cilium

We all know the benefits of using managed Kubernetes services like GKE, EKS, AKS, etc. Given the complexity of managing the cluster infrastructure and its core components (control plane, auto-scaling, monitoring, networking, storage, etc.), using a managed Kubernetes service is generally the first choice when running workloads in production.

However, in some situations, provisioning and managing the Kubernetes cluster from scratch might be necessary. Specific product features, security & compliance, costs, vendor independency, etc. are some factors that usually justify the decision of running Kubernetes by yourself. Of course, many challenges come with managing a Kubernetes cluster and the discussion around which route - self-managed vs. managed - to take is far from simple. I want to keep this discussion out of the scope of this tutorial since it would require special attention.

Currently, the tool of choice when considering provisioning and managing a Kubernetes cluster is Cluster API. From the docs:

Cluster API is a Kubernetes sub-project focused on providing declarative APIs and tooling to simplify provisioning, upgrading, and operating multiple Kubernetes clusters.

[…] The supporting infrastructure, like virtual machines, networks, load balancers, and VPCs, as well as the Kubernetes cluster configuration are all defined in the same way that application developers operate deploying and managing their workloads. This enables consistent and repeatable cluster deployments across a wide variety of infrastructure environments.

In this tutorial, we will deploy Cilium to an Amazon EKS cluster and limit traffic to Pods using Kubernetes Network Policies.

Network Policies are not available in Kubernetes out-of-the-box. To leverage Network Policies, you must use a network plugin that implements such a feature - here is where Cilium comes into play.

It’s worth noting that while this is the scope of this tutorial, Cilium is not limited to Network Policies and not even limited to Kubernetes. Check the Introduction to Cilium to learn more about it and the Kubernetes Integration doc about how Cilium works with Kubernetes.

In this tutorial, we are going to play with the Google Kubernetes Engine Dataplane V2 and check how we can use it along with Kubernetes Network Policies to limit traffic to Pods and to obtain real-time visibility on cluster network activity.

Dataplane V2 is a recent feature in GKE, with GA starting on version 1.20.6-gke.700 as of May 10, 2021. It uses Cilium to process network packets in-kernel using Kubernetes-specific metadata without relying on the kube-proxy and iptables for service routing, resulting in performance improvements. Dataplane V2 brings some exciting features for cluster operations and security, such as:

• Built-in Network Policies enforcement without the need of Calico and;
• Real-time visibility, enabling cluster networking troubleshooting, auditing, and alerting.