dnscontrol

DNSControl

DNSControl is a system for maintaining DNS zones. It has two parts: a domain specific language (DSL) for describing DNS zones plus software that processes the DSL and pushes the resulting zones to DNS providers such as Route53, CloudFlare, and Gandi. It can talk to Microsoft ActiveDirectory and it generates the most beautiful BIND zone files ever. It run anywhere Go runs (Linux, macOS, Windows).

At Stack Overflow, we use this system to manage hundreds of domains and subdomains across multiple registrars and DNS providers.

You can think of it as a DNS compiler. The configuration files are written in a DSL that looks a lot like JavaScript. It is compiled to an intermediate representation (IR). Compiler back-ends use the IR to update your DNS zones on services such as Route53, CloudFlare, and Gandi, or systems such as BIND and ActiveDirectory.

An Example

dnsconfig.js:

// define our registrar and providers
var namecom = NewRegistrar("name.com", "NAMEDOTCOM");
var r53 = NewDnsProvider("r53", "ROUTE53")

D("example.com", namecom, DnsProvider(r53),
  A("@", "1.2.3.4"),
  CNAME("www","@"),
  MX("@",5,"mail.myserver.com."),
  A("test", "5.6.7.8")
)

Running dnscontrol preview will talk to the providers (here name.com as registrar and route 53 as the dns host), and determine what changes need to be made.

Running dnscontrol push will make those changes with the provider and my dns records will be correclty updated.

Benefits

• Editing zone files is error-prone. Clicking buttons on a web page is irreproducible.
• Switching DNS providers becomes a no-brainer. The DNSControl language is vendor-agnostic. If you use it to maintain your DNS zone records, you can switch between DNS providers easily. In fact, DNSControl will upload your DNS records to multiple providers, which means you can test one while switching to another. We've switched providers 3 times in three years and we've never lost a DNS record.
• Adopt CI/CD principles to DNS! At StackOverflow we maintain our DNSControl configurations in Git and use our CI system to roll out changes. Keeping DNS information in a VCS means we have full history. Using CI enables us to include unit-tests and system-tests. Remember when you forgot to include a "." at the end of an MX record? We haven't had that problem since we included a test to make sure Tom doesn't make that mistake... again.
• Variables save time! Assign an IP address to a constant and use the variable name throughout the file. Need to change the IP address globally? Just change the variable and "recompile."
• Macros! Define your SPF records, MX records, or other repeated data once and re-use them for all domains.
• Control CloudFlare from a single location. Enable/disable Cloudflare proxying (the "orange cloud" button) directly from your DNSControl files.
• Keep similar domains in sync with transforms and other features. If one domain is supposed to be the same
• It is extendable! All the DNS providers are written as plugins. Writing new plugins is very easy.

Installation

go get github.com/StackExchange/dnsontrol

or get prebuilt binaries from our github page.