HDFS-11846. Ozone: Fix Http connection leaks in ozone clients. Contributed by Weiwei Yang.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/OzoneClientUtils.java

@@ -20,11 +20,16 @@ package org.apache.hadoop.ozone;
 import com.google.common.base.Optional;
 
 import com.google.common.net.HostAndPort;
+import org.apache.avro.reflect.Nullable;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.net.NetUtils;
 import org.apache.hadoop.scm.ScmConfigKeys;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.HttpRequestBase;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -556,4 +561,52 @@ public final class OzoneClientUtils {
         .DFS_CONTAINER_IPC_PORT_DEFAULT);
   }
 
+  /**
+   * Releases a http connection if the request is not null.
+   * @param request
+   */
+  public static void releaseConnection(HttpRequestBase request) {
+    if (request != null) {
+      request.releaseConnection();
+    }
+  }
+
+  /**
+   * @return a default instance of {@link CloseableHttpClient}.
+   */
+  public static CloseableHttpClient newHttpClient() {
+    return OzoneClientUtils.newHttpClient(null);
+  }
+
+  /**
+   * Returns a {@link CloseableHttpClient} configured by given configuration.
+   * If conf is null, returns a default instance.
+   *
+   * @param conf configuration
+   * @return a {@link CloseableHttpClient} instance.
+   */
+  public static CloseableHttpClient newHttpClient(
+      @Nullable Configuration conf) {
+    int socketTimeout = OzoneConfigKeys
+        .OZONE_CLIENT_SOCKET_TIMEOUT_MS_DEFAULT;
+    int connectionTimeout = OzoneConfigKeys
+        .OZONE_CLIENT_CONNECTION_TIMEOUT_MS_DEFAULT;
+    if (conf != null) {
+      socketTimeout = conf.getInt(
+          OzoneConfigKeys.OZONE_CLIENT_SOCKET_TIMEOUT_MS,
+          OzoneConfigKeys.OZONE_CLIENT_SOCKET_TIMEOUT_MS_DEFAULT);
+      connectionTimeout = conf.getInt(
+          OzoneConfigKeys.OZONE_CLIENT_CONNECTION_TIMEOUT_MS,
+          OzoneConfigKeys.OZONE_CLIENT_CONNECTION_TIMEOUT_MS_DEFAULT);
+    }
+
+    CloseableHttpClient client = HttpClients.custom()
+        .setDefaultRequestConfig(
+            RequestConfig.custom()
+                .setSocketTimeout(socketTimeout)
+                .setConnectTimeout(connectionTimeout)
+                .build())
+        .build();
+    return client;
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/OzoneConfigKeys.java

@@ -68,6 +68,13 @@ public final class OzoneConfigKeys {
       "ozone.container.task.wait.seconds";
   public static final long OZONE_CONTAINER_TASK_WAIT_DEFAULT = 5;
 
+  public static final String OZONE_CLIENT_SOCKET_TIMEOUT_MS =
+      "ozone.client.socket.timeout.ms";
+  public static final int OZONE_CLIENT_SOCKET_TIMEOUT_MS_DEFAULT = 5000;
+  public static final String OZONE_CLIENT_CONNECTION_TIMEOUT_MS =
+      "ozone.client.connection.timeout.ms";
+  public static final int OZONE_CLIENT_CONNECTION_TIMEOUT_MS_DEFAULT = 5000;
+
   public static final String DFS_CONTAINER_RATIS_ENABLED_KEY
       = ScmConfigKeys.DFS_CONTAINER_RATIS_ENABLED_KEY;
   public static final boolean DFS_CONTAINER_RATIS_ENABLED_DEFAULT

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/web/client/OzoneBucket.java

@@ -20,6 +20,8 @@ package org.apache.hadoop.ozone.web.client;
 
 import org.apache.commons.codec.digest.DigestUtils;
 import org.apache.hadoop.fs.StorageType;
+import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.ozone.OzoneClientUtils;
 import org.apache.hadoop.ozone.OzoneConsts;
 import org.apache.hadoop.ozone.web.exceptions.OzoneException;
 import org.apache.hadoop.ozone.web.headers.Header;
@@ -37,7 +39,6 @@ import org.apache.http.entity.ContentType;
 import org.apache.http.entity.FileEntity;
 import org.apache.http.entity.InputStreamEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.http.util.EntityUtils;
 
 import java.io.ByteArrayInputStream;
@@ -156,19 +157,16 @@ public class OzoneBucket {
       throw new OzoneClientException("Invalid data.");
     }
 
