Scalable Distribution of Kubernetes Workloads with L4 and L7

TL;DR

Kubernetes load balancing doesn’t stop at the cluster’s service object. For publicly accessible applications, IP distribution, TLS, routing, protection features, and backend selection must work together outside the cluster. A provider-independent edge integration separates these tasks from cluster operations and supports L4 and L7 scenarios for services, APIs, and ingress architectures .

Introduction

A Kubernetes service can make a workload accessible internally but does not automatically meet the requirements of a public endpoint. External traffic requires a stable entry point, robust distribution to backends, and clear responsibilities for TLS, routing, and failure situations. Often, this function is entirely tied to the respective Kubernetes provider or a single cluster. This simplifies the initial setup but complicates later provider changes, multi-cluster architectures, and centralized control of security-relevant functions. Kubernetes load balancing should therefore be seen as an interplay between internal cluster routing and a preceding edge. L4 and L7 fulfill different tasks and must be used appropriately according to the protocol and application.

1. L4 and L7 Address Different Traffic Layers

L4 load balancing operates at the transport layer. Connections are distributed based on IP addresses and ports without evaluating the application’s content. This is suitable for TCP or UDP-based services, databases with public access concepts, proprietary protocols, or TLS connections that are terminated only at the backend. In these cases, the edge does not need to understand HTTP structure but must reliably forward connections to reachable backends.

L7 load balancing, on the other hand, operates at the application layer. For HTTP and HTTPS services, routing can be done based on hostnames, paths, or other request properties. This allows multiple APIs and web applications to be distributed over a common public address. TLS termination at the edge relieves backends and centralizes certificate and connection logic. The choice between L4 and L7 is therefore not merely a product decision: it determines where protocol understanding, encryption, and routing rules are handled.

2. Kubernetes Ingress Needs a Stable Public Entry

Kubernetes Ingress describes rules for HTTP and HTTPS routing but is not itself a complete global entry point. The specific implementation depends on the ingress controller used, the network connection, and the cluster operation. In an L7 scenario, the ayedo Edge Cloud can accept public traffic, terminate TLS, and forward requests to Kubernetes backends based on defined routing information. The ingress remains part of the application architecture, while the edge takes over the upstream access and distribution.

For pure TCP or UDP services, an ingress is unsuitable. Here, the service is made accessible via L4 and distributed to corresponding backend endpoints. This separation prevents an HTTP concept from being applied to inappropriate protocols. At the same time, the cluster remains interchangeable: the backends can come from ayedo Managed Kubernetes , a self-hosted cluster, or a Kubernetes cluster from another provider.

3. Provider Independence Reduces Architectural Coupling

If public access is realized solely through a cluster provider’s mechanism, DNS, external IPs, TLS, routing, and failure behavior are often closely tied to this operation. Changing providers or adding a second cluster then becomes a migration task for public traffic. A separate edge layer decouples these functions from the lifecycle of individual Kubernetes clusters.

The ayedo Edge Cloud utilizes Anycast-based Layer-4 and Layer-7 load balancing, Anycast DNS, and multi-provider DNS. Backend cloaking prevents the actual backend addresses from serving as direct public access. Health checks and failover allow unreachable backends to be removed from distribution. This is particularly relevant for multi-cluster or hybrid scenarios: routing and protection functions remain centrally controllable at the edge, while workloads can be shifted between clusters or providers. The edge thus becomes the stable contract with clients, not the individual cluster.

4. Scaling Encompasses Traffic, Workloads, and Operations

An edge can distribute incoming connections and requests but does not replace Kubernetes mechanisms for scaling pods. Horizontal pod autoscaling, rollouts, and internal service discovery remain tasks of the cluster. The edge, however, must recognize which backends are reachable and where public traffic may be forwarded. Proxy protocol can pass necessary information about the original connection to compatible backends.

For operations, it is crucial to monitor these layers separately. Traffic and usage statistics at the edge show the development of public access; Kubernetes metrics show pod utilization, replica count, and internal errors. DDoS protection, web application firewall, and TLS termination belong to the upstream protection and processing layer, not the pod logic. Through a distributed multi-PoP architecture, its own autonomous system, and an active-active principle, the public entry is also considered independent of the availability of a single cluster location.

Practical and Architectural Scenario

A company operates a web application and several APIs in two Kubernetes clusters with different providers. HTTP and HTTPS requests are distributed at the edge via L7 based on hostname and path. A TCP-based service receives a separate L4 endpoint. Both clusters remain responsible for their internal services, deployments, and autoscaling rules.

If a backend fails, health checks remove it from active distribution. The public DNS and routing structures do not need to be adjusted to the respective provider. Alternatively, each cluster could operate its own external entry. However, this would distribute configurations for TLS, protection, monitoring, and failover multiple times and draw the provider change more strongly into public operations.

FAQ

Is Kubernetes Ingress the same as L7 Load Balancing?

No. Ingress typically defines HTTP and HTTPS routing in the Kubernetes context. L7 load balancing is the overarching application layer where requests are analyzed and distributed.

When is L4 Load Balancing the Better Choice?

When TCP or UDP is to be transported, the traffic is not HTTP-based, or TLS termination must deliberately remain at the backend. L4 does not require an understanding of application content.

Does Kubernetes Have to Be Operated by ayedo?

No. The ayedo Edge Cloud can also be used in front of your own Kubernetes clusters or clusters from other providers. The edge functions thus remain separate from the chosen compute operation.

Conclusion

Kubernetes load balancing should not be reduced to the question of which service opens a port. L4 and L7 form different integration paths for protocols, APIs, and ingress architectures . A provider-independent edge separates public access, protection, and routing from the actual cluster operation. The ayedo Edge Cloud supports this separation with Anycast distribution, DNS, backend health checks, and failover for Kubernetes workloads independent of the chosen provider.