HDFS-11593. Change SimpleHttpProxyHandler#exceptionCaught log level from info to debug. Contributed by Xiaobing Zhou.

(cherry picked from commit 1058b4084392fbc18522ba126313d4a77c09d797)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/SimpleHttpProxyHandler.java

@@ -144,7 +144,9 @@ class SimpleHttpProxyHandler extends SimpleChannelInboundHandler<HttpRequest> {
 
   @Override
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
-    LOG.info("Proxy for " + uri + " failed. cause: ", cause);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Proxy for " + uri + " failed. cause: ", cause);
+    }
     if (proxiedChannel != null) {
       proxiedChannel.close();
       proxiedChannel = null;