-    try {
-      OzoneClient client = getVolume().getClient();
-
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpPut putRequest = null;
+    InputStream is = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName()
           + "/" + keyName).build();
 
-      HttpPut putRequest =
-          getVolume().getClient().getHttpPut(builder.toString());
+      putRequest = getVolume().getClient().getHttpPut(builder.toString());
 
-      InputStream is = new ByteArrayInputStream(data.getBytes(ENCODING));
+      is = new ByteArrayInputStream(data.getBytes(ENCODING));
       putRequest.setEntity(new InputStreamEntity(is, data.length()));
       is.mark(data.length());
       try {
@@ -177,9 +175,11 @@ public class OzoneBucket {
         is.reset();
       }
       executePutKey(putRequest, httpClient);
-
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      IOUtils.closeStream(is);
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -216,28 +216,28 @@ public class OzoneBucket {
       throw new OzoneClientException("Invalid data stream");
     }
 
-    try {
-      OzoneClient client = getVolume().getClient();
-
-      CloseableHttpClient httpClient = HttpClients.createDefault();
+    HttpPut putRequest = null;
+    FileInputStream fis = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName()
           + "/" + keyName).build();
 
-      HttpPut putRequest =
-          getVolume().getClient().getHttpPut(builder.toString());
+      putRequest = getVolume().getClient().getHttpPut(builder.toString());
 
       FileEntity fileEntity = new FileEntity(file, ContentType
           .APPLICATION_OCTET_STREAM);
       putRequest.setEntity(fileEntity);
 
-      FileInputStream fis = new FileInputStream(file);
+      fis = new FileInputStream(file);
       putRequest.setHeader(Header.CONTENT_MD5, DigestUtils.md5Hex(fis));
-      fis.close();
       executePutKey(putRequest, httpClient);
 
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      IOUtils.closeStream(fis);
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -253,7 +253,6 @@ public class OzoneBucket {
       throws OzoneException, IOException {
     HttpEntity entity = null;
     try {
-
       HttpResponse response = httpClient.execute(putRequest);
       int errorCode = response.getStatusLine().getStatusCode();
       entity = response.getEntity();
@@ -291,23 +290,23 @@ public class OzoneBucket {
       throw new OzoneClientException("Invalid download path");
     }
 
-    try {
-      OzoneClient client = getVolume().getClient();
-
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-      FileOutputStream outPutFile = new FileOutputStream(downloadTo.toFile());
+    FileOutputStream outPutFile = null;
+    HttpGet getRequest = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
+      outPutFile = new FileOutputStream(downloadTo.toFile());
 
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName()
           + "/" + keyName).build();
 
-      HttpGet getRequest =
-          getVolume().getClient().getHttpGet(builder.toString());
+      getRequest = getVolume().getClient().getHttpGet(builder.toString());
       executeGetKey(getRequest, httpClient, outPutFile);
       outPutFile.flush();
-      outPutFile.close();
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      IOUtils.closeStream(outPutFile);
+      OzoneClientUtils.releaseConnection(getRequest);
     }
   }
 
@@ -324,22 +323,24 @@ public class OzoneBucket {
       throw new OzoneClientException("Invalid key Name");
     }
 
-    try {
-      OzoneClient client = getVolume().getClient();
-      ByteArrayOutputStream outPutStream = new ByteArrayOutputStream();
+    HttpGet getRequest = null;
+    ByteArrayOutputStream outPutStream = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
+      outPutStream = new ByteArrayOutputStream();
 
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
 
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName()
           + "/" + keyName).build();
 
-      HttpGet getRequest =
-          getVolume().getClient().getHttpGet(builder.toString());
+      getRequest = getVolume().getClient().getHttpGet(builder.toString());
       executeGetKey(getRequest, httpClient, outPutStream);
       return outPutStream.toString(ENCODING_NAME);
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      IOUtils.closeStream(outPutStream);
+      OzoneClientUtils.releaseConnection(getRequest);
     }
 
   }
@@ -393,19 +394,19 @@ public class OzoneBucket {
       throw new OzoneClientException("Invalid key Name");
     }
 
