DNS Operator

The DNS Operator is a kubernetes based controller responsible for reconciling DNS Record custom resources. It interfaces with cloud DNS providers such as AWS and Google to bring the DNS zone into the state declared in these CRDs. One of the key use cases the DNS operator solves, is allowing complex DNS routing strategies such as Geo and Weighted to be expressed allowing you to leverage DNS as the first layer of traffic management. In order to make these strategies valuable, it also works across multiple clusters allowing you to use a shared domain name balance traffic based on your requirements.

Getting Started

Pre Setup

Add DNS provider configuration

NOTE: You can optionally skip this step but at least one DNS Provider Secret will need to be configured with valid credentials to use the DNS Operator.

AWS Provider (Route53)

make local-setup-aws-clean local-setup-aws-generate AWS_ACCESS_KEY_ID=<My AWS ACCESS KEY> AWS_SECRET_ACCESS_KEY=<My AWS Secret Access Key>

More details about the AWS provider can be found here

GCP Provider

make local-setup-gcp-clean local-setup-gcp-generate GCP_GOOGLE_CREDENTIALS='<My GCP Credentials.json>' GCP_PROJECT_ID=<My GCP PROJECT ID>

More details about the GCP provider can be found here

AZURE Provider

make local-setup-azure-clean local-setup-azure-generate KUADRANT_AZURE_CREDENTIALS='<My Azure Credentials.json>'

Info on generating service principal credentials here

Get your resource group ID like so:

az group show --resource-group <resource group name> | jq ".id" -r

Also give traffic manager contributor role:

az role assignment create --role "Traffic Manager Contributor" --assignee $EXTERNALDNS_SP_APP_ID --scope <RESOURCE_GROUP_ID>

Getting the zone ID can be achieved using the below command:

az network dns zone show --name <my domain name> --resource-group <my resource group> --query "{id:id,domain:name}"

Running controller locally (default)

1. Create local environment(creates kind cluster)

   make local-setup

2. Run your controller (this will run in the foreground, so switch to a new terminal if you want to leave it running):

make run

Running controller on the cluster

1. Create local environment(creates kind cluster)

   make local-setup DEPLOY=true

2. Verify controller deployment

   kubectl logs -f deployments/dns-operator-controller-manager -n dns-operator-system

Running controller on existing cluster

You’ll need a Kubernetes cluster to run against. You can use KIND to get a local cluster for testing, or run against a remote cluster. Note: Your controller will automatically use the current context in your kubeconfig file (i.e. whatever cluster kubectl cluster-info shows).

1. Apply Operator manifests

   kustomize build config/default | kubectl apply -f -

2. Verify controller deployment

   kubectl logs -f deployments/dns-operator-controller-manager -n dns-operator-system

Development

E2E Test Suite

The e2e test suite can be executed against any cluster running the DNS Operator with configuration added for any supported provider.

make test-e2e TEST_DNS_ZONE_DOMAIN_NAME=<My domain name> TEST_DNS_PROVIDER_SECRET_NAME=<My provider secret name> TEST_DNS_NAMESPACES=<My test namespace(s)>

Modifying the API definitions

If you are editing the API definitions, generate the manifests such as CRs or CRDs using:

make manifests

NOTE: Run make --help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

Logging

Logs are following the general guidelines:

• logger.Info() describe a high-level state of the resource such as creation, deletion and which reconciliation path was taken.
• logger.Error() describe only those errors that are not returned in the result of the reconciliation. If error is occurred there should be only one error message.
• logger.V(1).Info() debug level logs to give information about every change or event caused by the resource as well as every update of the resource.

The --zap-devel argument will enable debug level logs for the output. Otherwise, all V() logs are ignored.

Common metadata

Not exhaustive list of metadata for DNSRecord controller:

• level - logging level. Values are: info,debug or error
• ts - timestamp
• logger - logger name
• msg
• controller and controllerKind - controller name, and it's kind respectively to output the log
• DNSRecord - name and namespace of the DNS Record CR that is being reconciled
• reconcileID
• ownerID - ID the of owner of the DNS Record
• txtPrefix/txtSuffix - prefix and suffix of the TXT record in provider.
• zoneEndpoints - endpoints that exist in the provider
• specEdnoinds - endpoints defined in the spec
• statusEndpoints - endpoints that were processed previously

Note that not all the metadata values are present at each of the logs statements.

Examples

To query logs locally you can use jq. For example: Retrieve logs by

kubectl get deployments -l app.kubernetes.io/part-of=dns-operator -A

NAMESPACE             NAME                              READY 
dns-operator-system   dns-operator-controller-manager   1/1   

And query them. For example:

kubectl logs -l control-plane=dns-operator-controller-manager -n dns-operator-system --tail -1 | sed '/^{/!d' | jq 'select(.controller=="dnsrecord" and .level=="info")'

or

kubectl logs -l control-plane=dns-operator-controller-manager -n dns-operator-system --tail -1 | sed '/^{/!d' | jq 'select(.controller=="dnsrecord" and .DNSRecord.name=="test" and .reconcileID=="2be16b6d-b90f-430e-9996-8b5ec4855d53")' | jq '.level, .msg, .zoneEndpoints, .specEndpoints, .statusEndpoints '

You could use selector in the jq with and/not/or to restrict.

License

Copyright 2024.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.