apache · clintropolis · Aug 27, 2022 · Aug 22, 2022 · Aug 23, 2022 · Aug 23, 2022
diff --git a/docs/configuration/index.md b/docs/configuration/index.md
@@ -151,23 +151,6 @@ The following path is used for service discovery. It is **not** affected by `dru
 |--------|-----------|-------|
 |`druid.discovery.curator.path`|Services announce themselves under this ZooKeeper path.|`/druid/discovery`|
 
-### Exhibitor
-
-[Exhibitor](https://github.com/Netflix/exhibitor/wiki) is a supervisor system for ZooKeeper.
-Exhibitor can dynamically scale-up/down the cluster of ZooKeeper servers.
-Druid can update self-owned list of ZooKeeper servers through Exhibitor without restarting.
-That is, it allows Druid to keep the connections of Exhibitor-supervised ZooKeeper servers.
-
-|Property|Description|Default|
-|--------|-----------|-------|
-|`druid.exhibitor.service.hosts`|A JSON array which contains the hostnames of Exhibitor instances. Please specify this property if you want to use Exhibitor-supervised cluster.|none|
-|`druid.exhibitor.service.port`|The REST port used to connect to Exhibitor.|`8080`|
-|`druid.exhibitor.service.restUriPath`|The path of the REST call used to get the server set.|`/exhibitor/v1/cluster/list`|
-|`druid.exhibitor.service.useSsl`|Boolean flag for whether or not to use https protocol.|`false`|
-|`druid.exhibitor.service.pollingMs`|How often to poll the exhibitors for the list|`10000`|
-
-Note that `druid.zk.service.host` is used as a backup in case an Exhibitor instance can't be contacted and therefore should still be set.
-
 ### TLS
 
 #### General Configuration

diff --git a/integration-tests-ex/cases/pom.xml b/integration-tests-ex/cases/pom.xml
@@ -91,10 +91,6 @@
             <groupId>org.apache.curator</groupId>
             <artifactId>curator-framework</artifactId>
         </dependency>
-        <dependency>
-            <groupId>org.apache.curator</groupId>
-            <artifactId>curator-client</artifactId>
-        </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>

diff --git a/...ration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/cluster/ZooKeeperClient.java b/...ration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/cluster/ZooKeeperClient.java
@@ -19,11 +19,9 @@
 
 package org.apache.druid.testsEx.cluster;
 
-import org.apache.curator.ensemble.EnsembleProvider;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.druid.curator.CuratorConfig;
 import org.apache.druid.curator.CuratorModule;
-import org.apache.druid.curator.ExhibitorConfig;
 import org.apache.druid.java.util.common.ISE;
 import org.apache.druid.testsEx.config.ResolvedConfig;
 import org.apache.druid.testsEx.config.ResolvedService.ResolvedZk;
@@ -56,9 +54,7 @@ public ZooKeeperClient(ResolvedConfig config)
   private void prepare()
   {
     CuratorConfig curatorConfig = clusterConfig.toCuratorConfig();
-    ExhibitorConfig exhibitorConfig = clusterConfig.toExhibitorConfig();
-    EnsembleProvider ensembleProvider = CuratorModule.createEnsembleProvider(curatorConfig, exhibitorConfig);
-    curatorFramework = CuratorModule.createCurator(curatorConfig, ensembleProvider);
+    curatorFramework = CuratorModule.createCurator(curatorConfig);
   }
 
   private void awaitReady()

diff --git a/integration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/config/ResolvedConfig.java b/integration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/config/ResolvedConfig.java
@@ -22,7 +22,6 @@
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableMap;
 import org.apache.druid.curator.CuratorConfig;
-import org.apache.druid.curator.ExhibitorConfig;
 import org.apache.druid.java.util.common.IAE;
 import org.apache.druid.java.util.common.ISE;
 import org.apache.druid.testing.IntegrationTestingConfigProvider;
@@ -37,7 +36,6 @@
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -274,12 +272,6 @@ public CuratorConfig toCuratorConfig()
     return CuratorConfig.create(zk.clientHosts());
   }
 
-  public ExhibitorConfig toExhibitorConfig()
-  {
-    // Does not yet support exhibitors
-    return ExhibitorConfig.create(Collections.emptyList());
-  }
-
   /**
    * Map from old-style config file (and settings) name to the
    * corresponding property.

