CoreDNS

Introduction

CoreDNS is a flexible, plugin-based DNS server written in Go and the default Kubernetes cluster DNS since version 1.13. It chains plugins (cache, forward, kubernetes, prometheus, etc.) into a request-handling pipeline, allowing operators to compose exactly the DNS behavior they need for service discovery, split-horizon DNS, and authoritative zone serving. CoreDNS is a CNCF graduated project.

How to Install

Starting via Binary

Quick Start

# get and run from source
wget https://github.com/coredns/coredns/releases/download/v1.10.1/coredns_1.10.1_linux_amd64.tgz
tar xf coredns_1.10.1_linux_amd64.tgz
install -m 0755 coredns /usr/local/bin
coredns -conf /opt/coredns/coredns.conf 
# OR
git clone https://github.com/coredns/coredns
cd coredns && make
install -m 0755 coredns /usr/local/bin
coredns -conf /opt/coredns/coredns.conf -dns.port=1053

Config and Boot

Config

# create config
cat > /opt/coredns/coredns.conf << "EOF"
example.org:1053 {
    file /var/lib/coredns/example.org.signed
    transfer {
        to * 2001:500:8f::53
    }
    errors
    log
}

. {
    any
    forward . 8.8.8.8:53
    errors
    log
}
EOF

Boot(systemd)

cat > /etc/systemd/system/coredns.service << "EOF"
...
EOF

systemctl daemon-reload
systemctl start coredns.service
systemctl enable coredns.service

Starting via Docker

Run on Docker

# https://hub.docker.com/r/coredns/coredns/tags

Starting via Kubernetes

Deploy by Kubernetes Manifest

#

Deploy by Helm

# Add and update repo
helm repo add coredns https://coredns.github.io/helm
helm repo update

# Get charts package
helm pull coredns/coredns --untar
cd coredns

# Configure and run
vim values.yaml
...

helm -n kube-system install coredns .

Reference:

1. Official Website
2. Repository