-    try {
-      OzoneClient client = getVolume().getClient();
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpDelete deleteRequest = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName()
           + "/" + keyName).build();
 
-      HttpDelete deleteRequest =
-          getVolume().getClient().getHttpDelete(builder.toString());
+      deleteRequest = getVolume()
+          .getClient().getHttpDelete(builder.toString());
       executeDeleteKey(deleteRequest, httpClient);
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(deleteRequest);
     }
   }
 
@@ -450,18 +451,20 @@ public class OzoneBucket {
    * @return List of OzoneKeys
    */
   public List<OzoneKey> listKeys() throws OzoneException {
-    try {
+    HttpGet getRequest = null;
+    try (CloseableHttpClient httpClient = OzoneClientUtils.newHttpClient()) {
       OzoneClient client = getVolume().getClient();
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(volume.getClient().getEndPointURI());
       builder.setPath("/" + getVolume().getVolumeName() + "/" + getBucketName())
           .build();
 
-      HttpGet getRequest = client.getHttpGet(builder.toString());
+      getRequest = client.getHttpGet(builder.toString());
       return executeListKeys(getRequest, httpClient);
 
     } catch (IOException | URISyntaxException e) {
       throw new OzoneClientException(e.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(getRequest);
     }
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/web/client/OzoneClient.java

@@ -17,6 +17,8 @@
  */
 package org.apache.hadoop.ozone.web.client;
 
+import com.google.common.annotations.VisibleForTesting;
+import org.apache.hadoop.ozone.OzoneClientUtils;
 import org.apache.hadoop.ozone.web.exceptions.OzoneException;
 import org.apache.hadoop.ozone.web.headers.Header;
 import org.apache.hadoop.ozone.web.response.ListVolumes;
@@ -32,7 +34,6 @@ import org.apache.http.client.methods.HttpPut;
 import org.apache.http.client.methods.HttpRequestBase;
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.http.util.EntityUtils;
 
 import javax.ws.rs.core.HttpHeaders;
@@ -87,7 +88,6 @@ public class OzoneClient implements Closeable {
    */
   public URI getEndPointURI() {
     return endPointURI;
-
   }
 
   /**
@@ -142,8 +142,8 @@ public class OzoneClient implements Closeable {
    */
   public OzoneVolume createVolume(String volumeName, String onBehalfOf,
                                   String quota) throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
+    HttpPost httpPost = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(volumeName);
 
       URIBuilder builder = new URIBuilder(endPointURI);
@@ -152,11 +152,13 @@ public class OzoneClient implements Closeable {
         builder.setParameter(Header.OZONE_QUOTA_QUERY_TAG, quota);
       }
 
-      HttpPost httppost = getHttpPost(onBehalfOf, builder.build().toString());
-      executeCreateVolume(httppost, httpClient);
+      httpPost = getHttpPost(onBehalfOf, builder.build().toString());
+      executeCreateVolume(httpPost, httpClient);
       return getVolume(volumeName);
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpPost);
     }
   }
 
@@ -169,9 +171,8 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   public OzoneVolume getVolume(String volumeName) throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpGet httpGet = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(volumeName);
       URIBuilder builder = new URIBuilder(endPointURI);
       builder.setPath("/" + volumeName)
@@ -179,11 +180,12 @@ public class OzoneClient implements Closeable {
               Header.OZONE_LIST_QUERY_VOLUME)
           .build();
 
-      HttpGet httpget = getHttpGet(builder.toString());
-      return executeInfoVolume(httpget, httpClient);
-
+      httpGet = getHttpGet(builder.toString());
+      return executeInfoVolume(httpGet, httpClient);
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpGet);
     }
   }
 
@@ -205,9 +207,8 @@ public class OzoneClient implements Closeable {
    */
   public List<OzoneVolume> listVolumes(String onBehalfOf, String prefix, int
       maxKeys, OzoneVolume prevKey) throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpGet httpGet = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       URIBuilder builder = new URIBuilder(endPointURI);
       if (prefix != null) {
         builder.addParameter(Header.OZONE_LIST_QUERY_PREFIX, prefix);
@@ -225,14 +226,15 @@ public class OzoneClient implements Closeable {
 
       builder.setPath("/").build();
 