diff --git a/licenses.yaml b/licenses.yaml
@@ -1662,7 +1662,7 @@ name: Apache Curator
 license_category: binary
 module: java-core
 license_name: Apache License version 2.0
-version: 4.3.0
+version: 5.3.0
 libraries:
   - org.apache.curator: curator-client
   - org.apache.curator: curator-framework
@@ -1671,16 +1671,16 @@ libraries:
 notices:
   - curator-client: |
       Curator Client
-      Copyright 2011-2018 The Apache Software Foundation
+      Copyright 2011-2022 The Apache Software Foundation
   - curator-framework: |
       Curator Framework
-      Copyright 2011-2018 The Apache Software Foundation
+      Copyright 2011-2022 The Apache Software Foundation
   - curator-recipes: |
       Curator Recipes
-      Copyright 2011-2018 The Apache Software Foundation
+      Copyright 2011-2022 The Apache Software Foundation
   - curator-x-discovery: |
       Curator Service Discovery
-      Copyright 2011-2018 The Apache Software Foundation
+      Copyright 2011-2022 The Apache Software Foundation
 
 ---
 

diff --git a/pom.xml b/pom.xml
@@ -75,7 +75,7 @@
         <java.version>8</java.version>
         <project.build.resourceEncoding>UTF-8</project.build.resourceEncoding>
         <aether.version>0.9.0.M2</aether.version>
-        <apache.curator.version>4.3.0</apache.curator.version>
+        <apache.curator.version>5.3.0</apache.curator.version>
         <apache.kafka.version>3.2.0</apache.kafka.version>
         <apache.ranger.version>2.0.0</apache.ranger.version>
         <apache.ranger.gson.version>2.2.4</apache.ranger.gson.version>
@@ -348,34 +348,42 @@
                 <groupId>org.apache.curator</groupId>
                 <artifactId>curator-client</artifactId>
                 <version>${apache.curator.version}</version>
+                <exclusions>
+                    <exclusion>
+                        <groupId>org.slf4j</groupId>
+                        <artifactId>slf4j-api</artifactId>
+                    </exclusion>
+                    <exclusion>
+                        <groupId>com.google.guava</groupId>
+                        <artifactId>guava</artifactId>
+                    </exclusion>
+                    <exclusion>
+                        <groupId>org.apache.zookeeper</groupId>
+                        <artifactId>zookeeper</artifactId>
+                    </exclusion>
+                </exclusions>
             </dependency>
             <dependency>
                 <groupId>org.apache.curator</groupId>
                 <artifactId>curator-framework</artifactId>
                 <version>${apache.curator.version}</version>
-                <exclusions>
-                    <exclusion>
-                        <groupId>org.jboss.netty</groupId>
-                        <artifactId>netty</artifactId>
-                    </exclusion>
-                </exclusions>
             </dependency>
             <dependency>
                 <groupId>org.apache.curator</groupId>
                 <artifactId>curator-recipes</artifactId>
                 <version>${apache.curator.version}</version>
+            </dependency>
+            <dependency>
+                <groupId>org.apache.curator</groupId>
+                <artifactId>curator-x-discovery</artifactId>
+                <version>${apache.curator.version}</version>
                 <exclusions>
                     <exclusion>
-                        <groupId>org.apache.zookeeper</groupId>
-                        <artifactId>zookeeper</artifactId>
+                        <groupId>com.fasterxml.jackson.core</groupId>
+                        <artifactId>jackson-databind</artifactId>
                     </exclusion>
                 </exclusions>
             </dependency>
-            <dependency>
-              <groupId>org.apache.curator</groupId>
-              <artifactId>curator-x-discovery</artifactId>
-              <version>${apache.curator.version}</version>
-            </dependency>
             <dependency>
                 <groupId>org.apache.calcite</groupId>
                 <artifactId>calcite-core</artifactId>
@@ -986,8 +994,8 @@
                 <version>${apache.curator.version}</version>
                 <exclusions>
                     <exclusion>
-                        <groupId>org.jboss.netty</groupId>
-                        <artifactId>netty</artifactId>
+                        <groupId>org.junit.jupiter</groupId>
+                        <artifactId>junit-jupiter-api</artifactId>
                     </exclusion>
                 </exclusions>
                 <scope>test</scope>

diff --git a/server/src/main/java/org/apache/druid/curator/CuratorModule.java b/server/src/main/java/org/apache/druid/curator/CuratorModule.java
@@ -23,10 +23,6 @@
 import com.google.inject.Module;
 import com.google.inject.Provides;
 import org.apache.curator.RetryPolicy;
-import org.apache.curator.ensemble.EnsembleProvider;
-import org.apache.curator.ensemble.exhibitor.DefaultExhibitorRestClient;
-import org.apache.curator.ensemble.exhibitor.ExhibitorEnsembleProvider;
-import org.apache.curator.ensemble.exhibitor.Exhibitors;
 import org.apache.curator.ensemble.fixed.FixedEnsembleProvider;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
@@ -49,23 +45,22 @@ public class CuratorModule implements Module
 {
   private static final Logger log = new Logger(CuratorModule.class);
 
