This article explains the fundamentals of DNS, its role as an application‑layer protocol, and how Kubernetes generates and manages each pod's /etc/resolv.conf through kubelet, covering nameserver, search, ndots options, dnsPolicy choices, and custom dnsConfig examples.
This article explains how CoreDNS runs on a Caddy‑based HTTP/2 server in Kubernetes, how kubelet injects the cluster DNS IP into each container’s /etc/resolv.conf, and how different dnsPolicy settings (Default, ClusterFirst, ClusterFirstWithHostNet, None) affect the resolv.conf configuration, including key options and examples.
An agent service running in a Kubernetes pod appeared healthy but failed to receive heartbeats due to DNS resolution errors caused by an unintended 'HOST' search domain, leading to incorrect IP resolution; the article details the investigation, explains Kubernetes DNS mechanics, and shows how adjusting ndots or using fully qualified names resolves the issue.
A Kubernetes pod appeared healthy but failed to receive heartbeats because its DNS search domain included a top‑level "HOST" entry, causing incorrect name resolution, and the article explains the root cause, analysis, and practical fixes such as using fully qualified names or adjusting ndots and dnsPolicy.
