[improvement] [test] [docs] add dns webook and flavor docs (#406)

* add dns webook and flavor docs
linode · Jul 10, 2024 · 598c935 · 598c935
1 parent 51681b7
commit 598c935
Show file tree

Hide file tree

Showing 3 changed files with 130 additions and 0 deletions.
diff --git a/api/v1alpha2/linodecluster_webhook.go b/api/v1alpha2/linodecluster_webhook.go
@@ -97,6 +97,21 @@ func (r *LinodeCluster) validateLinodeClusterSpec(ctx context.Context, client Li
 		errs = append(errs, err)
 	}
 
+	if r.Spec.Network.LoadBalancerType == "dns" {
+		if r.Spec.Network.DNSRootDomain == "" {
+			errs = append(errs, &field.Error{
+				Field: "dnsRootDomain needs to be set when LoadBalancer Type is DNS",
+				Type:  field.ErrorTypeRequired,
+			})
+		}
+		if r.Spec.Network.DNSUniqueIdentifier == "" {
+			errs = append(errs, &field.Error{
+				Field: "dnsUniqueIdentifier needs to be set when LoadBalancer Type is DNS",
+				Type:  field.ErrorTypeRequired,
+			})
+		}
+	}
+
 	if len(errs) == 0 {
 		return nil
 	}

diff --git a/api/v1alpha2/linodecluster_webhook_test.go b/api/v1alpha2/linodecluster_webhook_test.go
@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"go.uber.org/mock/gomock"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/utils/ptr"
@@ -110,3 +111,74 @@ func TestValidateCreate(t *testing.T) {
 		),
 	)
 }
+
+func TestValidateDNSLinodeCluster(t *testing.T) {
+	t.Parallel()
+
+	var (
+		validCluster = LinodeCluster{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "example",
+				Namespace: "example",
+			},
+			Spec: LinodeClusterSpec{
+				Region: "us-ord",
+				Network: NetworkSpec{
+					LoadBalancerType:    "dns",
+					DNSRootDomain:       "test.net",
+					DNSUniqueIdentifier: "abc123",
+				},
+			},
+		}
+		noRootDomainCluster = LinodeCluster{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "example",
+				Namespace: "example",
+			},
+			Spec: LinodeClusterSpec{
+				Region: "us-ord",
+				Network: NetworkSpec{
+					LoadBalancerType:    "dns",
+					DNSRootDomain:       "",
+					DNSUniqueIdentifier: "abc123",
+				},
+			},
+		}
+		noUniqueIDCluster = LinodeCluster{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "example",
+				Namespace: "example",
+			},
+			Spec: LinodeClusterSpec{
+				Region: "us-ord",
+				Network: NetworkSpec{
+					LoadBalancerType:    "dns",
+					DNSRootDomain:       "test.net",
+					DNSUniqueIdentifier: "",
+				},
+			},
+		}
+	)
+
+	NewSuite(t, mock.MockLinodeClient{}).Run(
+		OneOf(
+			Path(
+				Call("valid", func(ctx context.Context, mck Mock) {
+					mck.LinodeClient.EXPECT().GetRegion(gomock.Any(), gomock.Any()).Return(nil, nil).AnyTimes()
+				}),
+				Result("success", func(ctx context.Context, mck Mock) {
+					assert.NoError(t, validCluster.validateLinodeCluster(ctx, mck.LinodeClient))
+				}),
+			),
+		),
+		OneOf(
+			Path(Call("no domain and unique id set", func(ctx context.Context, mck Mock) {
+				mck.LinodeClient.EXPECT().GetRegion(gomock.Any(), gomock.Any()).Return(nil, nil).AnyTimes()
+			})),
+		),
+		Result("error", func(ctx context.Context, mck Mock) {
+			require.ErrorContains(t, noRootDomainCluster.validateLinodeCluster(ctx, mck.LinodeClient), "dnsRootDomain")
+			require.ErrorContains(t, noUniqueIDCluster.validateLinodeCluster(ctx, mck.LinodeClient), "dnsUniqueIdentifier")
+		}),
+	)
+}
diff --git a/docs/src/topics/flavors/dns-loadbalancing.md b/docs/src/topics/flavors/dns-loadbalancing.md
@@ -0,0 +1,43 @@
+# DNS based apiserver Load Balancing
+
+This flavor configures DNS records that resolve to the public (ipv4 and/or IPv6) IPs of the control plane nodes where the apiserver pods are running. No NodeBalancer will be created.
+This needs the following to be set in the `LinodeCluster` spec under `network`
+```bash
+kind: LinodeCluster
+spec:
+    network:
+        loadBalancerType: dns
+        dnsRootDomain: test.net
+        dnsUniqueIdentifier: abc123
+```
+Along with this, the `test.net` domain needs to be registered and also be pre-configured as a [domain on Linode CM](https://cloud.linode.com/domains).
+Using the `LINODE_DNS_TOKEN` env var, you can pass the [API token of a different account](https://cloud.linode.com/profile/tokens) if the Domain has been created in another acount under Linode CM
+
+With these changes, the controlPlaneEndpoint is set to `<domain-name>-<uniqueid>.<root-domain>`. This will set as the server in the KUBECONFIG as well.
+The controller will create A/AAAA and TXT records under [the Domains tab in the Linode Cloud Manager.](https://cloud.linode.com/domains)
+
+
+## Specification
+| Supported Control Plane | CNI    | Default OS   | Installs ClusterClass | IPv4 | IPv6 |
+|-------------------------|--------|--------------|-----------------------|------|------|
+| kubeadm                 | Cilium | Ubuntu 22.04 | No                    | Yes  | Yes  |
+
+## Prerequisites
+[Quickstart](../getting-started.md) completed
+
+## Usage
+1. Generate cluster yaml
+    ```bash
+    clusterctl generate cluster test-cluster \
+        --kubernetes-version v1.29.1 \
+        --infrastructure linode-linode \
+        --control-plane-machine-count 3 --worker-machine-count 3 \
+        --flavor <controlplane>-dns-loadbalancing > test-cluster.yaml
+    ```
+2. Apply cluster yaml
+    ```bash
+    kubectl apply -f test-cluster.yaml
+    ```
+
+## Check
+You should in a few moments see the records created and running a nslookup against the server endpoint should return a multianswer dns record