Moved hardcoded local datacenter name to config

@@ -184,6 +184,8 @@ cassandra:
   keyspace_name: "${CASSANDRA_KEYSPACE_NAME:thingsboard}"
   # Specify node list
   url: "${CASSANDRA_URL:127.0.0.1:9042}"
+  # Specify local datacenter name
+  local_datacenter: "${CASSANDRA_LOCAL_DATACENTER:datacenter1}"
   # Enable/disable secure connection
   ssl: "${CASSANDRA_USE_SSL:false}"
   # Enable/disable JMX

@@ -36,6 +36,8 @@ public abstract class AbstractCassandraCluster {
     private Boolean jmx;
     @Value("${cassandra.metrics}")
     private Boolean metrics;
+    @Value("${cassandra.local_datacenter}")
+    private String localDatacenter;
 
     @Autowired
     private CassandraDriverOptions driverOptions;
@@ -82,7 +84,7 @@ public abstract class AbstractCassandraCluster {
         if (this.keyspaceName != null) {
             this.sessionBuilder.withKeyspace(this.keyspaceName);
         }
-        this.sessionBuilder.withLocalDatacenter("datacenter1");
+        this.sessionBuilder.withLocalDatacenter(localDatacenter);
         session = sessionBuilder.build();
         if (this.metrics && this.jmx) {
             MetricRegistry registry =