v1alpha3-compliant cluster API provideri implementor's guide

kubernetes-sigs · Dec 4, 2019 · 8505b27 · 8505b27
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diff --git a/docs/book/SUMMARY.md b/docs/book/SUMMARY.md
diff --git a/docs/book/src/SUMMARY.md b/docs/book/src/SUMMARY.md
@@ -19,7 +19,12 @@
     - [Provider Implementers](./providers/implementers.md)
         - [v1alpha1 to v1alpha2](./providers/v1alpha1-to-v1alpha2.md)
         - [Cluster Infrastructure](./providers/cluster-infrastructure.md)
-
+        - [Implementer's Guide](./providers/implementers-guide/overview.md)
+          - [Naming](./providers/implementers-guide/naming.md)
+          - [Create Repo and Generate CRDs](./providers/implementers-guide/generate_crds.md)
+          - [Create API](./providers/implementers-guide/create_api.md)
+          - [Controllers and Reconciliation](./providers/implementers-guide/controllers_and_reconciliation.md)
+          - [Building, Running, Testing](./providers/implementers-guide/building_running_and_testing.md)
 - [Reference](./reference/reference.md)
     - [Glossary](./reference/glossary.md)
     - [Provider List](./reference/providers.md)

diff --git a/docs/book/src/providers/implementers-guide/building_running_and_testing.md b/docs/book/src/providers/implementers-guide/building_running_and_testing.md
@@ -0,0 +1,132 @@
+# Building, Running, Testing
+
+## Docker Image Name
+
+The patch in `config/default/manager_image_patch.yaml` will be applied to the manager pod. 
+Right now there is a placeholder `IMAGE_URL`, which you will need to change to your actual image.
+
+### Development Images
+It's likely that you will want one location and tag for release development, and another during development.
+
+The approach most Cluster API projects is using [a `Makefile` that uses `sed` to replace the image URL][sed] on demand during development.
+
+[sed]: https://github.com/kubernetes-sigs/cluster-api/blob/e0fb83a839b2755b14fbefbe6f93db9a58c76952/Makefile#L201-L204
+
+## Deployment
+
+### cert-manager
+
+Cluster API uses [cert-manager] to manage the certificates it needs for its webhooks. 
+Before you apply Cluster API's yaml, you should [install `cert-manager`][cm-install]
+
+[cert-manager]: https://github.com/jetstack/cert-manager
+[cm-install]: https://docs.cert-manager.io/en/latest/getting-started/install/kubernetes.html
+
+```
+kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/<version>/cert-manager.yaml
+```
+
+### Cluster API
+
+Before you can deploy the infrastructure controller, you'll need to deploy Cluster API itself.
+
+You can [use a precompiled manifest][install], or clone [`cluster-api`][capi] and apply its manifests using `kustomize`.
+
+``` shell
+cd cluster-api
+kustomize build config/default | kubectl apply -f-
+```
+
+Check the status of the manager to make sure it's running properly 
+
+```shell
+$ kubectl describe -n capi-system pod | grep -A 5 Conditions
+Conditions:
+  Type              Status
+  Initialized       True 
+  Ready             True 
+  ContainersReady   True 
+  PodScheduled      True 
+```
+
+
+[install]: https://cluster-api.sigs.k8s.io/tasks/installation.html#install-cluster-api
+
+### Your provider
+
+Now you can apply your provider as well:
+
+```
+$ cd cluster-api-provider-mailgun
+$ kustomize build config/default | envsubst | kubectl apply -f-
+$ kubectl describe -n cluster-api-provider-mailgun-system pod | grep -A 5 Conditions 
+Conditions:
+  Type              Status
+  Initialized       True 
+  Ready             True 
+  ContainersReady   True 
+  PodScheduled      True 
+```
+
+### Tiltfile
+Cluster API development requires a lot of iteration, and the "build, tag, push, update deployment" workflow can be very tedious. 
+[Tilt](https://tilt.dev) makes this process much simpler by watching for updates, then automatically building and deploying them. 
+
+You can visit [some example repositories][capidev], but you can get started by writing out a yaml manifest and using the following [`Tiltfile`][tiltfile]
+`kustomize build config/default | envsubst > capm.yaml`
+
+[capidev]: https://github.com/chuckha/capi-dev
+[tiltfile]: https://docs.tilt.dev/tiltfile_concepts.html
+
+```starlark
+allow_k8s_contexts('kubernetes-admin@kind)
+
+k8s_yaml('capm.yaml')
+
+docker_build('<your docker username or repository url>/cluster-api-controller-mailgun-amd64', '.')
+```
+
+You can then use Tilt to watch the logs coming off your container
+
+
+## Your first Cluster
+
+Let's try our cluster out. We'll make some simple YAML:
+
+```yaml
+apiVersion: cluster.x-k8s.io/v1alpha2
+kind: Cluster
+metadata:
+  name: hello-mailgun
+spec:
+  clusterNetwork:
+    pods:
+      cidrBlocks: ["192.168.0.0/16"]
+  infrastructureRef:
+    apiVersion: infrastructure.cluster.x-k8s.io/v1alpha3
+    kind: MailgunCluster
+    name: hello-mailgun
+---
+apiVersion: infrastructure.cluster.x-k8s.io/v1alpha3
+kind: MailgunCluster
+metadata:
+  name: hello-mailgun
+spec:
+  priority: "ExtremelyUrgent"
+  request: "Please make me a cluster, with sugar on top?"
