Add monitoring-ns kustomization manifest

Kustomize does not auto-create namespaces- this feature was
removed due to kubernetes-sigs/kustomize#514.
The monitoring-ns resource can be included in kustomizations that
also include other monitoring resources, such as prometheus and
grafana, to avoid boilerplate involved in creating the namespace
manually.

Signed-off-by: Ryan Drew <[email protected]>

README.md

@@ -164,6 +164,12 @@ Three dashboards are provided out-of-the-box in `kustomize/grafana/dashboards`,
 
 A dashboard provider is used to accomplish this. See the [grafana docs](https://grafana.com/docs/grafana/latest/administration/provisioning/#dashboards) for more information.
 
+### monitoring-ns
+
+Creates a namespace named 'monitoring'.
+Kustomize doesn't auto-create namespaces, so something needs to create the 'monitoring' ns for resources like prometheus and grafana (see above).
+By including this manifest, you won't have to manually create the namespace before a `kustomize build | kubectl apply -f -`.
+
 ### registry
 
 Deploys an in-cluster registry in the namespace `registry`, available through the service named `registry`.

kustomize/monitoring-ns/kustomization.yaml

@@ -0,0 +1,4 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+- namespace.yaml

kustomize/monitoring-ns/namespace.yaml

@@ -0,0 +1,4 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: monitoring