/gce_auto_discovery

CoreDNS plugin to automatically discover GCE instances and template DNS records

Primary LanguageGoApache License 2.0Apache-2.0

gce_auto_discovery

This is a coredns plugin to auto discover GCE instances and template dns records based on data about the instances

Name

gce_auto_discovery - enables serving templated dns records from gcp compute instances

Description

The gce_auto_discovery plugin is useful for convention over configuration when using host records, or transitioning from using the gcp internal DNS to a custom DNS solution.

Syntax

gce_auto_discovery  {
    template    <Go template string>
    project     <A gcp project>
    credentials [FILENAME]
    fallthrough [ZONES...]
}

  • TEMPLATE A go template string(including sprig functions) to use for templating DNS records for compute instances

  • PROJECT the project ID of the Google Cloud project.

  • credentials is used for reading the credential file from FILENAME (normally a .json file). This field is optional. If this field is not provided then authentication will be done automatically, e.g., through environmental variable GOOGLE_APPLICATION_CREDENTIALS. Please see Google Cloud's authentication method for more details.

  • fallthrough If zone matches and no record can be generated, pass request to the next plugin. If [ZONES...] is omitted, then fallthrough happens for all zones for which the plugin is authoritative. If specific zones are listed (for example in-addr.arpa and ip6.arpa), then only queries for those zones will be subject to fallthrough.

Examples

Enable clouddns with implicit GCP credentials and resolve CNAMEs via 10.0.0.1:

. {
    gce_auto_discovery {
        template "{{ .Name }}.{{ .Project }}.example.org."
    }
    forward . 10.0.0.1
}

Mimic googles internal DNS with an option to override the .Name property with a label on the compute instance

.internal {
    gce_auto_discovery {
        template "{{ .Labels.dns | default .Name }}.{{ .Zone }}.c.{{ .Project }}.internal."
    }
}