Skip to content

Latest commit

 

History

History
156 lines (111 loc) · 7.85 KB

README.md

File metadata and controls

156 lines (111 loc) · 7.85 KB
Raw

ExternalDNS Webhook Provider for Mikrotik

Important

While this software has reached version v1.0.0, it has not yet undergone extensive testing in large-scale, real-world environments. As such, it may still have bugs and may not yet be fully suitable for production use.

I encourage users to report any issues or suggest improvements, as this project remains under active development. Thank you for contributing!

ExternalDNS is a Kubernetes add-on for automatically managing DNS records for Kubernetes ingresses and services by using different DNS providers. This webhook provider allows you to automate DNS records from your Kubernetes clusters into your MikroTik router.

Supported DNS record types: A, AAAA, CNAME, MX, NS, SRV, TXT

For examples of creating DNS records either via CRDs or via Ingress/Service annotations, check out the example/ directory.

🎯 Requirements

  • ExternalDNS >= v0.15.0

Note

v0.15.0 of ExternalDNS added support for providerSpecific annotations in Ingress/Service objects for webhook providers.

While older versions of ExternalDNS may work, support for this feature will not be present.

  • Mikrotik RouterOS (tested on 7.16 stable)

Note

While other versions of RouterOS might work, they have not been officially tested. If you are using this webhook successfully with a different ROS version, feel free to post a comment in #141

Thus far, we know for sure 7.16 works and 7.12 does not.

🚫 Limitations

Multiple Targets

Currently, DNSEndpoints with multiple targets are not supported. No error will be thrown, but only one record will be created with the first target from the list.

This means that when creating a DNSEndpoint like this, only the first of the two targets will be taken into account (i.e. 192.192.192.192).

---
apiVersion: externaldns.k8s.io/v1alpha1
kind: DNSEndpoint
metadata:
  name: a-record
spec:
  endpoints:
    - dnsName: a.example.com
      recordTTL: 3605
      recordType: A
      targets:
        - 192.192.192.192
        - 193.193.193.193

The problem is that the External DNS controller will detect a drift on this and it will continuously attempt to update the DNS record, thus it will constantly send PUT requests to your RouterOS instance on every reconciliation loop.

Regexp Records

While the webhook can read records with a regexp defined, external-dns itself cannot manage them. This means that they either need to be excluded via domainFilters or excludeDomains so that external-dns will not try to assume ownership over them.

The problem is that from Mikrotiks perspective, a DNS record can either have a name or a regexp. They are mutually exclusive.

This is problematic because, even though we can create an Endpoint with no name, external-dns will try to create a TXT record to keep track of the ownership over said record. If the main record has no name, it errors out creating the TXT record too, since the TXT record name is based on the name of the main record.

See #166

Multiple provider-specific annotations

In the case of multiple external-dns instances, each with a different provider (for example this one and the cloudflare one), there are problems with passing in annotations for provider-specific configuration. Due to a bug in the upstream external-dns, all annotations will be passed as provider-configuration.

This will cause the webhook to complain that invalid provider-specific configuration entries have been passed and error out. While this check can be removed, it will cause external-dns to continuously detect a drift between the Endpoint and the DNS records in RouterOS, thus attempting a new reconcile at every loop. This is also not desired.

See #140 and kubernetes-sigs/external-dns#4951

⚙️ Configuration Options

MikroTik Configuration

Environment Variable Description Default Value
MIKROTIK_BASEURL URL at which the RouterOS API is available. (ex. https://192.168.88.1:443) N/A
MIKROTIK_USERNAME Username for the RouterOS API authentication. N/A
MIKROTIK_PASSWORD Password for the RouterOS API authentication. N/A
MIKROTIK_SKIP_TLS_VERIFY Whether to skip TLS verification (true or false). false
LOG_FORMAT The format in which logs will be printed. (text or json) json
LOG_LEVEL The verbosity at which logs are printed logs. (debug, info, warn or error) info

Webhook Server Configuration

Environment Variable Description Default Value
SERVER_HOST The host address where the server listens. localhost
SERVER_PORT The port where the server listens. 8888
SERVER_READ_TIMEOUT Duration the server waits before timing out on read operations. N/A
SERVER_WRITE_TIMEOUT Duration the server waits before timing out on write operations. N/A
DOMAIN_FILTER List of domains to include in the filter. Empty
EXCLUDE_DOMAIN_FILTER List of domains to exclude from filtering. Empty
REGEXP_DOMAIN_FILTER Regular expression for filtering domains. Empty
REGEXP_DOMAIN_FILTER_EXCLUSION Regular expression for excluding domains from the filter. Empty

🚀 Deployment

  1. Create a service account in RouterOS. This local user needs read and write access to manage static DNS.

  2. Create a Kubernetes namespace for your External DNS deployment

    ---
apiVersion: v1
kind: Namespace
metadata:
  name: external-dns

  3. Create a Kubernetes secret with the connection details for your RouterOS instance:

    ---
apiVersion: v1
kind: Secret
metadata:
  name: mikrotik-credentials
  namespace: external-dns
stringData:
  MIKROTIK_BASEURL: "https://192.168.88.1:443"
  MIKROTIK_USERNAME: "external-dns"
  MIKROTIK_PASSWORD: "external-dns"
  MIKROTIK_SKIP_TLS_VERIFY: "true"

  4. Add the External DNS helm repository and update your local cache

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

  5. Configure your helm values. Take a look at the example values.yaml

  6. Install the External DNS helm chart

    helm upgrade --install --namespace external-dns external-dns external-dns/external-dns -f values.yaml

Tip

By default, support for MX, NS and SRV records is disabled and needs to be enabled via the --managed-record-types argument. Make sure to set --managed-record-types=SRV if you want to enable SRV records, and so on.

⭐ Stargazers

Star History Chart

🤝 Gratitude and Thanks

Thanks to all the people who donate their time to the Home Operations Discord community.