+  requester: "[email protected]"
+```
+
+We apply it as normal with `kubectl apply -f <filename>.yaml`.
+
+If all goes well, you should be getting an email to the address you configured when you set up your management cluster:
+
+![An email from mailgun urgently requesting a cluster](cluster-email.png)
+
+## Conclusion
+
+Obviously, this is only the first step. 
+We need to implement our Machine object too, and log events, handle updates, and many more things.
+
+Hopefully you feel empowered to go out and create your own provider now. 
+The world is your Kubernetes-based oyster!
diff --git a/docs/book/src/providers/implementers-guide/cluster-email.png b/docs/book/src/providers/implementers-guide/cluster-email.png
diff --git a/docs/book/src/providers/implementers-guide/configure.md b/docs/book/src/providers/implementers-guide/configure.md
@@ -0,0 +1,159 @@
+# Configure
+
+## YAML
+
+`kubebuilder` generates most of the YAML you'll need to deploy a container. 
+We just need to modify it to add our new secrets. 
+
+First, let's add our secret as a [patch] to the manager yaml.
+
+`config/default/manager_config.yaml`:
+
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: controller-manager
+  namespace: system
+spec:
+  template:
+    spec:
+      containers:
+      - name: manager
+        env: 
+        - name: MAILGUN_API_KEY
+          valueFrom:
+            secretKeyRef:
+              name: mailgun-secret
+              key: api_key
+        - name: MAILGUN_DOMAIN
+          valueFrom:
+            configMapKeyRef:
+              name: mailgun-config
+              key: mailgun_domain
+        - name: MAIL_RECIPIENT
+          valueFrom:
+            configMapKeyRef:
+              name: mailgun-config
+              key: mail_recipient
+```
+
+And then, we have to add that patch to [`config/default/kustomization.yaml`][kustomizeyaml]:
+
+```yaml
+patchesStrategicMerge
+- manager_image_patch.yaml
+# Protect the /metrics endpoint by putting it behind auth.
+# Only one of manager_auth_proxy_patch.yaml and
+# manager_prometheus_metrics_patch.yaml should be enabled.
+- manager_auth_proxy_patch.yaml
+# If you want your controller-manager to expose the /metrics
+# endpoint w/o any authn/z, uncomment the following line and
+# comment manager_auth_proxy_patch.yaml.
+# Only one of manager_auth_proxy_patch.yaml and
+# manager_prometheus_metrics_patch.yaml should be enabled.
+- manager_config.yaml
+```
+
+[kustomizeyaml]: https://github.com/kubernetes-sigs/kustomize/blob/master/docs/glossary.md#kustomization
+[patch]: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md
+
+## Our configuration
+
+There's many ways to manage configuration in production.
+The convention many Cluster-API projects use is enviroment variables.
+
+`config/manager/configuration.yaml`
+
+```yaml
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: mailgun-config
+  namespace: system
+type: Opaque
+stringData:
+  api_key: ${MAILGUN_API_KEY}
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: mailgun-config
+  namespace: system
+data:
+  mailgun_domain: ${MAILGUN_DOMAIN}
+  mail_recipient: ${MAILGUN_RECIPIENT}
+```
+
+And add this to `config/manager/kustomization.yaml`
+
+```yaml
+resources:
+- manager.yaml
+- credentials.yaml
+```
+
+You can now (hopefully) generate your yaml!
+
+```
+kustomize build config/default
+```
+
+## RBAC Role
+
+The default [RBAC role][role] contains permissions for accessing your cluster infrastructure CRDs, but not for accessing Cluster API resources. 
+You'll need to add these to `config/rbac/role.yaml`
+
+[role]: https://kubernetes.io/docs/reference/access-authn-authz/rbac/
+
+```diff
+diff --git a/config/rbac/role.yaml b/config/rbac/role.yaml
+index e9352ce..29008db 100644
+--- a/config/rbac/role.yaml
++++ b/config/rbac/role.yaml
+@@ -6,6 +6,24 @@ metadata:
+   creationTimestamp: null
+   name: manager-role
+ rules:
++- apiGroups:
++  - cluster.x-k8s.io
++  resources:
++  - clusters
++  - clusters/status
++  verbs:
++  - get
++  - list
++  - watch
++- apiGroups:
++  - cluster.x-k8s.io
++  resources:
++  - machines
++  - machines/status
++  verbs:
++  - get
++  - list
++  - watch
+ - apiGroups:
+   - infrastructure.cluster.x-k8s.io
+   resources:
+```
+
+## EnvSubst
+
+_A tool like [direnv](https://direnv.net/) can be used to help manage enviroment variables._
+
+
+`kustomize` does not handle replacing those `${VARIABLES}` with actual values. 
+For that, we use [`envsubst`][envsubst].
+
+You'll need to have those environment variables (`MAILGUN_API_KEY`, `MAILGUN_DOMAIN`, `MAILGUN_RECIPIENT`) in your environment when you generate the final yaml file.
+
+Then we call envsubst in line, like so:
+
+```
+kustomize build config/default | envsubst
+```
+
+[envsubst]: https://linux.die.net/man/1/envsubst
+