demoReorgToEaseTesting

demos/mySql/README.md

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+# Demo: MySql
+
+This example takes some off-the-shelf k8s resources
+designed for MySQL, and customizes them to suit a
+production scenario.
+
+In the production environment we want:
+
+- MySQL resource names to be prefixed by 'prod-'.
+- MySQL resources to have 'env: prod' labels.
+- MySQL to use persistent disk for storing data.
+
+First make a place to work:
+<!-- @makeDemoHome @test -->
+```
+DEMO_HOME=$(mktemp -d)
+```
+
+### Download resources
+
+To keep this document shorter, the base resources
+needed to run MySql on a k8s cluster are off in a
+supplemental data directory rather than declared here
+as HERE documents.
+
+Download them:
+
+<!-- @downloadResources @test -->
+```
+curl -s  -o "$DEMO_HOME/#1.yaml" "https://raw.githubusercontent.com\
+/kubernetes-sigs/kustomize\
+/master/demos/mySql\
+/{deployment,secret,service}.yaml"
+```
+
+### Initialize kustomization.yaml
+
+The `kustomize` program gets its instructions from
+a file called `kustomization.yaml`.
+
+Start this file:
+
+<!-- @kustomizeYaml @test -->
+```
+touch $DEMO_HOME/kustomization.yaml
+```
+
+### Add the resources
+
+<!-- @addResources @test -->
+```
+cd $DEMO_HOME
+
+kustomize edit add resource secret.yaml
+kustomize edit add resource service.yaml
+kustomize edit add resource deployment.yaml
+
+cat kustomization.yaml
+```
+
+`kustomization.yaml`'s resources section should contain:
+
+> ```
+> resources:
+> - secret.yaml
+> - service.yaml
+> - deployment.yaml
+> ```
+
+### Name Customization
+
+Arrange for the MySQL resources to begin with prefix
+_prod-_ (since they are meant for the _production_
+environment):
+
+<!-- @customizeLabel @test -->
+```
+cd $DEMO_HOME
+
+kustomize edit set nameprefix 'prod-'
+
+cat kustomization.yaml
+```
+
+`kustomization.yaml` should have updated value of namePrefix field:
+
+> ```
+> namePrefix: prod-
+> ```
+
+This `namePrefix` directive adds _prod-_ to all
+resource names.
+
+<!-- @genNamePrefixConfig @test -->
+```
+kustomize build $DEMO_HOME
+```
+
+The output should contain:
+
+> ```
+> apiVersion: v1
+> data:
+>   password: YWRtaW4=
+> kind: Secret
+> metadata:
+>   ....
+>   name: prod-mysql-pass-d2gtcm2t2k
+> ---
+> apiVersion: v1
+> kind: Service
+> metadata:
+>   ....
+>   name: prod-mysql
+> spec:
+>   ....
+> ---
+> apiVersion: apps/v1beta2
+> kind: Deployment
+> metadata:
+>   ....
+>   name: prod-mysql
+> spec:
+>   selector:
+>     ....
+> ```
+
+### Label Customization
+
+We want resources in production environment to have
+certain labels so that we can query them by label
+selector.
+
+`kustomize` does not have `edit set label` command to add
+a label, but one can always edit `kustomization.yaml` directly:
+
+<!-- @customizeLabels @test -->
+```
+sed -i 's/app: helloworld/app: prod/' \
+    $DEMO_HOME/kustomization.yaml
+```
+
+At this point, running `kustomize build` will
+generate MySQL configs with name-prefix 'prod-' and
+labels `env:prod`.
+
+### Storage customization
+
+Off the shelf MySQL uses `emptyDir` type volume, which
+gets wiped away if the MySQL Pod is recreated, and that
+is certainly not desirable for production
+environment. So we want to use Persistent Disk in
+production. kustomize lets you apply `patches` to the
+resources.
+
+<!-- @createPatchFile @test -->
+```
+cat <<'EOF' > $DEMO_HOME/persistent-disk.yaml
+apiVersion: apps/v1beta2 # for versions before 1.9.0 use apps/v1beta2
+kind: Deployment
+metadata:
+  name: mysql
+spec:
+  template:
+    spec:
+      volumes:
+      - name: mysql-persistent-storage
+        emptyDir: null
+        gcePersistentDisk:
+          pdName: mysql-persistent-storage
+EOF
+```
+
+Add the patch file to `kustomization.yaml`:
+
+<!-- @specifyPatch @test -->
+```
+cat <<'EOF' >> $DEMO_HOME/kustomization.yaml
+patches:
+- persistent-disk.yaml
+EOF
+```
+
+Lets break this down:
+
+- In the first step, we created a YAML file named
+  `persistent-disk.yaml` to patch the resource defined
+  in deployment.yaml
+
+- Then we added `persistent-disk.yaml` to list of
+  `patches` in `kustomization.yaml`. `kustomize build`
+  will apply this patch to the deployment resource with
+  the name `mysql` as defined in the patch.
+
+
+The output of the following command can now be applied
+to the cluster (i.e. piped to `kubectl apply`) to
+create the production environment.
+
+<!-- @finalInflation @test -->
+```
+kustomize build $DEMO_HOME  # | kubectl apply -f -
+```

demos/mySql/deployment.yaml

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+apiVersion: apps/v1beta2 # for versions before 1.9.0 use apps/v1beta2
+kind: Deployment
+metadata:
+  name: mysql
+  labels:
+    app: mysql
+spec:
+  selector:
+    matchLabels:
+      app: mysql
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: mysql
+    spec:
+      containers:
+      - image: mysql:5.6
+        name: mysql
+        env:
+        - name: MYSQL_ROOT_PASSWORD
+          valueFrom:
+            secretKeyRef:
+              name: mysql-pass
+              key: password
+        ports:
+        - containerPort: 3306
+          name: mysql
+        volumeMounts:
+        - name: mysql-persistent-storage
+          mountPath: /var/lib/mysql
+      volumes:
+      - name: mysql-persistent-storage
+        emptyDir: {}

demos/mySql/secret.yaml

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+apiVersion: v1
+kind: Secret
+metadata:
+  creationTimestamp: null
+  name: mysql-pass-d2gtcm2t2k
+type: Opaque
+data:
+  # Default password is "admin".
+  password: YWRtaW4=

demos/mySql/service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: mysql
+  labels:
+    app: mysql
+spec:
+  ports:
+    - port: 3306
+  selector:
+    app: mysql