Cilium: The Reference Architecture for High-Performance Networking & Security

TL;DR

Kubernetes networking has long been a bottleneck, hindered by outdated Linux technologies (iptables). While AWS provides a solid base connectivity with the VPC CNI plugin, it quickly hits limits in security and visibility (IP-based instead of identity-based). Cilium revolutionizes this layer by using eBPF. It enables high-performance networking, transparent encryption, and deep observability (Hubble) without needing to change application code—portable across any cloud.

1. The Architectural Principle: eBPF instead of Iptables

Traditional Kubernetes networks (like the default AWS CNI or kube-proxy) are based on iptables. This is a technology from the 90s, designed for static server environments. In dynamic clusters with thousands of ephemeral containers, these tables become gigantic, increasing latency and burdening the CPU.

Cilium uses eBPF (Extended Berkeley Packet Filter). This is a technology that allows logic to be executed directly, securely, and extremely fast in the Linux kernel.

• Kernel-Level Speed: Packets are processed without the costly journey through the entire network stack.
• No Kube-Proxy: Cilium can completely replace the outdated kube-proxy and offers a far more efficient service resolution (LoadBalancing).

2. Core Feature: Identity-Aware Security (Zero Trust)

The biggest problem with traditional firewalls (and AWS Security Groups) is their blindness: they only understand IP addresses and ports. In Kubernetes, however, IP addresses change constantly.

Cilium abstracts the IP address. It works with identities (based on Kubernetes labels).

• Intent-based Policies: Instead of saying “Allow IP 10.0.1.5 access to 10.0.2.3,” you define: “Allow the Frontend service access to the Backend service.”
• Layer 7 Visibility: Cilium understands application protocols. You can not only allow port 80 but specifically regulate: “Allow GET /public, but deny POST /admin.” This is impossible with AWS Security Groups.

3. Deep Observability with Hubble

Debugging network problems in Kubernetes often resembles searching for a needle in a haystack. Cilium provides Hubble, a built-in telescope. It visualizes the entire traffic flow (“Service Map”) in real-time. You not only see that a connection fails, but why (e.g., “Policy Denied”, “DNS Error”). This happens completely passively via eBPF, without overhead for the application.

4. Operational Models Compared: AWS VPC CNI vs. ayedo Managed Cilium

Here it is decided whether your network is scalable and transparent or if you fall into the typical traps of AWS architecture.

Scenario A: AWS VPC CNI (The IP Trap & Blind Flight)

The AWS VPC CNI plugin is the standard on EKS. It assigns each pod a real VPC IP address. This sounds good but leads to massive problems:

• IP Exhaustion: In small subnets, you quickly run out of IP addresses. Pods can no longer start (“Pending”) because the subnet is full. You need to configure complex “Secondary CIDRs” to solve this.
• Lack of Visibility: AWS VPC Flow Logs only show you metadata (Who with Whom). You don’t see HTTP error codes, DNS latencies, or Layer-7 traffic. You are flying blind.
• Limited Security: You rely on Security Groups, which are built for static VMs, not dynamic microservices.

Scenario B: Cilium with Managed Kubernetes by ayedo

In the ayedo App Catalog, Cilium is the standard component for CNI (Container Network Interface).

• Overlay Networking: Cilium can (optionally) use an overlay network (VXLAN). Pods receive internal IPs that do not consume precious AWS VPC IPs. The problem of IP exhaustion no longer exists.
• Hubble UI: The graphical interface for network analysis is integrated and pre-configured out-of-the-box.
• Transparent Encryption: With one click, ayedo activates WireGuard encryption. All traffic between nodes is transparently encrypted without the application having to manage certificates.
• Portable Policies: Your network rules (“NetworkPolicies”) are standard YAMLs. They work on AWS just as well as on Azure or on-prem.

Technical Comparison of Operational Models

FAQ: Cilium & Network Strategy

Is eBPF really faster or is it just hype?

It is measurably faster, especially under high load. Since eBPF minimizes context switching between user space and kernel space and avoids large iptables lists, latency decreases and throughput increases. For high-performance workloads (databases, AI, trading), eBPF is the gold standard today.

Does Cilium replace a Service Mesh like Istio?

Partially. Cilium offers many features with the “Cilium Service Mesh” (L7 LoadBalancing, Ingress, mTLS) that previously required a heavyweight Istio—but without the complex “sidecar container” per pod. For pure traffic management and observability, Cilium is often completely sufficient (“Sidecar-less Service Mesh”).

Does Cilium help with Compliance (PCI-DSS, GDPR)?

Yes. With Hubble, you can precisely demonstrate which service communicated with which other service (and who was blocked). This visual proof of network segmentation is often invaluable for audits, while AWS Flow Logs need to be laboriously evaluated.

Does WireGuard encryption work across cloud boundaries?

Yes. Cilium can be configured (e.g., in Cluster Mesh mode) to securely encrypt traffic between clusters—whether they are in different AWS regions or with different providers. This enables secure hybrid cloud scenarios without complex VPN gateways.

Conclusion

The network is the nervous system of the cluster. Those who rely on AWS’s standard CNI accept blind spots in security and operational risks due to IP scarcity. Cilium brings intelligence where it belongs: into the kernel, through eBPF. With the ayedo Managed Stack, companies gain access to this high technology—including observability through Hubble and encryption through WireGuard—without delving into the depths of kernel bytecode. The result is a high-performance, transparent, and portable network architecture.