nomad-external-dns

Synchronize Nomad Services with external DNS providers.

Inspired by kubernetes-sigs/external-dns, nomad-external-dns makes Nomad Services discoverable via DNS servers. Nomad 1.3+ bundles support for native service discovery and nomad-external-dns helps to advertise the services inside this registry to external DNS providers.

Supported Providers

AWS Route 53
CloudFlare - Coming Soon!

How it Works

nomad-external-dns uses the concept of "Annotated Tags" to set properties for the DNS records. Here's an example of a service stanza inside a Nomad jobspec:

    service {
      provider = "nomad"
      name     = "redis-cache"
      tags = [
        "external-dns/hostname=redis.test.internal",
        "external-dns/ttl=30s",
      ]
      port = "db"
    }

At every app.update_interval frequency, list of all services across namespaces in the Nomad cluster are fetched.
For each service, external-dns prefix is used to determine properties like TTL, Hostname etc.
DNS record for this service is created with the registered DNS Provider. nomad-external-dns creates or updates an existing record automatically.

Deploy

NOTE: This is meant to run inside a Nomad cluster and should have proper ACL to query for services across multiple namespaces.

You can choose one of the various deployment options:

Binary

Grab the latest release from Releases.

To run:

$ ./nomad-external-dns.bin --config config.toml

Nomad

Refer to the jobspec for deploying in a Nomad cluster.

If you're deploying on AWS, consider referring to the IAM policy mentioned here

Configuration

Refer to config.sample.toml for a list of configurable values.

Environment Variables

All config variables can also be populated as env vairables by prefixing NOMAD_EXTERNAL_DNS_ and replacing . with __.

For eg: app.update_interval becomes NOMAD_EXTERNAL_DNS_app__update_interval.

For configuring Nomad API client, these environment variables can be set.

Contribution

Support for new providers can be added by registering more providers using libdns.
Feel free to report any bugs/feature requests.

mr-karan/nomad-external-dns