CoreDNS: DNS and Service Discovery for Kubernetes

CoreDNS is a DNS server created in Go, designed for flexibility across diverse environments. The project is open source under the Apache License Version 2 and maintains active development on GitHub, with community discussion centered on Slack’s #coredns channel.

Key Features

Plugin Architecture

The system uses a chaining approach where individual plugins handle specific DNS tasks, including “Kubernetes service discovery, Prometheus metrics or rewriting queries,” among others.

Design Philosophy

The developers prioritize simplicity and sensible defaults. Their Corefile configuration for coredns.io demonstrates this straightforward approach:

coredns.io {
  file coredns.io.signed {
    transfer to * 185.49.140.62
  }
  prometheus
  errors
  log
}

Service Discovery

Integration capabilities include the Kubernetes plugin for Kubernetes environments and the etcd plugin for direct etcd connectivity.

Performance and Customization

The platform emphasizes speed and efficiency while offering flexibility through its modular plugin system, allowing compilation with only necessary components.

Recognition

CoreDNS achieved graduated project status within the Cloud Native Computing Foundation (CNCF), making it a production-grade, enterprise-ready DNS solution.