HDDS-1596. Create service endpoint to download configuration from SCM.

Signed-off-by: Anu Engineer <aengineer@apache.org>

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/conf/OzoneConfiguration.java

@@ -47,19 +47,43 @@ public class OzoneConfiguration extends Configuration {
   }
 
   public OzoneConfiguration() {
+    this(false);
+  }
+
+  private OzoneConfiguration(boolean justTheDefaults) {
     OzoneConfiguration.activate();
     loadDefaults();
+    if (!justTheDefaults) {
+      loadConfigFiles();
+    }
+  }
+
+  private void loadConfigFiles() {
+    addResource("ozone-global.xml");
+    addResource("ozone-site.xml");
   }
 
   public OzoneConfiguration(Configuration conf) {
+    this(conf, false);
+  }
+
+  private OzoneConfiguration(Configuration conf, boolean justTheDefaults) {
     super(conf);
     //load the configuration from the classloader of the original conf.
     setClassLoader(conf.getClassLoader());
     if (!(conf instanceof OzoneConfiguration)) {
       loadDefaults();
+      //here we load the REAL configuration.
+      if (!justTheDefaults) {
+        loadConfigFiles();
+      }
     }
   }
 
+  public static OzoneConfiguration createWithDefaultsOnly() {
+    return new OzoneConfiguration(true);
+  }
+
   private void loadDefaults() {
     try {
       //there could be multiple ozone-default-generated.xml files on the
@@ -74,7 +98,6 @@ public class OzoneConfiguration extends Configuration {
     } catch (IOException e) {
       e.printStackTrace();
     }
-    addResource("ozone-site.xml");
   }
 
   public List<Property> readPropertyFromXml(URL url) throws JAXBException {
@@ -316,4 +339,9 @@ public class OzoneConfiguration extends Configuration {
     }
     return props;
   }
+
+  @Override
+  public synchronized Properties getProps() {
+    return super.getProps();
+  }
 }

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/discovery/DiscoveryUtil.java

@@ -0,0 +1,90 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdds.discovery;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.net.URL;
+import java.nio.channels.Channels;
+import java.nio.channels.ReadableByteChannel;
+
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utility to download ozone configuration from SCM.
+ */
+public final class DiscoveryUtil {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(DiscoveryUtil.class);
+
+  public static final String OZONE_GLOBAL_XML = "ozone-global.xml";
+
+  private DiscoveryUtil() {
+  }
+
+  /**
+   * Download ozone-global.conf from SCM to the local HADOOP_CONF_DIR.
+   */
+  public static boolean loadGlobalConfig(OzoneConfiguration conf) {
+    String hadoopConfDir = System.getenv("HADOOP_CONF_DIR");
+    if (hadoopConfDir == null || hadoopConfDir.isEmpty()) {
+      LOG.warn(
+          "HADOOP_CONF_DIR is not set, can't download ozone-global.xml from "
+              + "SCM.");
+      return false;
+    }
+    if (conf.get("ozone.scm.names") == null) {
+      LOG.warn("ozone.scm.names is not set. Can't download config from scm.");
+      return false;
+    }
+    for (int i = 0; i < 60; i++) {
+      for (String scmHost : conf.getStrings("ozone.scm.names")) {
+        String configOrigin =
+            String.format("http://%s:9876/discovery/config", scmHost);
+        File destinationFile = new File(hadoopConfDir, OZONE_GLOBAL_XML);
+
+        try {
+          LOG.info("Downloading {} to {}", configOrigin,
+              destinationFile.getAbsolutePath());
+          URL confUrl = new URL(configOrigin);
+          ReadableByteChannel rbc = Channels.newChannel(confUrl.openStream());
+          FileOutputStream fos =
+              new FileOutputStream(
+                  destinationFile);
+          fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+          return true;
+        } catch (Exception ex) {
+          LOG.error("Can't download config from " + configOrigin, ex);
+        }
+      }
+      LOG.warn(
+          "Configuration download was unsuccessful. Let's wait 5 seconds and"
+              + " retry.");
+      try {
+        Thread.sleep(5000);
+      } catch (InterruptedException e) {
+        LOG.error("Polling the config file upload is interrupted", e);
+      }
+    }
+    return false;
+  }
+}

