Denominator is a portable Java library for manipulating DNS clouds. Denominator has pluggable back-ends, initially including AWS Route53, Neustar Ultra, DynECT, and a mock for testing. We also ship a command line version so it's easy for anyone to try it out. Denominator currently supports basic zone and record features, but will soon include GEO (aka Directional) support and advanced usage. See Netflix Tech Blog for an introduction.

For your convenience, the denominator cli is a single executable file. Under the hood, the cli uses airline to look and feel like dig or git.

While still incubating, the denominator cli download will be updated frequently. Once stable, we'll look into homebrew, debian, rpm packages. In the mean time, here's how to get it.

1. Download denominator
2. Place it on your $PATH. (ex. ~/bin)
3. Set it to be executable. (chmod 755 ~/bin/denominator)

Advanced usage, including ec2 hooks are covered in the readme. Here's a quick start for the impatient.

If you just want to fool around, you can use the mock provider.

$ denominator -p mock zone list
denominator.io.
$ denominator -p mock record -z denominator.io. list
denominator.io.                                    SOA   3600   ns1.denominator.io. admin.denominator.io. 1 3600 600 604800 60
denominator.io.                                    NS    86400  ns1.denominator.io.

Different providers need different credentials. First step is to run ./denominator providers to see how many -c args you need and what values they should have:

$ denominator providers
provider             credential type  credential arguments
mock                
dynect               password         customer username password
ultradns             password         username password
route53              accessKey        accessKey secretKey
route53              session          accessKey secretKey sessionToken

Now, you can list your zones or records.

$ denominator -p ultradns -c my_user -c my_password zone list
--snip--
netflix.com.
--snip--
$ denominator -p ultradns -c my_user -c my_password record --zone netflix.com. list
--snip--
email.netflix.com.                                 A     3600   69.53.237.168
--snip--

Denominator exposes a portable model implemented by pluggable Providers such as route53, ultradns, dynect, or mock. Under the covers, providers are Dagger modules. Except for the mock, all current providers bind to jclouds libraries. That said, denominator has no core dependencies outside guava and dagger, so developers are free to implement providers however they choose.

Denominator can be resolved as maven dependencies, or equivalent in lein, gradle, etc. Here are the coordinates, noting you only need to list the providers you use.

<dependencies>
  <dependency>
    <groupId>com.netflix.denominator</groupId>
    <artifactId>denominator-core</artifactId>
    <version>${denominator.version}</version>
  </dependency>
  <dependency>
    <groupId>com.netflix.denominator</groupId>
    <artifactId>denominator-dynect</artifactId>
    <version>${denominator.version}</version>
  </dependency>
  <dependency>
    <groupId>com.netflix.denominator</groupId>
    <artifactId>denominator-route53</artifactId>
    <version>${denominator.version}</version>
  </dependency>
  <dependency>
    <groupId>com.netflix.denominator</groupId>
    <artifactId>denominator-ultradns</artifactId>
    <version>${denominator.version}</version>
  </dependency>
</dependencies>

Creating a connection to a provider requires that you have access to two things: the name of the provider, and as necessary, credentials for it.

import static denominator.CredentialsConfiguration.credentials;
...
DNSApiManager manager = Denominator.create("ultradns", credentials(username, password)); // manager is closeable, so please close it!

The credentials are variable length, as certain providers require more that 2 parts. The above returns an instance of DNSApiManager where apis such as ZoneApis are found. Here's how to list zones:

for (Iterator<String> zone = manager.getApi().getZoneApi().list(); zone.hasNext();) {
    processZone(zone.next());
}

If you are running unit tests, or don't have a cloud account yet, you can use mock, and skip the credentials part.

DNSApiManager manager = Denominator.create("mock");

The Denominator model is based on the ResourceRecordSet concept. A ResourceRecordSet is simply a group of records who share the same name and type. For example all address (A) records for the name www.netflix.com. are aggregated into the same ResourceRecordSet. The values of each record in a set are type-specific. These data types are implemented as map-backed interfaces. This affords both the strong typing of java and extensibility and versatility of maps.

For example, the following are identical:

mxData.getPreference();
mxData.get("preference");

To build:

$ git clone [email protected]:Netflix/denominator.git
$ cd denominator/
$ ./gradlew clean test install

• For high-level updates, follow denominatorOSS on Twitter.
• For questions, please tag denominator in StackOverflow.
• For bugs and enhancements, please use Github Issues.
• For email discussions, please post to the user forum
• For discussions on design and internals, please join #jclouds on irc freenode or post to the dev forum

Copyright 2013 Netflix, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.