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[improvement] [test] [docs] add dns webook and flavor docs (#406)
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* add dns webook and flavor docs
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amold1 authored Jul 10, 2024
1 parent 51681b7 commit 598c935
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15 changes: 15 additions & 0 deletions api/v1alpha2/linodecluster_webhook.go
Original file line number Diff line number Diff line change
Expand Up @@ -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
}
Expand Down
72 changes: 72 additions & 0 deletions api/v1alpha2/linodecluster_webhook_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down Expand Up @@ -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")
}),
)
}
43 changes: 43 additions & 0 deletions docs/src/topics/flavors/dns-loadbalancing.md
Original file line number Diff line number Diff line change
@@ -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

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