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/discovery/package-info.java

@@ -0,0 +1,22 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership.  The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.apache.hadoop.hdds.discovery;
+
+/*
+ * Discovery/config service related classes.
+ */

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/HddsDatanodeService.java

@@ -25,6 +25,7 @@ import org.apache.hadoop.hdds.HddsUtils;
 import org.apache.hadoop.hdds.cli.GenericCli;
 import org.apache.hadoop.hdds.cli.HddsVersionProvider;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.discovery.DiscoveryUtil;
 import org.apache.hadoop.hdds.protocol.DatanodeDetails;
 import org.apache.hadoop.hdds.protocol.proto.SCMSecurityProtocolProtos.SCMGetCertResponseProto;
 import org.apache.hadoop.hdds.protocolPB.SCMSecurityProtocolClientSideTranslatorPB;
@@ -140,7 +141,12 @@ public class HddsDatanodeService extends GenericCli implements ServicePlugin {
       StringUtils
           .startupShutdownMessage(HddsDatanodeService.class, args, LOG);
     }
-    start(createOzoneConfiguration());
+    OzoneConfiguration ozoneConfiguration = createOzoneConfiguration();
+    if (DiscoveryUtil.loadGlobalConfig(ozoneConfiguration)) {
+      //reload the configuration with the downloaded new configs.
+      ozoneConfiguration = createOzoneConfiguration();
+    }
+    start(ozoneConfiguration);
     join();
     return null;
   }

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/server/BaseHttpServer.java

@@ -33,6 +33,7 @@ import org.slf4j.LoggerFactory;
 import javax.servlet.http.HttpServlet;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.util.Map;
 import java.util.Optional;
 
 import static org.apache.hadoop.hdds.HddsUtils.getHostNameFromConfigKeys;
@@ -127,6 +128,18 @@ public abstract class BaseHttpServer {
     httpServer.addServlet(servletName, pathSpec, clazz);
   }
 
+  /**
+   * Add a servlet to BaseHttpServer.
+   *
+   * @param servletName The name of the servlet
+   * @param pathSpec    The path spec for the servlet
+   * @param clazz       The servlet class
+   */
+  protected void addInternalServlet(String servletName, String pathSpec,
+      Class<? extends HttpServlet> clazz, Map<String, String> initParams) {
+    httpServer.addInternalServlet(servletName, pathSpec, clazz, initParams);
+  }
+
   /**
    * Returns the WebAppContext associated with this HttpServer.
    *

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/server/ServerUtils.java

@@ -96,7 +96,17 @@ public final class ServerUtils {
         rpcServer.getListenerAddress());
   }
 
-
+  public static InetSocketAddress updateRPCListenPort(
+      OzoneConfiguration conf, String rpcAddressKey,
+      InetSocketAddress listenerAddress) {
+    String originalValue = conf.get(rpcAddressKey);
+    //remove existing port
+    originalValue = originalValue.replaceAll(":.*", "");
+    conf.set(rpcAddressKey,
+        originalValue + ":" + listenerAddress.getPort());
+    return new InetSocketAddress(originalValue,
+        listenerAddress.getPort());
+  }
   /**
    * After starting an server, updates configuration with the actual
    * listening address of that server. The listening address may be different

hadoop-hdds/framework/src/test/java/org/apache/hadoop/hdds/server/TestServerUtils.java