-      HttpGet httpget = getHttpGet(builder.toString());
+      httpGet = getHttpGet(builder.toString());
       if (onBehalfOf != null) {
-        httpget.addHeader(Header.OZONE_USER, onBehalfOf);
+        httpGet.addHeader(Header.OZONE_USER, onBehalfOf);
       }
-      return executeListVolume(httpget, httpClient);
-
+      return executeListVolume(httpGet, httpClient);
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpGet);
     }
   }
 
@@ -261,9 +263,8 @@ public class OzoneClient implements Closeable {
    */
   public List<OzoneVolume> listAllVolumes(String prefix, int maxKeys,
       OzoneVolume prevKey) throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpGet httpGet = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       URIBuilder builder = new URIBuilder(endPointURI);
       if (prefix != null) {
         builder.addParameter(Header.OZONE_LIST_QUERY_PREFIX, prefix);
@@ -281,11 +282,13 @@ public class OzoneClient implements Closeable {
 
       builder.addParameter(Header.OZONE_LIST_QUERY_ROOTSCAN, "true");
       builder.setPath("/").build();
-      HttpGet httpget = getHttpGet(builder.toString());
-      return executeListVolume(httpget, httpClient);
+      httpGet = getHttpGet(builder.toString());
+      return executeListVolume(httpGet, httpClient);
 
     } catch (IOException | URISyntaxException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpGet);
     }
   }
 
@@ -296,17 +299,18 @@ public class OzoneClient implements Closeable {
      * @throws OzoneException - Ozone Exception
      */
   public void deleteVolume(String volumeName) throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpDelete httpDelete = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(volumeName);
       URIBuilder builder = new URIBuilder(endPointURI);
       builder.setPath("/" + volumeName).build();
 
-      HttpDelete httpdelete = getHttpDelete(builder.toString());
-      executeDeleteVolume(httpdelete, httpClient);
+      httpDelete = getHttpDelete(builder.toString());
+      executeDeleteVolume(httpDelete, httpClient);
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpDelete);
     }
   }
 
@@ -319,23 +323,23 @@ public class OzoneClient implements Closeable {
    */
   public void setVolumeOwner(String volumeName, String newOwner)
       throws OzoneException {
-
+    HttpPut putRequest = null;
     if (newOwner == null || newOwner.isEmpty()) {
       throw new OzoneClientException("Invalid new owner name");
     }
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(volumeName);
       URIBuilder builder = new URIBuilder(endPointURI);
       builder.setPath("/" + volumeName).build();
 
-      HttpPut putRequest = getHttpPut(builder.toString());
+      putRequest = getHttpPut(builder.toString());
       putRequest.addHeader(Header.OZONE_USER, newOwner);
       executePutVolume(putRequest, httpClient);
 
     } catch (URISyntaxException | IllegalArgumentException | IOException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -354,20 +358,21 @@ public class OzoneClient implements Closeable {
     if (quota == null || quota.isEmpty()) {
       throw new OzoneClientException("Invalid quota");
     }
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpPut putRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(volumeName);
       URIBuilder builder = new URIBuilder(endPointURI);
       builder.setPath("/" + volumeName)
           .setParameter(Header.OZONE_QUOTA_QUERY_TAG, quota)
           .build();
 
-      HttpPut putRequest = getHttpPut(builder.toString());
+      putRequest = getHttpPut(builder.toString());
       executePutVolume(putRequest, httpClient);
 
