. Networking is central to Kubernetes, and its own network model—which includes best-practice network policies, design, and ingress controllers—helps with the management of network traffic, security, and routing.
There are four key networking problems involved in implementing a Kubernetes network model:
- Container-to-container communications
- Pod-to-pod communications
- Pod-to-service communications
- External-to-service communications
To solve these issues, the model specifies a number of practices, including:
IP allocation
When machines are being shared between applications, you have to ensure two apps aren't trying to use the same ports, but doing this at scale is a complex business. As Kubernetes can spin up thousands of pods at a time, it’s important that there are a sufficient number of IP addresses available to avoid pod scheduling delays.
With the Kubernetes networking model, every pod in a cluster gets its own unique IP address, so you don’t need to create links for pod-to-pod communication—pods can easily communicate with each other in a cluster. Each container within a pod shares the same IP address so that they can communicate freely with each other too.
This means pods act like virtual machines (VMs) or hosts and are more like processes running within a VM, making it much easier for apps to be migrated from VMs and hosts to Kubernetes-managed pods.
Network policies
The Kubernetes network model also incorporates network policies that control traffic flow at the IP address or port level rather than using the network’s structure. This is vital—think of it like a firewall in a more traditional network setup. Without these policies, all pods within a cluster can communicate with each other by default—imagine the implications for pods containing sensitive data!
These rules specify communication within the cluster as well as with the outside world, restricting pod communication (isolation) and preventing the network from becoming too complicated. They can isolate network traffic across those pods in a dev environment from those in production.
Steering the ship: keep on top of containerisation with Kubernetes
In this eBook, we’re going to provide a quick recap to put Kubernetes in context; explore the key challenges it helps your business solve, including how it can support you as you scale; look at the benefits containerisation can bring; and also ask whether it’s the right solution for your organisation.
What is Calico Kubernetes?
So, how do you implement this model? You're going to need a Kubernetes network provider that supports network policies. There are several third-party tools on the market, including Calico. This open-source policy engine enables scalable networking incorporating Kubernetes security and network policies.
As a container networking interface (CNI) recommended by many leading managed Kubernetes solutions, Calico extends Kubernetes' features, allowing network policies to be applied to any object with rules that contain specific actions. It lets you use ports, port ranges, protocols, IPs, and more as the source or target for these rules, and it offers more control over traffic flows.
Kubernetes networking challenges
With Kubernetes becoming more embedded across production, security, and infrastructure, there are some common challenges you'll need to watch out for. For starters, Kubernetes networking is more dynamic than traditional networking, which might make securing your network difficult, with many IP addresses to consider and control. However, managed solutions, cloud-native services, and platforms make Kubernetes networks more secure overall.
You'll need to consider the resource demand and error-prone process of defining and changing network policies (that's where solutions like Calico can help make a big difference). Complexity is also an issue as you scale your Kubernetes network, as is communication. You can make the most of routing, visibility, and failure handling features offered by service mesh solutions to help overcome the former. At the same time, careful management and monitoring of your network policies can address the latter.
Can't get enough of Kubernetes?
You're in the right place if you're looking for more Kubernetes content to help clue you up and empower your cloud-native journey. Download our ebook, Steering the Ship: Keep on top of containerisation with Kubernetes, today!
And if you're just getting started and want advice and support to kickstart Kubernetes or a cloud-native approach, get in touch.
