ExternalDNS - Dreamhost Webhook

❤️ this project is a clone of external-dns-vultr-webhook with adaptations for Dreamhost using go-dreamhost project from @adamantal. It is in alpha and massively experimental, so please take care when you use it. It should not be used in production!

ExternalDNS is a Kubernetes add-on for automatically managing Domain Name System (DNS) records for Kubernetes services by using different DNS providers. By default, Kubernetes manages DNS records internally, but ExternalDNS takes this functionality a step further by delegating the management of DNS records to an external DNS provider such as this one. Therefore, the Dreamhost webhook allows to manage your Dreamhost domains inside your kubernetes cluster with ExternalDNS.

To use ExternalDNS with Dreamhost, you need your Dreamhost API token of the account managing your domains, which you can generate by visiting this page on the Dreamhost website.

For detailed technical instructions on how the Dreamhost webhook is deployed using the Bitnami Helm charts for ExternalDNS, see deployment instructions.

Kubernetes Deployment

The deployment can be performed in every way Kubernetes supports. The following example shows the deployment as a sidecar container in the ExternalDNS pod using the Bitnami Helm charts for ExternalDNS.

⚠️ This webhook requires at least ExternalDNS v0.14.0.

The webhook can be installed using either the Bitnami chart or the ExternalDNS one.

First, create the Dreamhost secret:

kubectl create secret generic dreamhost-credentials --from-literal=api-key='<EXAMPLE_PLEASE_REPLACE>' -n external-dns

Using the ExternalDNS helm chart

Skip this if you already have the ExternalDNS repository added:

helm repo add external-dns https://kubernetes-sigs.github.io/external-dns/

You can then create the helm values file, for example external-dns-dreamhost-values.yaml:

namespace: external-dns
policy: sync
provider:
  name: webhook
  webhook:
    image:
      repository: asymingt/external-dns-dreamhost-webhook
      tag: v0.1.2
    env:
      - name: DREAMHOST_API_KEY
        valueFrom:
          secretKeyRef:
            name: dreamhost-credentials
            key: api-key
    livenessProbe:
      httpGet:
        path: /health
        port: http-wh-metrics
      initialDelaySeconds: 10
      timeoutSeconds: 5
    readinessProbe:
      httpGet:
        path: /ready
        port: http-wh-metrics
      initialDelaySeconds: 10
      timeoutSeconds: 5
interval: 10m

And then:

# install external-dns with helm
helm install external-dns-dreamhost external-dns/external-dns -f external-dns-dreamhost-values.yaml --version 1.14.3 -n external-dns

Environment variables

The following environment variables are available:

Variable	Description	Notes
DREAMHOST_API_KEY	Dreamhost API token	Mandatory
DRY_RUN	If set, changes won't be applied	Default: false
WEBHOOK_HOST	Webhook hostname or IP address	Default: localhost
WEBHOOK_PORT	Webhook port	Default: 8888
HEALTH_HOST	Liveness and readiness hostname	Default: 0.0.0.0
HEALTH_PORT	Liveness and readiness port	Default: 8080
READ_TIMEOUT	Servers' read timeout in ms	Default: 60000
WRITE_TIMEOUT	Servers' write timeout in ms	Default: 60000

Additional environment variables for domain filtering:

Environment variable	Description
DOMAIN_FILTER	Filtered domains
EXCLUDE_DOMAIN_FILTER	Excluded domains
REGEXP_DOMAIN_FILTER	Regex for filtered domains
REGEXP_DOMAIN_FILTER_EXCLUSION	Regex for excluded domains

If the REGEXP_DOMAIN_FILTER is set, the following variables will be used to build the filter:

• REGEXP_DOMAIN_FILTER
• REGEXP_DOMAIN_FILTER_EXCLUSION

otherwise, the filter will be built using:

• DOMAIN_FILTER
• EXCLUDE_DOMAIN_FILTER

Tweaking the configuration

While tweaking the configuration, there are some points to take into consideration:

• if WEBHOOK_HOST and HEALTH_HOST are set to the same address/hostname or one of them is set to 0.0.0.0 remember to use different ports.

• if your records don't get deleted when applications are uninstalled, you might want to verify the policy in use for ExternalDNS: if it's upsert-only no deletion will occur. It must be set to sync for deletions to be processed. Please add the following to external-dns-dreamhost-values.yaml if you want this strategy:

  policy: sync

Development

The basic development tasks are provided by make. Run make help to see the available targets.