@@ -23,11 +23,14 @@ import org.apache.hadoop.hdds.HddsConfigKeys;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
 import org.apache.hadoop.hdds.scm.ScmConfigKeys;
 import org.apache.hadoop.test.PathUtils;
+
+import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 import java.io.File;
+import java.net.InetSocketAddress;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -120,4 +123,18 @@ public class TestServerUtils {
     ServerUtils.getOzoneMetaDirPath(conf);
   }
 
+  @Test
+  public void updateRpcListenPort() {
+    OzoneConfiguration conf = new OzoneConfiguration();
+
+    conf.set("test1", "localhost:0");
+    ServerUtils.updateRPCListenPort(conf, "test1",
+        new InetSocketAddress("0.0.0.0", 1234));
+    Assert.assertEquals("localhost:1234", conf.get("test1"));
+
+    conf.set("test2", "localhost");
+    ServerUtils.updateRPCListenPort(conf, "test2",
+        new InetSocketAddress("0.0.0.0", 1234));
+    Assert.assertEquals("localhost:1234", conf.get("test2"));
+  }
 }

hadoop-hdds/pom.xml

@@ -191,6 +191,27 @@ https://maven.apache.org/xsd/maven-4.0.0.xsd">
         <version>${bouncycastle.version}</version>
       </dependency>
 
+      <dependency>
+        <groupId>com.sun.xml.bind</groupId>
+        <artifactId>jaxb-impl</artifactId>
+        <version>2.3.0.1</version>
+      </dependency>
+      <dependency>
+        <groupId>com.sun.xml.bind</groupId>
+        <artifactId>jaxb-core</artifactId>
+        <version>2.3.0.1</version>
+      </dependency>
+      <dependency>
+        <groupId>javax.xml.bind</groupId>
+        <artifactId>jaxb-api</artifactId>
+        <version>2.3.0</version>
+      </dependency>
+      <dependency>
+        <groupId>javax.activation</groupId>
+        <artifactId>activation</artifactId>
+        <version>1.1.1</version>
+      </dependency>
+
       <dependency>
         <groupId>org.junit.jupiter</groupId>
         <artifactId>junit-jupiter-api</artifactId>

hadoop-hdds/server-scm/pom.xml

@@ -54,6 +54,24 @@ https://maven.apache.org/xsd/maven-4.0.0.xsd">
       <artifactId>hadoop-hdds-docs</artifactId>
     </dependency>
 
+    <dependency>
+      <groupId>com.sun.xml.bind</groupId>
+      <artifactId>jaxb-impl</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>com.sun.xml.bind</groupId>
+      <artifactId>jaxb-core</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>javax.xml.bind</groupId>
+      <artifactId>jaxb-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>javax.activation</groupId>
+      <artifactId>activation</artifactId>
+    </dependency>
+
+
     <dependency>
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-hdds-container-service</artifactId>

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/discovery/ConfigurationEndpoint.java

@@ -0,0 +1,60 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdds.discovery;
+
+import javax.servlet.ServletContext;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+
+import java.util.Map.Entry;
+import java.util.Properties;
+
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.scm.server.StorageContainerManagerHttpServer;
+
+/**
+ * JAXRS endpoint to publish current ozone configuration.
+ */
+@Path("/config")
+public class ConfigurationEndpoint {
+
+  private Properties defaults =
+      OzoneConfiguration.createWithDefaultsOnly().getProps();
+
+  @javax.ws.rs.core.Context
+  private ServletContext context;
+
+  /**
+   * Returns with the non-default configuration.
+   */
+  @GET
+  public ConfigurationXml getConfiguration() {
+    OzoneConfiguration conf = (OzoneConfiguration) context.getAttribute(
+        StorageContainerManagerHttpServer.CONFIG_CONTEXT_ATTRIBUTE);
+    ConfigurationXml configXml = new ConfigurationXml();
+    for (Entry<Object, Object> entry : conf.getProps().entrySet()) {
+      //return only the non-defaults
+      if (defaults.get(entry.getKey()) != entry.getValue()) {
+        configXml.addConfiguration(entry.getKey().toString(),
+            entry.getValue().toString());
+      }
+    }
+    return configXml;
+  }
+
+}