     } catch (URISyntaxException | IllegalArgumentException | IOException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -380,7 +385,7 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   private void executeCreateVolume(HttpPost httppost,
-      CloseableHttpClient httpClient)
+      final CloseableHttpClient httpClient)
       throws IOException, OzoneException {
     HttpEntity entity = null;
     try {
@@ -413,7 +418,7 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   private OzoneVolume executeInfoVolume(HttpGet httpGet,
-      CloseableHttpClient httpClient)
+      final CloseableHttpClient httpClient)
       throws IOException, OzoneException {
     HttpEntity entity = null;
     try {
@@ -447,7 +452,7 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   private void executePutVolume(HttpPut putRequest,
-      CloseableHttpClient httpClient)
+      final CloseableHttpClient httpClient)
       throws IOException, OzoneException {
     HttpEntity entity = null;
     try {
@@ -473,7 +478,7 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   private List<OzoneVolume> executeListVolume(HttpGet httpGet,
-      CloseableHttpClient httpClient)
+      final CloseableHttpClient httpClient)
       throws IOException, OzoneException {
     HttpEntity entity = null;
     List<OzoneVolume> volList = new LinkedList<>();
@@ -514,7 +519,7 @@ public class OzoneClient implements Closeable {
    * @throws OzoneException
    */
   private void executeDeleteVolume(HttpDelete httpDelete,
-      CloseableHttpClient httpClient)
+      final CloseableHttpClient httpClient)
       throws IOException, OzoneException {
     HttpEntity entity = null;
     try {
@@ -540,12 +545,12 @@ public class OzoneClient implements Closeable {
    * @return HttpPost
    */
   public HttpPost getHttpPost(String onBehalfOf, String uriString) {
-    HttpPost httppost = new HttpPost(uriString);
-    addOzoneHeaders(httppost);
+    HttpPost httpPost = new HttpPost(uriString);
+    addOzoneHeaders(httpPost);
     if (onBehalfOf != null) {
-      httppost.addHeader(Header.OZONE_USER, onBehalfOf);
+      httpPost.addHeader(Header.OZONE_USER, onBehalfOf);
     }
-    return httppost;
+    return httpPost;
   }
 
   /**
@@ -555,9 +560,9 @@ public class OzoneClient implements Closeable {
    * @return HttpGet
    */
   public HttpGet getHttpGet(String uriString) {
-    HttpGet httpget = new HttpGet(uriString);
-    addOzoneHeaders(httpget);
-    return httpget;
+    HttpGet httpGet = new HttpGet(uriString);
+    addOzoneHeaders(httpGet);
+    return httpGet;
   }
 
   /**
@@ -615,4 +620,9 @@ public class OzoneClient implements Closeable {
     // TODO : Currently we create a new HTTP client. We should switch
     // This to a Pool and cleanup the pool here.
   }
+
+  @VisibleForTesting
+  public CloseableHttpClient newHttpClient() {
+    return OzoneClientUtils.newHttpClient();
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/web/client/OzoneVolume.java

@@ -18,7 +18,9 @@
 
 package org.apache.hadoop.ozone.web.client;
 
+import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.fs.StorageType;
+import org.apache.hadoop.ozone.OzoneClientUtils;
 import org.apache.hadoop.ozone.web.exceptions.OzoneException;
 import org.apache.hadoop.ozone.web.headers.Header;
 import org.apache.hadoop.ozone.web.request.OzoneQuota;
@@ -35,7 +37,6 @@ import org.apache.http.client.methods.HttpPost;
 import org.apache.http.client.methods.HttpPut;
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.http.util.EntityUtils;
 
 import java.io.IOException;
@@ -164,26 +165,28 @@ public class OzoneVolume {
                                   OzoneConsts.Versioning versioning)
       throws OzoneException {
 
-    try {
+    HttpPost httpPost = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(bucketName);
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName() + "/" + bucketName).build();
 
-      HttpPost httppost = client.getHttpPost(null, builder.toString());
+      httpPost = client.getHttpPost(null, builder.toString());
       if (acls != null) {
         for (String acl : acls) {
-          httppost
+          httpPost
               .addHeader(Header.OZONE_ACLS, Header.OZONE_ACL_ADD + " " + acl);
         }
       }
 
-      httppost.addHeader(Header.OZONE_STORAGE_TYPE, storageType.toString());
-      httppost.addHeader(Header.OZONE_BUCKET_VERSIONING, versioning.toString());
-      executeCreateBucket(httppost, httpClient);
+      httpPost.addHeader(Header.OZONE_STORAGE_TYPE, storageType.toString());
+      httpPost.addHeader(Header.OZONE_BUCKET_VERSIONING, versioning.toString());
+      executeCreateBucket(httpPost, httpClient);
       return getBucket(bucketName);
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(httpPost);
     }
   }
 
