HDFS-15380. RBF: Could not fetch real remote IP in RouterWebHdfsMethods. Contributed by tomscut.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterWebHdfsMethods.java

@@ -115,20 +115,18 @@ public class RouterWebHdfsMethods extends NamenodeWebHdfsMethods {
   private static final Logger LOG =
       LoggerFactory.getLogger(RouterWebHdfsMethods.class);
 
-  private static final ThreadLocal<String> REMOTE_ADDRESS =
-      new ThreadLocal<String>();
-
   private @Context HttpServletRequest request;
   private String method;
   private String query;
   private String reqPath;
+  private String remoteAddr;
 
   public RouterWebHdfsMethods(@Context HttpServletRequest request) {
     super(request);
     this.method = request.getMethod();
     this.query = request.getQueryString();
     this.reqPath = request.getServletPath();
-    REMOTE_ADDRESS.set(JspHelper.getRemoteAddr(request));
+    this.remoteAddr = JspHelper.getRemoteAddr(request);
   }
 
   @Override
@@ -139,7 +137,7 @@ public class RouterWebHdfsMethods extends NamenodeWebHdfsMethods {
                       final Param<?, ?>... parameters) {
     super.init(ugi, delegation, username, doAsUser, path, op, parameters);
 
-    REMOTE_ADDRESS.set(JspHelper.getRemoteAddr(request));
+    remoteAddr = JspHelper.getRemoteAddr(request);
   }
 
   @Override
@@ -153,12 +151,12 @@ public class RouterWebHdfsMethods extends NamenodeWebHdfsMethods {
   }
 
   private void reset() {
-    REMOTE_ADDRESS.set(null);
+    remoteAddr = null;
   }
 
   @Override
   protected String getRemoteAddr() {
-    return REMOTE_ADDRESS.get();
+    return remoteAddr;
   }
 
   @Override