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/discovery/ConfigurationXml.java

@@ -0,0 +1,44 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdds.discovery;
+
+import javax.xml.bind.annotation.XmlRootElement;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * JAXB representation of Hadoop Configuration.
+ */
+@XmlRootElement(name = "configuration")
+public class ConfigurationXml {
+
+  private List<ConfigurationXmlEntry> property = new ArrayList<>();
+
+  public List<ConfigurationXmlEntry> getProperty() {
+    return property;
+  }
+
+  public void setProperty(
+      List<ConfigurationXmlEntry> property) {
+    this.property = property;
+  }
+
+  public void addConfiguration(String key, String name) {
+    property.add(new ConfigurationXmlEntry(key, name));
+  }
+}

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/discovery/ConfigurationXmlEntry.java

@@ -0,0 +1,56 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdds.discovery;
+
+import javax.xml.bind.annotation.XmlElement;
+
+/**
+ * JAXB representation of one property of a hadoop configuration XML.
+ */
+public class ConfigurationXmlEntry {
+
+  @XmlElement
+  private String name;
+
+  @XmlElement
+  private String value;
+
+  public ConfigurationXmlEntry() {
+  }
+
+  public ConfigurationXmlEntry(String name, String value) {
+    this.name = name;
+    this.value = value;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public void setValue(String value) {
+    this.value = value;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public String getValue() {
+    return value;
+  }
+}

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/discovery/DiscoveryApplication.java

@@ -0,0 +1,35 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdds.discovery;
+
+import javax.ws.rs.core.Application;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * JAXRS resource file registration.
+ */
+public class DiscoveryApplication extends Application {
+
+  @Override
+  public Set<Class<?>> getClasses() {
+    Set<Class<?>> classes = new HashSet<>();
+    classes.add(DiscoveryApplication.class);
+    return classes;
+  }
+}

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/discovery/package-info.java

@@ -0,0 +1,22 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership.  The ASF
+ * licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package org.apache.hadoop.hdds.discovery;
+
+/*
+ * Discovery/config service related classes.
+ */

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/server/SCMBlockProtocolServer.java

@@ -54,6 +54,8 @@ import org.apache.hadoop.hdds.client.BlockID;
 import org.apache.hadoop.ozone.common.DeleteBlockGroupResult;
 import org.apache.hadoop.ozone.protocolPB
     .ScmBlockLocationProtocolServerSideTranslatorPB;
+
+import static org.apache.hadoop.hdds.server.ServerUtils.updateRPCListenPort;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -69,7 +71,6 @@ import static org.apache.hadoop.hdds.scm.ScmConfigKeys
     .OZONE_SCM_HANDLER_COUNT_DEFAULT;
 import static org.apache.hadoop.hdds.scm.ScmConfigKeys
     .OZONE_SCM_HANDLER_COUNT_KEY;
-import static org.apache.hadoop.hdds.server.ServerUtils.updateRPCListenAddress;
 import static org.apache.hadoop.hdds.scm.server.StorageContainerManager
     .startRpcServer;
 
@@ -119,9 +120,9 @@ public class SCMBlockProtocolServer implements
             blockProtoPbService,
             handlerCount);
     blockRpcAddress =
-        updateRPCListenAddress(
-            conf, OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY, scmBlockAddress,
-            blockRpcServer);
+        updateRPCListenPort(
+            conf, OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY,
+            blockRpcServer.getListenerAddress());
     if (conf.getBoolean(CommonConfigurationKeys.HADOOP_SECURITY_AUTHORIZATION,
         false)) {
       blockRpcServer.refreshServiceAcl(conf, SCMPolicyProvider.getInstance());

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/server/StorageContainerManagerHttpServer.java

@@ -17,20 +17,33 @@
 
 package org.apache.hadoop.hdds.scm.server;
 