@@ -226,7 +229,6 @@ public class OzoneVolume {
    * @throws OzoneException
    */
   public OzoneBucket createBucket(String bucketName) throws OzoneException {
-
     return createBucket(bucketName, null,  StorageType.DEFAULT,
         OzoneConsts.Versioning.DISABLED);
   }
@@ -273,13 +275,12 @@ public class OzoneVolume {
    * @throws OzoneException
    */
   public void addAcls(String bucketName, String[] acls) throws OzoneException {
-
-    try {
+    HttpPut putRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(bucketName);
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName() + "/" + bucketName).build();
-      HttpPut putRequest = client.getHttpPut(builder.toString());
+      putRequest = client.getHttpPut(builder.toString());
 
       for (String acl : acls) {
         putRequest
@@ -288,6 +289,8 @@ public class OzoneVolume {
       executePutBucket(putRequest, httpClient);
     } catch (URISyntaxException | IOException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -301,12 +304,12 @@ public class OzoneVolume {
    */
   public void removeAcls(String bucketName, String[] acls)
       throws OzoneException {
-    try {
+    HttpPut putRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(bucketName);
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName() + "/" + bucketName).build();
-      HttpPut putRequest = client.getHttpPut(builder.toString());
+      putRequest = client.getHttpPut(builder.toString());
 
       for (String acl : acls) {
         putRequest
@@ -315,6 +318,8 @@ public class OzoneVolume {
       executePutBucket(putRequest, httpClient);
     } catch (URISyntaxException | IOException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(putRequest);
     }
   }
 
@@ -326,18 +331,20 @@ public class OzoneVolume {
    * @return OZoneBucket
    */
   public OzoneBucket getBucket(String bucketName) throws OzoneException {
-    try {
+    HttpGet getRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(bucketName);
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName() + "/" + bucketName)
         .setParameter(Header.OZONE_LIST_QUERY_TAG,
             Header.OZONE_LIST_QUERY_BUCKET).build();
-      HttpGet getRequest = client.getHttpGet(builder.toString());
+      getRequest = client.getHttpGet(builder.toString());
       return executeInfoBucket(getRequest, httpClient);
 
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(getRequest);
     }
   }
 
@@ -422,17 +429,18 @@ public class OzoneVolume {
    * @throws OzoneException
    */
   public List<OzoneBucket> listBuckets() throws OzoneException {
-    try {
-      CloseableHttpClient httpClient = HttpClients.createDefault();
-
+    HttpGet getRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName()).build();
 
-      HttpGet getRequest = client.getHttpGet(builder.toString());
+      getRequest = client.getHttpGet(builder.toString());
       return executeListBuckets(getRequest, httpClient);
 
     } catch (IOException | URISyntaxException e) {
       throw new OzoneClientException(e.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(getRequest);
     }
   }
 
@@ -488,17 +496,19 @@ public class OzoneVolume {
    * @throws OzoneException
    */
   public void deleteBucket(String bucketName) throws OzoneException {
-    try {
+    HttpDelete delRequest = null;
+    try (CloseableHttpClient httpClient = newHttpClient()) {
       OzoneUtils.verifyBucketName(bucketName);
-      CloseableHttpClient httpClient = HttpClients.createDefault();
       URIBuilder builder = new URIBuilder(getClient().getEndPointURI());
       builder.setPath("/" + getVolumeName() + "/" + bucketName).build();
 
-      HttpDelete delRequest = client.getHttpDelete(builder.toString());
+      delRequest = client.getHttpDelete(builder.toString());
       executeDeleteBucket(delRequest, httpClient);
 
     } catch (IOException | URISyntaxException | IllegalArgumentException ex) {
       throw new OzoneClientException(ex.getMessage());
+    } finally {
+      OzoneClientUtils.releaseConnection(delRequest);
     }
   }
 
@@ -536,4 +546,9 @@ public class OzoneVolume {
       }
     }
   }
+
+  @VisibleForTesting
+  public CloseableHttpClient newHttpClient() {
+    return OzoneClientUtils.newHttpClient();
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/ozone/web/client/TestVolume.java

@@ -22,28 +22,36 @@ import org.apache.commons.io.FileUtils;
 import org.apache.commons.lang.RandomStringUtils;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.ozone.MiniOzoneCluster;
-import org.apache.hadoop.ozone.OzoneConfigKeys;
 import org.apache.hadoop.ozone.OzoneConfiguration;
+import org.apache.hadoop.ozone.OzoneConfigKeys;
+import org.apache.hadoop.ozone.OzoneConsts;
+import org.apache.hadoop.ozone.OzoneClientUtils;
 import org.apache.hadoop.ozone.web.exceptions.OzoneException;
 import org.apache.hadoop.ozone.web.request.OzoneQuota;
-import org.apache.hadoop.ozone.OzoneConsts;
 import org.apache.hadoop.ozone.web.utils.OzoneUtils;
 import org.apache.hadoop.test.GenericTestUtils;
+import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.log4j.Level;
 import org.apache.log4j.Logger;
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 public class TestVolume {
   private static MiniOzoneCluster cluster = null;
@@ -90,10 +98,15 @@ public class TestVolume {
   }
 
