Address Issue #3827: break out Configuring Redis using a ConfigMap tutorial (#3829)

* Address Issue #3827: break out Configuring Redis using a ConfigMap tutorial

* format tweaks

docs/tutorials/configuration/configure-redis-using-configmap.md

@@ -0,0 +1,128 @@
+---
+assignees:
+- eparis
+- pmorie
+title: Configuring Redis using a ConfigMap
+---
+
+{% capture overview %}
+
+This page provides a real world example of how to configure Redis using a ConfigMap and builds upon the [Using ConfigMap Data in Pods](/docs/tasks/configure-pod-container/configure-pod-configmap/) and [Configure Containers Using a ConfigMap](/docs/tasks/configure-pod-container/configmap/) tasks. 
+
+{% endcapture %}
+
+{% capture objectives %}
+
+* Create a ConfigMap.
+* Create a pod specification using the ConfigMap.
+* Create the pod.
+* Verify that the configuration was correctly applied.
+
+{% endcapture %}
+
+{% capture prerequisites %}
+
+* {% include task-tutorial-prereqs.md %}
+* Understand [Using ConfigMap Data in Pods](/docs/tasks/configure-pod-container/configure-pod-configmap/).
+* Understand [Configure Containers Using a ConfigMap](/docs/tasks/configure-pod-container/configmap/).
+
+{% endcapture %}
+
+{% capture lessoncontent %}
+
+
+## Real World Example: Configuring Redis using a ConfigMap
+
+You can follow the steps below to configure a Redis cache using data stored in a ConfigMap.
+
+1. Create a ConfigMap from the `docs/user-guide/configmap/redis/redis-config` file:
+
+   ```shell
+   kubectl create configmap example-redis-config --from-file=docs/user-guide/configmap/redis/redis-config
+
+   kubectl get configmap example-redis-config -o yaml
+   ```
+
+   ```yaml
+   apiVersion: v1
+   data:
+     redis-config: |
+       maxmemory 2mb
+       maxmemory-policy allkeys-lru
+   kind: ConfigMap
+   metadata:
+     creationTimestamp: 2016-03-30T18:14:41Z
+     name: example-redis-config
+     namespace: default
+     resourceVersion: "24686"
+     selfLink: /api/v1/namespaces/default/configmaps/example-redis-config
+     uid: 460a2b6e-f6a3-11e5-8ae5-42010af00002
+   ```
+
+1. Create a pod specification that uses the config data stored in the ConfigMap:
+
+   ```yaml
+   apiVersion: v1
+   kind: Pod
+   metadata:
+     name: redis
+   spec:
+     containers:
+     - name: redis
+       image: kubernetes/redis:v1
+       env:
+       - name: MASTER
+         value: "true"
+       ports:
+       - containerPort: 6379
+       resources:
+         limits:
+           cpu: "0.1"
+       volumeMounts:
+       - mountPath: /redis-master-data
+         name: data
+       - mountPath: /redis-master
+         name: config
+     volumes:
+       - name: data
+         emptyDir: {}
+       - name: config
+         configMap:
+           name: example-redis-config
+           items:
+           - key: redis-config
+             path: redis.conf
+   ```
+1. Create the pod:
+
+   ```shell
+   kubectl create -f docs/user-guide/configmap/redis/redis-pod.yaml
+   ```
+
+   In the example, the config volume is mounted at `/redis-master`.
+   It uses `path` to add the `redis-config` key to a file named `redis.conf`.
+   The file path for the redis config, therefore, is `/redis-master/redis.conf`.
+   This is where the image will look for the config file for the redis master.
+
+1. Use `kubectl exec` to enter the pod and run the `redis-cli` tool to verify that the configuration was correctly applied:
+
+   ```shell
+   kubectl exec -it redis redis-cli
+   127.0.0.1:6379> CONFIG GET maxmemory
+   1) "maxmemory"
+   2) "2097152"
+   127.0.0.1:6379> CONFIG GET maxmemory-policy
+   1) "maxmemory-policy"
+   2) "allkeys-lru"
+   ```
+
+{% endcapture %}
+
+{% capture whatsnext %}
+
+* Learn more about [ConfigMaps](/docs/tasks/configure-pod-container/configmap/).
+* See [Using ConfigMap Data in Pods](/docs/tasks/configure-pod-container/configure-pod-configmap).
+
+{% endcapture %}
+
+{% include templates/tutorial.md %}