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdds.scm.ScmConfigKeys;
 import org.apache.hadoop.hdds.server.BaseHttpServer;
 
-import java.io.IOException;
+import com.sun.jersey.spi.container.servlet.ServletContainer;
 
 /**
  * HttpServer2 wrapper for the Ozone Storage Container Manager.
  */
 public class StorageContainerManagerHttpServer extends BaseHttpServer {
 
+  public static final String CONFIG_CONTEXT_ATTRIBUTE = "ozone.configuration";
+
   public StorageContainerManagerHttpServer(Configuration conf)
       throws IOException {
     super(conf, "scm");
+    Map<String, String> initParameters = new HashMap<>();
+    initParameters.put("com.sun.jersey.config.property.packages",
+        "org.apache.hadoop.hdds.discovery");
+    addInternalServlet("rest", "/discovery/*", ServletContainer.class,
+        initParameters);
+    getWebAppContext().setAttribute(CONFIG_CONTEXT_ATTRIBUTE, conf);
+
   }
 
   @Override protected String getHttpAddressKey() {

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/server/StorageContainerManagerStarter.java

@@ -24,6 +24,7 @@ package org.apache.hadoop.hdds.scm.server;
 import org.apache.hadoop.hdds.cli.GenericCli;
 import org.apache.hadoop.hdds.cli.HddsVersionProvider;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.discovery.DiscoveryUtil;
 import org.apache.hadoop.hdds.tracing.TracingUtil;
 import org.apache.hadoop.ozone.common.StorageInfo;
 import org.apache.hadoop.util.StringUtils;
@@ -121,6 +122,10 @@ public class StorageContainerManagerStarter extends GenericCli {
    */
   private void commonInit() {
     conf = createOzoneConfiguration();
+    if (DiscoveryUtil.loadGlobalConfig(conf)) {
+      //reload the configuration with the downloaded new configs.
+      conf = createOzoneConfiguration();
+    }
 
     String[] originalArgs = getCmd().getParseResult().originalArgs()
         .toArray(new String[0]);

hadoop-ozone/dist/src/main/compose/ozone/docker-compose.yaml

@@ -25,6 +25,8 @@ services:
         - 9864
         - 9882
       command: ["/opt/hadoop/bin/ozone","datanode"]
+      environment:
+        OZONE-SITE.XML_ozone.scm.names: scm
       env_file:
         - ./docker-config
    om:
@@ -36,6 +38,7 @@ services:
          - 9874:9874
       environment:
          ENSURE_OM_INITIALIZED: /data/metadata/om/current/VERSION
+         OZONE-SITE.XML_ozone.scm.names: scm
       env_file:
           - ./docker-config
       command: ["/opt/hadoop/bin/ozone","om"]
@@ -49,5 +52,19 @@ services:
       env_file:
           - ./docker-config
       environment:
-          ENSURE_SCM_INITIALIZED: /data/metadata/scm/current/VERSION
+        ENSURE_SCM_INITIALIZED: /data/metadata/scm/current/VERSION
+        OZONE-SITE.XML_ozone.scm.names: scm
+        OZONE-SITE.XML_ozone.om.address: om
+        OZONE-SITE.XML_ozone.om.http-address: om:9874
+        OZONE-SITE.XML_ozone.enabled: "true"
+        OZONE-SITE.XML_ozone.scm.datanode.id.dir: /data
+        OZONE-SITE.XML_ozone.scm.block.client.address: scm
+        OZONE-SITE.XML_ozone.metadata.dirs: /data/metadata
+        OZONE-SITE.XML_ozone.handler.type: distributed
+        OZONE-SITE.XML_ozone.scm.client.address: scm
+        OZONE-SITE.XML_ozone.replication: 1
+        OZONE-SITE.XML_hdds.datanode.dir: /data/hdds
+        OZONE-SITE.XML_hdds.profiler.endpoint.enabled: "true"
+        HDFS-SITE.XML_rpc.metrics.quantile.enable: "true"
+        HDFS-SITE.XML_rpc.metrics.percentiles.intervals: 60,300
       command: ["/opt/hadoop/bin/ozone","scm"]