   @Test
-  public void testCreateVolume() throws OzoneException {
+  public void testCreateVolume() throws OzoneException, IOException {
     String volumeName = OzoneUtils.getRequestID().toLowerCase();
     client.setUserAuth(OzoneConsts.OZONE_SIMPLE_HDFS_USER);
-    OzoneVolume vol = client.createVolume(volumeName, "bilbo", "100TB");
+
+    OzoneClient mockClient = Mockito.spy(client);
+    List<CloseableHttpClient> mockedClients = mockHttpClients(mockClient);
+    OzoneVolume vol = mockClient.createVolume(volumeName, "bilbo", "100TB");
+    // Verify http clients are properly closed.
+    verifyHttpConnectionClosed(mockedClients);
 
     assertEquals(vol.getVolumeName(), volumeName);
     assertEquals(vol.getCreatedby(), "hdfs");
@@ -210,4 +223,80 @@ public class TestVolume {
     // be volumes created by other tests too. So we should get more page counts.
     Assert.assertEquals(volCount / step , pagecount);
   }
+
+  /**
+   * Returns a list of mocked {@link CloseableHttpClient} used for testing.
+   * The mocked client replaces the actual calls in
+   * {@link OzoneClient#newHttpClient()}, it is used to verify
+   * if the invocation of this client is expected. <b>Note</b>, the output
+   * of this method is always used as the input of
+   * {@link TestVolume#verifyHttpConnectionClosed(List)}.
+   *
+   * @param ozoneClient mocked ozone client.
+   * @return a list of mocked {@link CloseableHttpClient}.
+   * @throws IOException
+   */
+  private List<CloseableHttpClient> mockHttpClients(OzoneClient ozoneClient)
+      throws IOException {
+    List<CloseableHttpClient> spyHttpClients = new ArrayList<>();
+    for (int i = 0; i < 5; i++) {
+      CloseableHttpClient spyHttpClient = Mockito
+          .spy(OzoneClientUtils.newHttpClient());
+      spyHttpClients.add(spyHttpClient);
+    }
+
+    List<CloseableHttpClient> nextReturns =
+        new ArrayList<>(spyHttpClients.subList(1, spyHttpClients.size()));
+    Mockito.when(ozoneClient.newHttpClient()).thenReturn(
+        spyHttpClients.get(0),
+        nextReturns.toArray(new CloseableHttpClient[nextReturns.size()]));
+    return spyHttpClients;
+  }
+
+  /**
+   * This method is used together with
+   * {@link TestVolume#mockHttpClients(OzoneClient)} to verify
+   * if the http client is properly closed. It verifies that as long as
+   * a client calls {@link CloseableHttpClient#execute(HttpUriRequest)} to
+   * send request, then it must calls {@link CloseableHttpClient#close()}
+   * close the http connection.
+   *
+   * @param mockedHttpClients
+   */
+  private void verifyHttpConnectionClosed(
+      List<CloseableHttpClient> mockedHttpClients) {
+    final AtomicInteger totalCalled = new AtomicInteger();
+    Assert.assertTrue(mockedHttpClients.stream().allMatch(
+        closeableHttpClient -> {
+          boolean clientUsed = false;
+          try {
+            verify(closeableHttpClient, times(1))
+                .execute(Mockito.any());
+            totalCalled.incrementAndGet();
+            clientUsed = true;
+          } catch (Throwable e) {
+            // There might be some redundant instances in mockedHttpClients,
+            // it is allowed that a client is not used.
+            return true;
+          }
+
+          if (clientUsed) {
+            try {
+              // If a client is used, ensure the close function is called.
+              verify(closeableHttpClient,
+                  times(1)).close();
+              return true;
+            } catch (IOException e) {
+              return false;
+            }
+          } else {
+            return true;
+          }
+        }));
+    System.out.println("Successful connections "
+        + totalCalled.get());
+    Assert.assertTrue(
+        "The mocked http client should be called at least once.",
+        totalCalled.get() > 0);
+  }
 }