If you’ve ever stared at kubectl get nodes waiting for a new node to appear and transition to Ready, you’ve probably wondered — what’s actually happening behind the scenes? This post traces the complete lifecycle of an EKS worker node, from the moment an EC2 instance is triggered to the point it starts running your pods. The Big Picture Before diving into details, here’s a high-level overview of what happens: ...
In this post, we want to understand how a DNS request in K8s pod gets resolved. Let’s create a mental model before we make a DNS request and see how packet moves through the cluster. Glossary Client Pod: This is going to be the pod which will make various kinds of DNS request. CoreDNS: This is the DNS server that we will use as DNS provider in our K8s cluster. Service: In K8s world, Service is a basically a ClusterIP backed by various Pods. Kube-Proxy: This component is responsible to configuring service routing on the Node. It configures the IPTable rules which translates the ServiceIP to PodIPs. Kubernetes DNS Architecture Before diving into the packet flow, let’s understand the basic DNS architecture in Kubernetes: ...