#146 - Add example to demonstrate Redis Cluster support.

Example demonstrating the basic usage of Spring Data Redis in a clustered environment using Jedis.

redis/cluster/readme.md

@@ -0,0 +1,122 @@
+# Spring Data Redis - Cluster Examples #
+
+This project contains Redis 3 Cluster specific features of Spring Data Redis.
+
+To run the code in this sample a running cluster environment is required. Please refer to the  [redis cluster-tutorial](http://redis.io/topics/cluster-tutorial) for detailed information or check the Cluster Setup section below. 
+
+## Support for Cluster ##
+
+Cluster Support uses the same building blocks as the non clustered counterpart. We use `application.properties` to point to an initial set of known cluster nodes.
+
+```properties
+spring.redis.cluster.nodes[0]=127.0.0.1:30001
+spring.redis.cluster.nodes[1]=127.0.0.1:30002
+spring.redis.cluster.nodes[2]=127.0.0.1:30003
+```
+
+Additionally we need to have the `RedisConnectionFactory` set up with the according `RedisClusterConfiguration`.
+
+```java
+@Configuration
+@EnableConfigurationProperties(ClusterConfigurationProperties.class)
+public class AppConfig {
+
+    /**
+     * Type safe representation of application.properties
+     */
+	@Autowired ClusterConfigurationProperties clusterProperties;
+
+    /**
+     * The connection factory used for obtaining RedisConnection
+     * uses a RedisClusterConfiguration that points
+     * to the initial set of nodes.
+     */
+	@Bean
+	RedisConnectionFactory connectionFactory() {
+		return new JedisConnectionFactory(
+		  new RedisClusterConfiguration(clusterProperties.getNodes()));
+	}
+
+    /**
+     * RedisTemplate can be configured with RedisSerializer if needed.
+     * NOTE: be careful using JSON serializers for key serialization.
+     */
+	@Bean
+	RedisTemplate<String, String> redisTemplate() {
+		return new StringRedisTemplate(connectionFactory());
+	}
+}
+```
+
+**INFORMATION:** The tests flush the db of all known instances during the JUnit _setup_ phase to allow inspecting data directly on the cluster nodes after a test is run.
+
+## Cluster Setup ##
+
+To quickly set up a cluster of 6 nodes (3 master | 3 slave) go to the `redis/utils/create-cluster` directory.
+
+
+```bash
+redis/utils/create-cluster $ ./create-cluster start
+  Starting 30001
+  Starting 30002
+  Starting 30003
+  Starting 30004
+  Starting 30005
+  Starting 30006
+```
+
+On first initialization cluster nodes need to form the cluster by joining and assigning slot allocations.
+**INFO**: This has to be done only once.
+
+```bash
+redis/utils/create-cluster $ ./create-cluster create
+  >>> Creating cluster
+  >>> Performing hash slots allocation on 6 nodes...
+  Using 3 masters:
+    127.0.0.1:30001
+    127.0.0.1:30002
+    127.0.0.1:30003
+  Adding replica 127.0.0.1:30004 to 127.0.0.1:30001
+  Adding replica 127.0.0.1:30005 to 127.0.0.1:30002
+  Adding replica 127.0.0.1:30006 to 127.0.0.1:30003
+
+  M: 10696916f57e58c5edce34127b23ca7af1b669a0 127.0.0.1:30001
+     slots:0-5460 (5461 slots) master
+  M: 5b0e1b4cc87175326ba79d00ecfc6f5dbdb424a7 127.0.0.1:30002
+     slots:5461-10922 (5462 slots) master
+  M: 5f3e978fb40b1d9c910d904ea19a0494b78668aa 127.0.0.1:30003
+     slots:10923-16383 (5461 slots) master
+  S: d1717c418d03db93183ce2d791ba6f48be5cf028 127.0.0.1:30004
+     replicates 10696916f57e58c5edce34127b23ca7af1b669a0
+  S: c7dfcdb9cd1105e4251de51c4ade54de59bb063c 127.0.0.1:30005
+     replicates 5b0e1b4cc87175326ba79d00ecfc6f5dbdb424a7
+  S: 3219785a9145717f30648a27a2dd07359e9dd46f 127.0.0.1:30006
+     replicates 5f3e978fb40b1d9c910d904ea19a0494b78668aa
+
+  Can I set the above configuration? (type 'yes' to accept): yes
+
+  [OK] All nodes agree about slots configuration.
+       >>> Check for open slots...
+       >>> Check slots coverage...
+  [OK] All 16384 slots covered.
+```
+
+It is now possible to connect to the cluster using the `redis-cli`.
+
+```bash
+redis/src $ ./redis-cli -c -p 30001
+  127.0.0.1:30001> cluster nodes
+
+  106969... 127.0.0.1:30001 myself,master - 0 0 1 connected 0-5460
+  5b0e1b... 127.0.0.1:30002 master - 0 1450765112345 2 connected 5461-10922
+  5f3e97... 127.0.0.1:30003 master - 0 1450765112345 3 connected 10923-16383
+  d1717c... 127.0.0.1:30004 slave 106969... 0 1450765112345 4 connected
+  c7dfcd... 127.0.0.1:30005 slave 5b0e1b... 0 1450765113050 5 connected
+  321978... 127.0.0.1:30006 slave 5f3e97... 0 1450765113050 6 connected
+```
+
+To shutdown the cluster use the `create-cluster stop` command.
+
+```bash
+redis/utils/create-cluster $ ./create-cluster stop
+```