- [x] I have searched the [issues](https://github.com/apache/incubator-dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/incubator-dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.


### Environment

* Dubbo version: 2.7.2-SNAPSHOT
* Operating System version: windows1
* Java version: 1.8

### Steps to reproduce this issue
```java
public class RedisMetadataReport extends AbstractMetadataReport {

    private final static Logger logger = LoggerFactory.getLogger(RedisMetadataReport.class);

    final JedisPool pool;

    public RedisMetadataReport(URL url) {
        super(url);
        pool = new JedisPool(new JedisPoolConfig(), url.getHost(), url.getPort());
    }
}
```
I see the construct method used `JedisPool`, 
**if cluster ，how should  do？**

public static final String SEPARATOR = ":";
    final static String DEFAULT_PATH_TAG = "metadata";
    final static String META_DATA_STORE_TAG = ".metaData";
    private String serviceInterface;
    private String version;
    private String group;
    private String side;
    private String application;
    public MetadataIdentifier() {
    }
    public MetadataIdentifier(String serviceInterface, String version, String group, String side, String application) {
        this.serviceInterface = serviceInterface;
        this.version = version;
        this.group = group;
        this.side = side;
        this.application = application;
    }
    public MetadataIdentifier(URL url) {
        this.serviceInterface = url.getServiceInterface();
        this.version = url.getParameter(VERSION_KEY);
        this.group = url.getParameter(GROUP_KEY);