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code/kubernetes/kustomize/README.md

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+## wordpress with cdk
+
+<br>
+
+[Kustomize](https://kustomize.io/) is a tool that lets you create an entire Kubernetes application out of individual pieces — without touching the YAML for the individual components.
+
+Kustomize traverses a Kubernetes manifest to add, remove, or update configuration options without forking. Kustomize is available both as a standalone binary and as a native feature of kubectl.
+
+Kustomize enables you to do that by creating a file that ties everything together, or optionally includes “overrides” for individual parameters.
+
+In this example, you will learn how to use Kustomize to setup a Wordpress Kubernetes clusters. Please also check out [this article for a more deatailed explanation](https://medium.com/python-for-the-utopian/a-quick-introduction-to-kustomize-for-kubernetes-73490efa0966).
+
+<br>
+
+### Set Minukube
+
+For this demo, you can use a local Kubernetes cluster that can be provided by [minikube](https://github.com/kubernetes/minikube). Install minikube following [this](instructions).
+
+Start your cluster:
+
+```
+minikube start
+```
+
+<br>
+
+### Install Kustomize
+
+```
+brew install kustomize
+kustomize version
+```
+
+### Deploying Wordpress
+
+To run WordPress, it's necessary to connect WordPress with a MySQL database and access the service name of MySQL database from WordPress container.
+
+Set the base directory:
+
+```
+KUSTOM_HOME=$(pwd)
+BASE=$KUSTOM_HOME/base
+```
+
+Deploy Wordpress:
+
+```
+WORDPRESS_HOME=$BASE/wordpress
+cd $WORDPRESS_HOME
+kubectl apply -f $WORDPRESS_HOME
+```
+
+Deploy MySQL:
+
+```  
+MYSQL_HOME=$BASE/mysql
+cd $MYSQL_HOME
+kubectl apply -f $MYSQL_HOME
+```
+
+In each of these two directories, you should see three resources YAML files, and they are the elements of each individual deployment:
+
+- `deployment.yaml`
+- `kustomization.yaml`
+- `service.yaml`
+
+In the next step, we will use Kustomize to deploy everything by combining these files into a single file. But before we move on, let's clean up the individual deployments:
+
+```
+kubectl delete -f $WORDPRESS_HOME
+kubectl delete -f $MYSQL_HOME
+```
+
+The way Kustomize connects these two directories is by adding the following in their
+`kustomization.yaml` files:
+
+```
+commonLabels:
+  app: my-wordpress
+```
+
+Now we can use Kustomize to build the new YAML. The output from Kustomize is the concatenation of YAML documents for all the resources we specified, with the common labels added, which can be piped directly to `kubectl`:
+
+```
+kustomize build $BASE | kubectl apply -f -
+```
+
+Now, you can check that the services are up (you should see `mysql` and `wordpress`):
+
+```
+kubectl get services
+```
+
+<br>
+
+### Applying Overlays
+
+
+Overlays enable us to take the base YAML and selectively change pieces of it.  
+
+In this example, we’re going to create an overlay that includes a patch to change the Services to NodePort type services.
+
+The overlay should not be in the same directory as the base files, and in this case, we are using `$BASE/overlays/dev`.
+
+From the root directory, run:
+```
+OVERLAY_HOME=($pwd)/overlays
+DEV_HOME=$OVERLAY_HOME/dev
+cd $DEV_HOME
+```
+
+Now you can apply the overlay changes with:
+
+```
+kubectl apply -k $DEV_HOME
+```
+
+## Cleaning app
+
+
+To clean up the resources created from this exercise:
+
+```
+kubectl delete -f $BASE
+minikube stop
+```

code/kubernetes/kustomize/base/kustomization.yaml

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+commonLabels:
+  app: my-wordpress
+bases:
+- ./wordpress
+- ./mysql

code/kubernetes/kustomize/base/mysql/deployment.yaml

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+apiVersion: 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: {}

code/kubernetes/kustomize/base/mysql/kustomization.yaml

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+resources:
+- deployment.yaml
+- service.yaml
+- secret.yaml

code/kubernetes/kustomize/base/mysql/secret.yaml

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

code/kubernetes/kustomize/base/mysql/service.yaml

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

code/kubernetes/kustomize/base/wordpress/deployment.yaml

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+apiVersion: apps/v1beta2 
+kind: Deployment
+metadata:
+  name: wordpress
+  labels:
+    app: wordpress
+spec:
+  selector:
+    matchLabels:
+      app: wordpress
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: wordpress
+    spec:
+      containers:
+      - image: wordpress:4.8-apache
+        name: wordpress
+        ports:
+        - containerPort: 80
+          name: wordpress
+        volumeMounts:
+        - name: wordpress-persistent-storage
+          mountPath: /var/www/html
+      volumes:
+      - name: wordpress-persistent-storage
+        emptyDir: {}

code/kubernetes/kustomize/base/wordpress/kustomization.yaml

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+resources:
+- deployment.yaml
+- service.yaml

code/kubernetes/kustomize/base/wordpress/service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: wordpress
+  labels:
+    app: wordpress
+spec:
+  ports:
+    - port: 80
+  selector:
+    app: wordpress
+  type: LoadBalancer

code/kubernetes/kustomize/overlays/.gitkeep

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+

code/kubernetes/kustomize/overlays/dev/kustomization.yaml

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+bases:
+- ../../base
+patchesStrategicMerge:
+- localserv.yaml

code/kubernetes/kustomize/overlays/dev/localserv.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: wordpress
+spec:
+  type: NodePort
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: mysql
+spec:
+  type: NodePort