MX record with CRD source

You can create and manage MX records with the help of CRD source
and DNSEndpoint CRD. Currently, this feature is only supported by aws, azure, cloudflare, digitalocean and google providers.

In order to start managing MX records you need to set the --managed-record-types=MX flag.

external-dns --source crd --provider {aws|azure|google|digitalocean} --managed-record-types=A --managed-record-types=CNAME --managed-record-types=MX

Targets within the CRD need to be specified according to the RFC 1034 (section 3.6.1). Below is an example of
example.com DNS MX record which specifies two separate targets with distinct priorities.

apiVersion: externaldns.k8s.io/v1alpha1
kind: DNSEndpoint
metadata:
  name: examplemxrecord
spec:
  endpoints:
    - dnsName: example.com
      recordTTL: 180
      recordType: MX
      targets:
        - 10 mailhost1.example.com
        - 20 mailhost2.example.com