Aviatrix Blog 
The concept of deploying applications with a lightweight container runtime, which has been around for a long time, was brought into the cloud-native world by Docker. But there were limitations that required developers to manually package each separate container for different environments. For applications with hundreds or thousands of containers, this creates an unmanageable level of complexity. A team at Google developed Kubernetes to automate the deployment, scaling, and management of these containerized applications.
Because Kubernetes was designed to run distributed systems, networking is a core part of the platform. The Kubernetes network model defines how containers, pods, and services communicate across a range of environments. Today, Kubernetes has become the de facto standard container orchestration tool, which means it is also the de facto standard for container networking.
Understanding the components of Kubernetes networking
In short, Kubernetes containers are grouped in pods that run on nodes in clusters:
- Container: A self-contained application that includes all the code and dependencies required to run independently.
- Pod: Includes one or more related containers that share network resources and storage, run together, and can be managed as a unit.
- Node: A physical or virtual machine that runs containers within the pods.
- Cluster: A group of nodes that work together to run the containerized applications.
Clusters are managed by the control plane, which directs operations across nodes. The control plane is the “brain” of the system. A container network interface (CNI) is a standard specification for dynamically configuring networking resources, managing how pods communicate and bridging the container and the underlying network. A service mesh automates the discovery of resources on a network and can provide some network observability and security functionality. Most production clusters use CNIs and a service mesh.
Agile and scalable by design
Kubernetes is fundamentally a developer’s platform designed for rapid deployment, scale, and updating of applications. By automating container management, organizations can speed development and respond faster to evolving requirements. The emphasis on agility and scale is clear by the sheer number of capabilities built into Kubernetes supporting these characteristics, including container orchestration, microservices support, infrastructure-agnostic deployment, hands-off scalability, self-healing mechanisms, continuous integration and continuous delivery (CI/CD) pipeline integration, and more.
The challenge of security in Kubernetes networking
This is not to say that security has been completely ignored in Kubernetes networking. CNIs can implement measures via plugins that, for example, enforce network policy by allowing you to control which pods can communicate, encrypt data in transit, or provide some anomaly detection monitoring. A service mesh provides security capabilities like encryption, authentication, authorization policies, and others to help protect sensitive data and ensure that only authorized services can communicate.
However, it’s important to note that while CNIs and service meshes provide in-cluster security and networking, they lack the feature set, outside of some fairly basic constructs, to integrate with the wider network beyond Kubernetes. They:
- Don’t scale efficiently across multiple clusters and cloud environments.
- Rely on IP-based security models for IaaS connectivity, which break in highly dynamic environments.
- Can’t provide visibility and enforcement for hybrid and multicloud connectivity.
So, while Kubernetes is designed for distributed environments, the traditional Kubernetes security solutions and controls are not, hampering the very agility and scale that Kubernetes was architected to provide.
Boost security while preserving agility and scale with Aviatrix Kubernetes Firewall
The Aviatrix Kubernetes Firewall provides multi-cluster, multicloud security to protect Kubernetes workloads across AWS, Azure, Google Cloud, and on-premises environments. The solution integrates with Kubernetes and offers fast reconciliation for ephemeral workload cycles and Kubernetes attributes. With Aviatrix Kubernetes Firewall, getting visibility and applying network-level policy to both Kubernetes and non-Kubernetes resources is dynamic and much easier to manage than traditional Kubernetes security solutions. It provides a cloud-native, scalable, and centralized approach to Kubernetes security, addressing gaps left by traditional CNIs and service meshes with:
- Advanced NAT that resolves IP exhaustion issues and enables seamless cross-cluster communication.
- Granular identity-based security that ensures security policies are enforced using Kubernetes-native identities—pods, namespaces, and services, for example—instead of relying on IP addresses.
- Hybrid and multicloud visibility with deep observability, anomaly detection, and real-time policy enforcement.
- Seamless Kubernetes-to-VM security integration for unified security across containerized workloads and legacy applications, ensuring consistent policy application and communication between VMs and Kubernetes clusters.
- Egress traffic control and policy enforcement to ensure that only authorized applications can communicate externally, helping to maintain compliance with PCI-DSS, HIPAA, and SOC 2.
- Centralized control plane with automated security policy management and orchestration which allows security teams to define, manage, and enforce policies across multiple clusters and clouds.
- Network segmentation leveraging the Kubernetes Resource Model (KRM) constructs to define and enforce segmentation policies, ensuring security is embedded in Kubernetes manifests and automated through GitOps and infrastructure-as-code workflows.
Aviatrix Kubernetes Firewall delivers a simplified, secure, and scalable cloud infrastructure, so you can enforce consistent security policies, maintain compliance across hybrid environments, and optimize operations without sacrificing agility or innovation.
Learn more about Kubernetes network security
- Blog: Three Reasons to Use Multicloud Kubernetes Networking to Secure and Scale Clusters
- Blog: Tackling Kubernetes IP Exhaustion and Overlap
- Video: Anirban Sengupta, Aviatrix CTO & SVP of Engineering, sits down with Rob Strechay and Savannah Peterson at KubeCon NA 2024 to talk about Kubernetes and the rise of multicloud networking
Schedule a demo to explore how the Aviatrix Kubernetes Firewall can strengthen your Kubernetes network security.