-  private static final int BASE_SLEEP_TIME_MS = 1000;
-  private static final int MAX_SLEEP_TIME_MS = 45000;
+  static final int BASE_SLEEP_TIME_MS = 1000;
+  static final int MAX_SLEEP_TIME_MS = 45000;
   private static final int MAX_RETRIES = 29;
 
   @Override
   public void configure(Binder binder)
   {
     JsonConfigProvider.bind(binder, CuratorConfig.CONFIG_PREFIX, ZkEnablementConfig.class);
     JsonConfigProvider.bind(binder, CuratorConfig.CONFIG_PREFIX, CuratorConfig.class);
-    JsonConfigProvider.bind(binder, ExhibitorConfig.CONFIG_PREFIX, ExhibitorConfig.class);
   }
 
   /**
    * Create the Curator framework outside of Guice given the ZK config.
    * Primarily for tests.
    */
-  public static CuratorFramework createCurator(CuratorConfig config, EnsembleProvider ensembleProvider)
+  public static CuratorFramework createCurator(CuratorConfig config)
   {
     final CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder();
     if (!Strings.isNullOrEmpty(config.getZkUser()) && !Strings.isNullOrEmpty(config.getZkPwd())) {
@@ -78,7 +73,7 @@ public static CuratorFramework createCurator(CuratorConfig config, EnsembleProvi
     RetryPolicy retryPolicy = new BoundedExponentialBackoffRetry(BASE_SLEEP_TIME_MS, MAX_SLEEP_TIME_MS, MAX_RETRIES);
 
     return builder
-        .ensembleProvider(ensembleProvider)
+        .ensembleProvider(new FixedEnsembleProvider(config.getZkHosts()))
         .sessionTimeoutMs(config.getZkSessionTimeoutMs())
         .connectionTimeoutMs(config.getZkConnectionTimeoutMs())
         .retryPolicy(retryPolicy)
@@ -92,13 +87,13 @@ public static CuratorFramework createCurator(CuratorConfig config, EnsembleProvi
    */
   @Provides
   @LazySingleton
-  public CuratorFramework makeCurator(ZkEnablementConfig zkEnablementConfig, CuratorConfig config, EnsembleProvider ensembleProvider, Lifecycle lifecycle)
+  public CuratorFramework makeCurator(ZkEnablementConfig zkEnablementConfig, CuratorConfig config, Lifecycle lifecycle)
   {
     if (!zkEnablementConfig.isEnabled()) {
       throw new RuntimeException("Zookeeper is disabled, cannot create CuratorFramework.");
     }
 
-    final CuratorFramework framework = createCurator(config, ensembleProvider);
+    final CuratorFramework framework = createCurator(config);
 
     framework.getUnhandledErrorListenable().addListener((message, e) -> {
       log.error(e, "Unhandled error in Curator, stopping server.");
@@ -127,55 +122,6 @@ public void stop()
     return framework;
   }
 
-  /**
-   * Create an EnsembleProvider given the related configurations. Primarily for tests
-   * which do not use Guice to do the work.
-   */
-  public static EnsembleProvider createEnsembleProvider(CuratorConfig config, ExhibitorConfig exConfig)
-  {
-    if (exConfig.getHosts().isEmpty()) {
-      return new FixedEnsembleProvider(config.getZkHosts());
-    }
-
-    RetryPolicy retryPolicy = new BoundedExponentialBackoffRetry(BASE_SLEEP_TIME_MS, MAX_SLEEP_TIME_MS, MAX_RETRIES);
-
-    return new ExhibitorEnsembleProvider(
-        new Exhibitors(
-            exConfig.getHosts(),
-            exConfig.getRestPort(),
-            newBackupProvider(config.getZkHosts())
-        ),
-        new DefaultExhibitorRestClient(exConfig.getUseSsl()),
-        exConfig.getRestUriPath(),
-        exConfig.getPollingMs(),
-        retryPolicy
-    )
-    {
-      @Override
-      public void start() throws Exception
-      {
-        log.debug("Polling the list of ZooKeeper servers for the initial ensemble");
-        this.pollForInitialEnsemble();
-        super.start();
-      }
-    };
-  }
-
-  /**
-   * Provide an EnsembleProvider via Guice configuration.
-   */
-  @Provides
-  @LazySingleton
-  public EnsembleProvider makeEnsembleProvider(CuratorConfig config, ExhibitorConfig exConfig)
-  {
-    return createEnsembleProvider(config, exConfig);
-  }
-
-  private static Exhibitors.BackupConnectionStringProvider newBackupProvider(final String zkHosts)
-  {
-    return () -> zkHosts;
-  }
-
   static class SecuredACLProvider implements ACLProvider
   {
     @Override

diff --git a/server/src/main/java/org/apache/druid/curator/ExhibitorConfig.java b/server/src/main/java/org/apache/druid/curator/ExhibitorConfig.java