hadoop-ozone/dist/src/main/compose/ozone/docker-config

@@ -14,20 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-OZONE-SITE.XML_ozone.om.address=om
-OZONE-SITE.XML_ozone.om.http-address=om:9874
-OZONE-SITE.XML_ozone.scm.names=scm
-OZONE-SITE.XML_ozone.enabled=True
-OZONE-SITE.XML_ozone.scm.datanode.id.dir=/data
-OZONE-SITE.XML_ozone.scm.block.client.address=scm
-OZONE-SITE.XML_ozone.metadata.dirs=/data/metadata
-OZONE-SITE.XML_ozone.handler.type=distributed
-OZONE-SITE.XML_ozone.scm.client.address=scm
-OZONE-SITE.XML_ozone.replication=1
-OZONE-SITE.XML_hdds.datanode.dir=/data/hdds
-OZONE-SITE.XML_hdds.profiler.endpoint.enabled=true
-HDFS-SITE.XML_rpc.metrics.quantile.enable=true
-HDFS-SITE.XML_rpc.metrics.percentiles.intervals=60,300
+
 ASYNC_PROFILER_HOME=/opt/profiler
 LOG4J.PROPERTIES_log4j.rootLogger=INFO, stdout
 LOG4J.PROPERTIES_log4j.appender.stdout=org.apache.log4j.ConsoleAppender

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OzoneManagerStarter.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.ozone.om;
 import org.apache.hadoop.hdds.cli.GenericCli;
 import org.apache.hadoop.hdds.cli.HddsVersionProvider;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.discovery.DiscoveryUtil;
 import org.apache.hadoop.hdds.tracing.TracingUtil;
 import org.apache.hadoop.security.authentication.client.AuthenticationException;
 import org.apache.hadoop.util.StringUtils;
@@ -100,6 +101,10 @@ public class OzoneManagerStarter extends GenericCli {
    */
   private void commonInit() {
     conf = createOzoneConfiguration();
+    if (DiscoveryUtil.loadGlobalConfig(conf)) {
+      //reload the configuration with the downloaded new configs.
+      conf = createOzoneConfiguration();
+    }
 
     String[] originalArgs = getCmd().getParseResult().originalArgs()
         .toArray(new String[0]);

hadoop-ozone/ozonefs/pom.xml

@@ -130,6 +130,12 @@
     <dependency>
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-ozone-common</artifactId>
+      <exclusions>
+        <exclusion>
+          <groupId>org.apache.hadoop</groupId>
+          <artifactId>hadoop-hdds-server-scm</artifactId>
+        </exclusion>
+      </exclusions>
     </dependency>
     <dependency>
       <groupId>org.apache.hadoop</groupId>

hadoop-ozone/s3gateway/src/main/java/org/apache/hadoop/ozone/s3/Gateway.java

@@ -22,6 +22,7 @@ import java.io.IOException;
 import org.apache.hadoop.hdds.cli.GenericCli;
 import org.apache.hadoop.hdds.cli.HddsVersionProvider;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.discovery.DiscoveryUtil;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -47,6 +48,10 @@ public class Gateway extends GenericCli {
   @Override
   public Void call() throws Exception {
     OzoneConfiguration ozoneConfiguration = createOzoneConfiguration();
+    if (DiscoveryUtil.loadGlobalConfig(ozoneConfiguration)) {
+      //reload the configuration with the downloaded new configs.
+      ozoneConfiguration = createOzoneConfiguration();
+    }
     OzoneConfigurationHolder.setConfiguration(ozoneConfiguration);
     httpServer = new S3GatewayHttpServer(ozoneConfiguration, "s3gateway");
     start();