Add example for multibases

examples/README.md

@@ -36,3 +36,5 @@ go get github.com/kubernetes-sigs/kustomize
  * [container args](wordpress/README.md) - Injecting k8s runtime data into container arguments (e.g. to point wordpress to a SQL service).
  
  * [image tags](imageTags.md) - Updating image tags without applying a patch.
+
+ * [multibases](multibases/README.md) - Composing three variants (dev, staging, production) with a common base.

examples/multibases/README.md

@@ -0,0 +1,122 @@
+# Demo: multibases with a common base
+
+When managing application in different environment, many Kustomize users have seen this scenario. There is a base _Kustomization_ for this application. On top of this base, there are several variants such as dev, staging and production variants. In each of those variants, a different _namePrefix_ is applied. Users sometimes need to create another _kustomization_ compsing all three variants, applying the same _namePrefix_, _commonLables_ or _commonAnnotations_ and deploying them together with one `kubectl` command.
+
+Kustomize supports composing multiple variants like that in the same `kustomization.yaml`. This demo shows how this works with a pod object.
+
+Define a place to work:
+
+<!-- @makeWorkplace @test -->
+```
+DEMO_HOME=$(mktemp -d)
+```
+
+Define a common base:
+<!-- @makeBase @test -->
+```
+BASE=$DEMO_HOME/base
+mkdir $BASE
+
+cat <<EOF >$BASE/kustomization.yaml
+resources:
+- pod.yaml
+EOF
+
+cat <<EOF >$BASE/pod.yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: myapp-pod
+  labels:
+    app: myapp
+spec:
+  containers:
+  - name: nginx
+    image: nginx:1.7.9
+EOF
+```
+
+Define a dev variant overlaying base:
+<!-- @makeDev @test -->
+```
+DEV=$DEMO_HOME/dev
+mkdir $DEV
+
+cat <<EOF >$DEV/kustomization.yaml
+bases:
+- ./../base
+namePrefix: dev-
+EOF
+```
+
+Define a staging variant overlaying base:
+<!-- @makeStaging @test -->
+```
+STAG=$DEMO_HOME/staging
+mkdir $STAG
+
+cat <<EOF >$STAG/kustomization.yaml
+bases:
+- ./../base
+namePrefix: stag-
+EOF
+```
+
+Define a production variant overlaying base:
+<!-- @makeProd @test -->
+```
+PROD=$DEMO_HOME/production
+mkdir $PROD
+
+cat <<EOF >$PROD/kustomization.yaml
+bases:
+- ./../base
+namePrefix: prod-
+EOF
+```
+
+Then define a _Kustomization_ composing three variants together:
+<!-- @makeTopLayer @test -->
+```
+cat <<EOF >$DEMO_HOME/kustomization.yaml
+bases:
+- ./dev
+- ./staging
+- ./production
+
+namePrefix: cluster-a-
+EOF
+```
+
+Now the workspace has following directories
+> ```
+> .
+> ├── base
+> │   ├── kustomization.yaml
+> │   └── pod.yaml
+> ├── dev
+> │   └── kustomization.yaml
+> ├── kustomization.yaml
+> ├── production
+> │   └── kustomization.yaml
+> └── staging
+>     └── kustomization.yaml
+> ```
+
+Confirm that the `kustomize build` output contains three pod objects from dev, staing and production variants.
+
+<!-- @confirmVariants @test -->
+```
+test 1 == \
+  $(kustomize build $DEMO_HOME | grep cluster-a-dev-myapp-pod | wc -l); \
+  echo $?
+  
+test 1 == \
+  $(kustomize build $DEMO_HOME | grep cluster-a-stag-myapp-pod | wc -l); \
+  echo $?
+  
+test 1 == \
+  $(kustomize build $DEMO_HOME | grep cluster-a-prod-myapp-pod | wc -l); \
+  echo $?    
+```
+

examples/multibases/base/kustomization.yaml

@@ -0,0 +1,2 @@
+resources:
+- pod.yaml

examples/multibases/base/pod.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: myapp-pod
+  labels:
+    app: myapp
+spec:
+  containers:
+  - name: nginx
+    image: nginx:1.7.9

examples/multibases/dev/kustomization.yaml

@@ -0,0 +1,4 @@
+bases:
+- ./../base
+
+namePrefix: dev-

examples/multibases/kustomization.yaml

@@ -0,0 +1,6 @@
+bases:
+- ./dev
+- ./staging
+- ./production
+
+namePrefix: cluster-a-

examples/multibases/production/kustomization.yaml

@@ -0,0 +1,4 @@
+bases:
+- ./../base
+
+namePrefix: prod-

examples/multibases/staging/kustomization.yaml

@@ -0,0 +1,4 @@
+bases:
+- ./../base
+
+namePrefix: staging-