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https://github.com/funkypenguin/geek-cookbook/
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Update external-dns to use template
Signed-off-by: David Young <davidy@funkypenguin.co.nz>
This commit is contained in:
David Young
@@ -1,3 +1,17 @@
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---
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title: Support CSI VolumeSnapshots with snapshot-controller
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description: Add CSI VolumeSnapshot support with snapshot support
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values_yaml_url: https://github.com/bitnami/charts/blob/master/bitnami/external-dns/values.yaml
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helm_chart_version: 5.1.x
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helm_chart_name: external-dns
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helm_chart_repo_name: bitnami
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helm_chart_repo_url: https://charts.bitnami.com/bitnami
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helmrelease_name: external-dns
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helmrelease_namespace: external-dns
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kustomization_name: external-dns
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slug: External DNS
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---
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# External DNS
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Kubernetes' internal DNS / service-discovery means that every service is resolvable within the cluster. You can create a Wordpress pod with a database URL pointing to "mysql", and trust that it'll find the service named "mysql" in the same namespace. (*Or "mysql.weirdothernamespace" if you prefer*)
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@@ -12,81 +26,14 @@ ExternalDNS is a controller for Kubernetes which watches the objects you create
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* [x] [Flux deployment process](/kubernetes/deployment/flux/) bootstrapped
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* [x] API credentials for a [supported DNS provider](https://github.com/kubernetes-sigs/external-dns)
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## Preparation
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{% include 'kubernetes-flux-namespace.md' %}
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{% include 'kubernetes-flux-helmrepository.md' %}
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{% include 'kubernetes-flux-kustomization.md' %}
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{% include 'kubernetes-flux-helmrelease.md' %}
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### Namespace
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#### Configure External DNS
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We need a namespace to deploy our HelmRelease and associated ConfigMaps into. Per the [flux design](/kubernetes/deployment/flux/), I create this example yaml in my flux repo:
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```yaml title="/bootstrap/namespaces/namespace-external-dns.yaml"
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apiVersion: v1
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kind: Namespace
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metadata:
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name: external-dns
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```
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### HelmRepository
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Next, we need to define a HelmRepository (*a repository of helm charts*), to which we'll refer when we create the HelmRelease. We only need to do this once per-repository. In this case, we're using the (*prolific*) [bitnami chart repository](https://github.com/bitnami/charts/tree/master/bitnami), so per the [flux design](/kubernetes/deployment/flux/), I create this example yaml in my flux repo:
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```yaml title="/bootstrap/helmrepositories/helmrepository-bitnami.yaml"
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apiVersion: source.toolkit.fluxcd.io/v1beta1
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kind: HelmRepository
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metadata:
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name: bitnami
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namespace: flux-system
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spec:
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interval: 15m
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url: https://charts.bitnami.com/bitnami
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```
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### Kustomization
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Now that the "global" elements of this deployment (*just the HelmRepository in this case*z*) have been defined, we do some "flux-ception", and go one layer deeper, adding another Kustomization, telling flux to deploy any YAMLs found in the repo at `/external-dns`. I create this example Kustomization in my flux repo:
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```yaml title="/bootstrap/kustomizations/kustomization-external-dns.yaml"
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apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
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kind: Kustomization
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metadata:
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name: external-dns
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namespace: flux-system
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spec:
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interval: 15m
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path: ./external-dns
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prune: true # remove any elements later removed from the above path
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timeout: 2m # if not set, this defaults to interval duration, which is 1h
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sourceRef:
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kind: GitRepository
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name: flux-system
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validation: server
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healthChecks:
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- apiVersion: apps/v1
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kind: Deployment
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name: external-dns
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namespace: external-dns
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```
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### ConfigMap
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Now we're into the external-dns-specific YAMLs. First, we create a ConfigMap, containing the entire contents of the helm chart's [values.yaml](https://github.com/bitnami/charts/blob/master/bitnami/external-dns/values.yaml). Paste the values into a `values.yaml` key as illustrated below, indented 4 spaces (*since they're "encapsulated" within the ConfigMap YAML*). I create this example yaml in my flux repo:
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```yaml title="/external-dns/configmap-external-dns-helm-chart-value-overrides.yaml"
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: null
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name: external-dns-helm-chart-value-overrides
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namespace: external-dns
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data:
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values.yaml: |-
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# <upstream values go here>
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```
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--8<-- "kubernetes-why-full-values-in-configmap.md"
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Then work your way through the values you pasted, and change any which are specific to your configuration.
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I recommend changing:
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I recommend changing at least:
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```yaml
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sources:
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@@ -113,10 +60,11 @@ To:
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### Secret
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As you work your way through `values.yaml`, you'll notice that it contains specific placholders for credentials for various DNS providers.
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As you work your way through `values.yaml`, you'll notice that it contains specific placeholders for credentials for various DNS providers.
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Take for example, this config for cloudflare:
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```yaml title="Example snippet of CloudFlare config from ConfigMap"
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```yaml title="Example snippet of CloudFlare config from upstream values.yaml"
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cloudflare:
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## @param cloudflare.apiToken When using the Cloudflare provider, `CF_API_TOKEN` to set (optional)
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##
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@@ -151,39 +99,7 @@ Thanks to [Sealed Secrets](/kubernetes/sealed-secrets/), we have a safe way of c
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And your sealed secret would end up in `external-dns/sealedsecret-cloudflare-api-token.yaml`.
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### HelmRelease
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Lastly, having set the scene above, we define the HelmRelease which will actually deploy the external-dns controller into the cluster, with the config we defined above. I save this in my flux repo as:
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```yaml title="/external-dns/helmrelease-external-dns.yaml"
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apiVersion: helm.toolkit.fluxcd.io/v2beta1
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kind: HelmRelease
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metadata:
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name: external-dns
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namespace: external-dns
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spec:
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chart:
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spec:
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chart: external-dns
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version: 4.x
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sourceRef:
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kind: HelmRepository
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name: bitnami
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namespace: flux-system
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interval: 15m
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timeout: 5m
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releaseName: external-dns
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valuesFrom:
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- kind: ConfigMap
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name: external-dns-helm-chart-value-overrides
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valuesKey: values.yaml # This is the default, but best to be explicit for clarity
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```
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--8<-- "kubernetes-why-not-config-in-helmrelease.md"
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## Serving
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Once you've committed your YAML files into your repo, you should soon see some pods appear in the `external-dns` namespace!
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{% include 'kubernetes-flux-check.md' %}
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### Using CRDs
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@@ -229,6 +145,15 @@ spec:
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If DNS entries **aren't** created as you expect, then the best approach is to check the external-dns logs, by running `kubectl logs -n external-dns -l app.kubernetes.io/name=external-dns`.
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## Summary
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What have we achieved? By simply creating another YAML in our flux repo alongside our app HelmReleases, we can record and create the necessary DNS entries, without fiddly manual intervetion!
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!!! summary "Summary"
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Created:
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* [X] DNS records are created automatically based on YAMLs (*or even just on services and ingresses!*)
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--8<-- "recipe-footer.md"
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[^1]: Why yes, I **have** accidentally caused outages / conflicts by "leaking" DNS entries automatically!
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