Redis Powered DNS Server in GoLang

This is a DNS server that uses Redis as the backend. Redis records are stored according to the FQDN (with trailing dot) as the key, and a JSON payload as the value.

JSON Payload:

{
    "cnames": ["foo-12345.example.com."],
    "fqdn": "foo-12345.example.com.",
    "id": 27469,
    "ipv4_public_ips": ["104.0.0.1"],
    "ipv6_public_ips": [],
    "mbox": "admin.example.com."
    "mx_servers": [],
    "name_servers": ["ns1.example.com", "ns2.example.com"],
    "soa": "example.com"
    "ttl": 300,
}

• supply cnames or ipv4_public_ips, not both
• mbox admin.example.com # Don't use '@' in DNS email addresses
• wildcard records, eg. www.foo-12345.example.com. are supported. The Redis key for wildcards is *.foo-12345.example.com..

Usage:

./redis-dns-server \
    -redis-server-url redis://127.0.0.1:6379 \
    -port 5300

Port 53 is the standard port. Using a port less than 1024 will require root privileges.

Development

Building

General build steps:

Download from github and build using golang 1.11 Dependencies are automatically installed

$ go build
$ ./redis-dns-server --help

Using Vagrant

A simple Vagrantfile is provided to quickly spin up an Ubuntu 14.04 LTS box, that already has GoLang installed, as well as the latest version of Docker, and Docker Compose.

$ vagrant up
$ vagrant ssh

Inside Vagrant, the current working project directory will be accessible at /vagrant.

Using Docker and Docker Compose

Either from your local machine running Docker, or from within the Vagrant box:

$ cp -a docker-compose.env.example docker-compose.env
$ docker-compose up

To rebuild the image manually:

$ docker-compose build

Deployment

Docker

Reference the above Development section for using Docker Compose. Alternatively, Redis DNS Server can be deployed with Docker in the following fashion.

Building

$ make linux
$ docker build -t 'redis-dns-server:latest' .

Linking With a Redis Container

$ docker run -tid --name redis redis
$ docker run -itd \
    -e DOMAIN="example.com" \
    -e HOSTNAME="myhostname.example.com" \
    --link redis:db \
    -p 53:53 \
    redis-dns-server:latest

Linking With an External Redis Server

$ docker run -itd \
    -e DOMAIN="example.com" \
    -e HOSTNAME="myhostname.example.com" \
    -e REDIS_HOST="redis.example.com" \
    -p 53:53 \
    redis-dns-server:latest

Using an Environment File

You can load all ENV variables from an ENV file. An example ENV file can be found at docker-compose.env.example, and looks something like:

REDIS_HOST=redis.example.com
REDIS_PORT=6379
REDIS_DB=0
REDIS_USERNAME=myuser
REDIS_PASSWORD=mypassword
DOMAIN=example.com
DOMAIN_EMAIL=admin.example.com
HOSTNAME=myhostname.example.com

Using it:

$ docker run -itd \
    --env-file /path/to/myenv.file \
    -p 53:53 \
    redis-dns-server:latest

Inspiration:

• https://github.com/ConradIrwin/aws-name-server
• https://github.com/miekg/dns

TODO List: