[Placement Group] Add get / get all / remove interface for Placement Group Java api. (#11821)

* add placement group java get/get all interface

* add remove placement group api

* fix some issue like: Placement Group -> placement group

* extract dumplicate code to placement group utils

* specify running mode for placement group ut

* update checkGlobalStateAccessorPointerValid -> validateGlobalStateAccessorPointer

* use THROW_EXCEPTION_AND_RETURN_IF_NOT_OK

* update pg log print

java/api/src/main/java/io/ray/api/Ray.java

@@ -1,5 +1,6 @@
 package io.ray.api;
 
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.UniqueId;
 import io.ray.api.placementgroup.PlacementGroup;
 import io.ray.api.placementgroup.PlacementStrategy;
@@ -245,7 +246,7 @@ public final class Ray extends RayCall {
    * to be updated and rescheduled.
    * This function only works when gcs actor manager is turned on.
    *
-   * @param name Name of the Placement Group.
+   * @param name Name of the placement group.
    * @param bundles Pre-allocated resource list.
    * @param strategy Actor placement strategy.
    * @return A handle to the created placement group.
@@ -271,4 +272,30 @@ public final class Ray extends RayCall {
   public static void exitActor() {
     runtime.exitActor();
   }
+
+  /**
+   * Get a placement group by placement group Id.
+   * @param id placement group id.
+   * @return The placement group.
+   */
+  public static PlacementGroup getPlacementGroup(PlacementGroupId id) {
+    return internal().getPlacementGroup(id);
+  }
+
+  /**
+   * Get all placement groups in this cluster.
+   * @return All placement groups.
+   */
+  public static List<PlacementGroup> getAllPlacementGroups() {
+    return internal().getAllPlacementGroups();
+  }
+
+  /**
+   * Remove a placement group by id.
+   * Throw RayException if remove failed.
+   * @param id Id of the placement group.
+   */
+  public static void removePlacementGroup(PlacementGroupId id) {
+    internal().removePlacementGroup(id);
+  }
 }

java/api/src/main/java/io/ray/api/id/PlacementGroupId.java

@@ -1,6 +1,5 @@
-package io.ray.runtime.placementgroup;
+package io.ray.api.id;
 
-import io.ray.api.id.BaseId;
 import java.io.Serializable;
 import java.nio.ByteBuffer;
 import java.util.Arrays;

java/api/src/main/java/io/ray/api/placementgroup/PlacementGroupState.java

@@ -0,0 +1,42 @@
+package io.ray.api.placementgroup;
+
+/**
+ * State of placement group.
+ */
+public enum PlacementGroupState {
+
+  /**
+   * Wait for resource to schedule.
+   */
+  PENDING(0),
+
+  /**
+   * The placement group has created on some node.
+   */
+  CREATED(1),
+
+  /**
+   * The placement group has removed.
+   */
+  REMOVED(2),
+
+  /**
+   * The placement group is rescheduling.
+   */
+  RESCHEDULING(3),
+
+  /**
+   * Unrecognized state.
+   */
+  UNRECOGNIZED(-1);
+
+  private int value = 0;
+
+  PlacementGroupState(int value) {
+    this.value = value;
+  }
+
+  public int value() {
+    return this.value;
+  }
+}

java/api/src/main/java/io/ray/api/placementgroup/PlacementStrategy.java

@@ -23,7 +23,12 @@ public enum PlacementStrategy {
    * Places Bundles across distinct nodes.
    * The group is not allowed to deploy more than one bundle on a node.
    */
-  STRICT_SPREAD(3);
+  STRICT_SPREAD(3),
+
+  /**
+   * Unrecognized strategy.
+   */
+  UNRECOGNIZED(-1);
 
   private int value = 0;
 

java/api/src/main/java/io/ray/api/runtime/RayRuntime.java

@@ -10,6 +10,7 @@ import io.ray.api.function.PyActorMethod;
 import io.ray.api.function.PyFunction;
 import io.ray.api.function.RayFunc;
 import io.ray.api.id.ActorId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.UniqueId;
 import io.ray.api.options.ActorCreationOptions;
 import io.ray.api.options.CallOptions;
@@ -202,4 +203,22 @@ public interface RayRuntime {
    */
   void exitActor();
 
+  /**
+   * Get a placement group by id.
+   * @param id placement group id.
+   * @return The placement group.
+   */
+  PlacementGroup getPlacementGroup(PlacementGroupId id);
+
+  /**
+   * Get all placement groups in this cluster.
+   * @return All placement groups.
+   */
+  List<PlacementGroup> getAllPlacementGroups();
+
+  /**
+   * Remove a placement group by id.
+   * @param id Id of the placement group.
+   */
+  void removePlacementGroup(PlacementGroupId id);
 }

java/runtime/src/main/java/io/ray/runtime/AbstractRayRuntime.java

@@ -14,6 +14,7 @@ import io.ray.api.function.PyFunction;
 import io.ray.api.function.RayFunc;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.ObjectId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.options.ActorCreationOptions;
 import io.ray.api.options.CallOptions;
 import io.ray.api.placementgroup.PlacementGroup;
@@ -184,6 +185,21 @@ public abstract class AbstractRayRuntime implements RayRuntimeInternal {
     return createPlacementGroup(DEFAULT_PLACEMENT_GROUP_NAME, bundles, strategy);
   }
 
+  @Override
+  public void removePlacementGroup(PlacementGroupId id) {
+    taskSubmitter.removePlacementGroup(id);
+  }
+
+  @Override
+  public PlacementGroup getPlacementGroup(PlacementGroupId id) {
+    return gcsClient.getPlacementGroupInfo(id);
+  }
+
+  @Override
+  public List<PlacementGroup> getAllPlacementGroups() {
+    return gcsClient.getAllPlacementGroupInfo();
+  }
+
   @SuppressWarnings("unchecked")
   @Override
   public <T extends BaseActorHandle> T getActorHandle(ActorId actorId) {

java/runtime/src/main/java/io/ray/runtime/RayDevRuntime.java

@@ -3,12 +3,15 @@ package io.ray.runtime;
 import com.google.common.base.Preconditions;
 import io.ray.api.BaseActorHandle;
 import io.ray.api.id.JobId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.UniqueId;
+import io.ray.api.placementgroup.PlacementGroup;
 import io.ray.runtime.config.RayConfig;
 import io.ray.runtime.context.LocalModeWorkerContext;
 import io.ray.runtime.object.LocalModeObjectStore;
 import io.ray.runtime.task.LocalModeTaskExecutor;
 import io.ray.runtime.task.LocalModeTaskSubmitter;
+import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.slf4j.Logger;
@@ -84,6 +87,21 @@ public class RayDevRuntime extends AbstractRayRuntime {
     super.setAsyncContext(asyncContext);
   }
 
+  @Override
+  public PlacementGroup getPlacementGroup(
+      PlacementGroupId id) {
+    //@TODO(clay4444): We need a LocalGcsClient before implements this.
+    throw new UnsupportedOperationException(
+      "Ray doesn't support placement group operations in local mode.");
+  }
+
+  @Override
+  public List<PlacementGroup> getAllPlacementGroups() {
+    //@TODO(clay4444): We need a LocalGcsClient before implements this.
+    throw new UnsupportedOperationException(
+      "Ray doesn't support placement group operations in local mode.");
+  }
+
   @Override
   public void exitActor() {
 

java/runtime/src/main/java/io/ray/runtime/gcs/GcsClient.java

@@ -6,13 +6,16 @@ import io.ray.api.Checkpointable.Checkpoint;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.BaseId;
 import io.ray.api.id.JobId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.TaskId;
 import io.ray.api.id.UniqueId;
+import io.ray.api.placementgroup.PlacementGroup;
 import io.ray.api.runtimecontext.NodeInfo;
 import io.ray.runtime.generated.Gcs;
 import io.ray.runtime.generated.Gcs.ActorCheckpointIdData;
 import io.ray.runtime.generated.Gcs.GcsNodeInfo;
 import io.ray.runtime.generated.Gcs.TablePrefix;
+import io.ray.runtime.placementgroup.PlacementGroupUtils;
 import io.ray.runtime.util.IdUtil;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -52,6 +55,30 @@ public class GcsClient {
     globalStateAccessor = GlobalStateAccessor.getInstance(redisAddress, redisPassword);
   }
 
+  /**
+   * Get placement group by {@link PlacementGroupId}
+   * @param placementGroupId Id of placement group.
+   * @return The placement group.
+   */
+  public PlacementGroup getPlacementGroupInfo(PlacementGroupId placementGroupId) {
+    byte[] result = globalStateAccessor.getPlacementGroupInfo(placementGroupId);
+    return PlacementGroupUtils.generatePlacementGroupFromByteArray(result);
+  }
+
+  /**
+   * Get all placement groups in this cluster.
+   * @return All placement groups.
+   */
+  public List<PlacementGroup> getAllPlacementGroupInfo() {
+    List<byte[]> results = globalStateAccessor.getAllPlacementGroupInfo();
+
+    List<PlacementGroup> placementGroups = new ArrayList<>();
+    for (byte[] result : results) {
+      placementGroups.add(PlacementGroupUtils.generatePlacementGroupFromByteArray(result));
+    }
+    return placementGroups;
+  }
+
   public List<NodeInfo> getAllNodeInfo() {
     List<byte[]> results = globalStateAccessor.getAllNodeInfo();
 

java/runtime/src/main/java/io/ray/runtime/gcs/GlobalStateAccessor.java

@@ -2,6 +2,7 @@ package io.ray.runtime.gcs;
 
 import com.google.common.base.Preconditions;
 import io.ray.api.id.ActorId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.UniqueId;
 import java.util.List;
 
@@ -33,8 +34,7 @@ public class GlobalStateAccessor {
   private GlobalStateAccessor(String redisAddress, String redisPassword) {
     globalStateAccessorNativePointer =
       nativeCreateGlobalStateAccessor(redisAddress, redisPassword);
-    Preconditions.checkState(globalStateAccessorNativePointer != 0,
+    validateGlobalStateAccessorPointer();
-          "Global state accessor native pointer must not be 0.");
     connect();
   }
 
@@ -42,14 +42,18 @@ public class GlobalStateAccessor {
     return this.nativeConnect(globalStateAccessorNativePointer);
   }
 
+  private void validateGlobalStateAccessorPointer() {
+    Preconditions.checkState(globalStateAccessorNativePointer != 0,
+        "Global state accessor native pointer must not be 0.");
+  }
+
   /**
    * @return A list of job info with JobInfo protobuf schema.
    */
   public List<byte[]> getAllJobInfo() {
     // Fetch a job list with protobuf bytes format from GCS.
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0,
+      validateGlobalStateAccessorPointer();
-          "Get all job info when global state accessor have been destroyed.");
       return this.nativeGetAllJobInfo(globalStateAccessorNativePointer);
     }
   }
@@ -60,8 +64,7 @@ public class GlobalStateAccessor {
   public List<byte[]> getAllNodeInfo() {
     // Fetch a node list with protobuf bytes format from GCS.
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0,
+      validateGlobalStateAccessorPointer();
-          "Get all node info when global state accessor have been destroyed.");
       return this.nativeGetAllNodeInfo(globalStateAccessorNativePointer);
     }
   }
@@ -72,16 +75,30 @@ public class GlobalStateAccessor {
    */
   public byte[] getNodeResourceInfo(UniqueId nodeId) {
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0,
+      validateGlobalStateAccessorPointer();
-          "Get resource info by node id when global state accessor have been destroyed.");
       return nativeGetNodeResourceInfo(globalStateAccessorNativePointer, nodeId.getBytes());
     }
   }
 
+  public byte[] getPlacementGroupInfo(PlacementGroupId placementGroupId) {
+    synchronized (GlobalStateAccessor.class) {
+      Preconditions.checkNotNull(placementGroupId,
+          "PlacementGroupId can't be null when get placement group info.");
+      return nativeGetPlacementGroupInfo(globalStateAccessorNativePointer,
+        placementGroupId.getBytes());
+    }
+  }
+
+  public List<byte[]> getAllPlacementGroupInfo() {
+    synchronized (GlobalStateAccessor.class) {
+      validateGlobalStateAccessorPointer();
+      return this.nativeGetAllPlacementGroupInfo(globalStateAccessorNativePointer);
+    }
+  }
+
   public byte[] getInternalConfig() {
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0,
+      validateGlobalStateAccessorPointer();
-          "Get internal config when global state accessor have been destroyed.");
       return nativeGetInternalConfig(globalStateAccessorNativePointer);
     }
   }
@@ -92,7 +109,7 @@ public class GlobalStateAccessor {
   public List<byte[]> getAllActorInfo() {
     // Fetch a actor list with protobuf bytes format from GCS.
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0);
+      validateGlobalStateAccessorPointer();
       return this.nativeGetAllActorInfo(globalStateAccessorNativePointer);
     }
   }
@@ -103,7 +120,7 @@ public class GlobalStateAccessor {
   public byte[] getActorInfo(ActorId actorId) {
     // Fetch an actor with protobuf bytes format from GCS.
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0);
+      validateGlobalStateAccessorPointer();
       return this.nativeGetActorInfo(globalStateAccessorNativePointer, actorId.getBytes());
     }
   }
@@ -114,7 +131,7 @@ public class GlobalStateAccessor {
   public byte[] getActorCheckpointId(ActorId actorId) {
     // Fetch an actor checkpoint id with protobuf bytes format from GCS.
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0);
+      validateGlobalStateAccessorPointer();
       return this.nativeGetActorCheckpointId(globalStateAccessorNativePointer, actorId.getBytes());
     }
   }
@@ -148,4 +165,9 @@ public class GlobalStateAccessor {
   private native byte[] nativeGetActorInfo(long nativePtr, byte[] actorId);
 
   private native byte[] nativeGetActorCheckpointId(long nativePtr, byte[] actorId);
+
+  private native byte[] nativeGetPlacementGroupInfo(long nativePtr,
+      byte[] placementGroupId);
+
+  private native List<byte[]> nativeGetAllPlacementGroupInfo(long nativePtr);
 }

java/runtime/src/main/java/io/ray/runtime/placementgroup/PlacementGroupImpl.java

@@ -1,6 +1,8 @@
 package io.ray.runtime.placementgroup;
 
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.placementgroup.PlacementGroup;
+import io.ray.api.placementgroup.PlacementGroupState;
 import io.ray.api.placementgroup.PlacementStrategy;
 import java.util.List;
 import java.util.Map;
@@ -48,7 +50,7 @@ public class PlacementGroupImpl implements PlacementGroup {
   }
 
   /**
-   * A help class for create the Placement Group.
+   * A help class for create the placement group.
    */
   public static class Builder {
     private PlacementGroupId id;
@@ -58,8 +60,8 @@ public class PlacementGroupImpl implements PlacementGroup {
     private PlacementGroupState state;
 
     /**
-     * Set the Id of the Placement Group.
+     * Set the Id of the placement group.
-     * @param id Id of the Placement Group.
+     * @param id Id of the placement group.
      * @return self.
      */
     public Builder setId(PlacementGroupId id) {
@@ -68,8 +70,8 @@ public class PlacementGroupImpl implements PlacementGroup {
     }
 
     /**
-     * Set the name of the Placement Group.
+     * Set the name of the placement group.
-     * @param name Name of the Placement Group.
+     * @param name Name of the placement group.
      * @return self.
      */
     public Builder setName(String name) {
@@ -78,8 +80,8 @@ public class PlacementGroupImpl implements PlacementGroup {
     }
 
     /**
-     * Set the bundles of the Placement Group.
+     * Set the bundles of the placement group.
-     * @param bundles the bundles of the Placement Group.
+     * @param bundles the bundles of the placement group.
      * @return self.
      */
     public Builder setBundles(List<Map<String, Double>> bundles) {
@@ -88,8 +90,8 @@ public class PlacementGroupImpl implements PlacementGroup {
     }
 
     /**
-     * Set the placement strategy of the Placement Group.
+     * Set the placement strategy of the placement group.
-     * @param strategy the placement strategy of the Placement Group.
+     * @param strategy the placement strategy of the placement group.
      * @return self.
      */
     public Builder setStrategy(PlacementStrategy strategy) {
@@ -98,8 +100,8 @@ public class PlacementGroupImpl implements PlacementGroup {
     }
 
     /**
-     * Set the placement state of the Placement Group.
+     * Set the placement state of the placement group.
-     * @param state the state of the Placement Group.
+     * @param state the state of the placement group.
      * @return self.
      */
     public Builder setState(PlacementGroupState state) {

java/runtime/src/main/java/io/ray/runtime/placementgroup/PlacementGroupState.java

@@ -1,32 +0,0 @@
-package io.ray.runtime.placementgroup;
-
-/**
- * State of Placement Group.
- */
-public enum PlacementGroupState {
-
-  /**
-   * Wait for resource to schedule.
-   */
-  PENDING(0),
-
-  /**
-   * The Placement Group has created on some node.
-   */
-  CREATED(1),
-
-  /**
-   * The Placement Group has removed.
-   */
-  REMOVED(2);
-
-  private int value = 0;
-
-  PlacementGroupState(int value) {
-    this.value = value;
-  }
-
-  public int value() {
-    return this.value;
-  }
-}

java/runtime/src/main/java/io/ray/runtime/placementgroup/PlacementGroupUtils.java

@@ -0,0 +1,108 @@
+package io.ray.runtime.placementgroup;
+
+import com.google.common.base.Preconditions;
+import com.google.protobuf.InvalidProtocolBufferException;
+import io.ray.api.id.PlacementGroupId;
+import io.ray.api.placementgroup.PlacementGroupState;
+import io.ray.api.placementgroup.PlacementStrategy;
+import io.ray.runtime.generated.Common;
+import io.ray.runtime.generated.Common.Bundle;
+import io.ray.runtime.generated.Gcs.PlacementGroupTableData;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Utils for placement group.
+ */
+public class PlacementGroupUtils {
+
+  private static List<Map<String, Double>> covertToUserSpecifiedBundles(List<Bundle> bundles) {
+    List<Map<String, Double>> result = new ArrayList<>();
+
+    // NOTE(clay4444): We need to guarantee the order here.
+    for (int i = 0; i < bundles.size(); i++) {
+      Bundle bundle = bundles.get(i);
+      result.add(bundle.getUnitResourcesMap());
+    }
+    return result;
+  }
+
+  private static PlacementStrategy covertToUserSpecifiedStrategy(
+      Common.PlacementStrategy strategy) {
+    switch (strategy) {
+      case PACK:
+        return PlacementStrategy.PACK;
+      case STRICT_PACK:
+        return PlacementStrategy.STRICT_PACK;
+      case SPREAD:
+        return PlacementStrategy.SPREAD;
+      case STRICT_SPREAD:
+        return PlacementStrategy.STRICT_SPREAD;
+      default:
+        return PlacementStrategy.UNRECOGNIZED;
+    }
+  }
+
+  private static PlacementGroupState covertToUserSpecifiedState(
+      PlacementGroupTableData.PlacementGroupState state) {
+    switch (state) {
+      case PENDING:
+        return PlacementGroupState.PENDING;
+      case CREATED:
+        return PlacementGroupState.CREATED;
+      case REMOVED:
+        return PlacementGroupState.REMOVED;
+      case RESCHEDULING:
+        return PlacementGroupState.RESCHEDULING;
+      default:
+        return PlacementGroupState.UNRECOGNIZED;
+    }
+  }
+
+  /**
+   * Generate a PlacementGroupImpl from placementGroupTableData protobuf data.
+   * @param placementGroupTableData protobuf data.
+   * @return placement group info {@link PlacementGroupImpl}
+   */
+  private static PlacementGroupImpl generatePlacementGroupFromPbData(
+      PlacementGroupTableData placementGroupTableData) {
+
+    PlacementGroupState state = covertToUserSpecifiedState(
+        placementGroupTableData.getState());
+    PlacementStrategy strategy = covertToUserSpecifiedStrategy(
+        placementGroupTableData.getStrategy());
+
+    List<Map<String, Double>> bundles = covertToUserSpecifiedBundles(
+        placementGroupTableData.getBundlesList());
+
+    PlacementGroupId placementGroupId = PlacementGroupId.fromByteBuffer(
+        placementGroupTableData.getPlacementGroupId().asReadOnlyByteBuffer());
+
+    return new PlacementGroupImpl.Builder()
+      .setId(placementGroupId).setName(placementGroupTableData.getName())
+      .setState(state).setStrategy(strategy).setBundles(bundles)
+      .build();
+  }
+
+  /**
+   * Generate a PlacementGroupImpl from byte array.
+   * @param placementGroupByteArray bytes array from native method.
+   * @return placement group info {@link PlacementGroupImpl}
+   */
+  public static PlacementGroupImpl generatePlacementGroupFromByteArray(
+      byte[] placementGroupByteArray) {
+    Preconditions.checkNotNull(placementGroupByteArray,
+        "Can't generate a placement group from empty byte array.");
+
+    PlacementGroupTableData placementGroupTableData;
+    try {
+      placementGroupTableData = PlacementGroupTableData.parseFrom(placementGroupByteArray);
+    } catch (InvalidProtocolBufferException e) {
+      throw new RuntimeException(
+        "Received invalid placement group table protobuf data from GCS.", e);
+    }
+
+    return generatePlacementGroupFromPbData(placementGroupTableData);
+  }
+}

java/runtime/src/main/java/io/ray/runtime/task/LocalModeTaskSubmitter.java

@@ -8,6 +8,7 @@ import io.ray.api.BaseActorHandle;
 import io.ray.api.Ray;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.ObjectId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.id.TaskId;
 import io.ray.api.id.UniqueId;
 import io.ray.api.options.ActorCreationOptions;
@@ -75,6 +76,8 @@ public class LocalModeTaskSubmitter implements TaskSubmitter {
 
   private final Map<ActorId, TaskExecutor.ActorContext> actorContexts = new ConcurrentHashMap<>();
 
+  private final Map<PlacementGroupId, PlacementGroup> placementGroups = new ConcurrentHashMap<>();
+
   public LocalModeTaskSubmitter(RayRuntimeInternal runtime, TaskExecutor taskExecutor,
                                 LocalModeObjectStore objectStore) {
     this.runtime = runtime;
@@ -225,8 +228,16 @@ public class LocalModeTaskSubmitter implements TaskSubmitter {
   @Override
   public PlacementGroup createPlacementGroup(String name, List<Map<String, Double>> bundles,
       PlacementStrategy strategy) {
-    return new PlacementGroupImpl.Builder()
+    PlacementGroupImpl placementGroup = new PlacementGroupImpl.Builder()
-      .setName(name).setBundles(bundles).setStrategy(strategy).build();
+        .setId(PlacementGroupId.fromRandom()).setName(name)
+        .setBundles(bundles).setStrategy(strategy).build();
+    placementGroups.put(placementGroup.getId(), placementGroup);
+    return placementGroup;
+  }
+
+  @Override
+  public void removePlacementGroup(PlacementGroupId id) {
+    placementGroups.remove(id);
   }
 
   @Override

java/runtime/src/main/java/io/ray/runtime/task/NativeTaskSubmitter.java

@@ -6,13 +6,13 @@ import io.ray.api.BaseActorHandle;
 import io.ray.api.Ray;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.ObjectId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.options.ActorCreationOptions;
 import io.ray.api.options.CallOptions;
 import io.ray.api.placementgroup.PlacementGroup;
 import io.ray.api.placementgroup.PlacementStrategy;
 import io.ray.runtime.actor.NativeActorHandle;
 import io.ray.runtime.functionmanager.FunctionDescriptor;
-import io.ray.runtime.placementgroup.PlacementGroupId;
 import io.ray.runtime.placementgroup.PlacementGroupImpl;
 import java.util.List;
 import java.util.Map;
@@ -86,6 +86,11 @@ public class NativeTaskSubmitter implements TaskSubmitter {
       .setName(name).setBundles(bundles).setStrategy(strategy).build();
   }
 
+  @Override
+  public void removePlacementGroup(PlacementGroupId id) {
+    nativeRemovePlacementGroup(id.getBytes());
+  }
+
   private static native List<byte[]> nativeSubmitTask(FunctionDescriptor functionDescriptor,
       int functionDescriptorHash, List<FunctionArg> args, int numReturns, CallOptions callOptions);
 
@@ -99,4 +104,7 @@ public class NativeTaskSubmitter implements TaskSubmitter {
 
   private static native byte[] nativeCreatePlacementGroup(String name,
       List<Map<String, Double>> bundles, int strategy);
+
+  private static native void nativeRemovePlacementGroup(byte[] placementGroupId);
+
 }

java/runtime/src/main/java/io/ray/runtime/task/TaskSubmitter.java

@@ -3,6 +3,7 @@ package io.ray.runtime.task;
 import io.ray.api.BaseActorHandle;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.ObjectId;
+import io.ray.api.id.PlacementGroupId;
 import io.ray.api.options.ActorCreationOptions;
 import io.ray.api.options.CallOptions;
 import io.ray.api.placementgroup.PlacementGroup;
@@ -53,7 +54,7 @@ public interface TaskSubmitter {
   /**
    * Create a placement group.
    *
-   * @param name Name of the Placement Group.
+   * @param name Name of the placement group.
    * @param bundles Pre-allocated resource list.
    * @param strategy Actor placement strategy.
    * @return A handle to the created placement group.
@@ -61,6 +62,12 @@ public interface TaskSubmitter {
   PlacementGroup createPlacementGroup(String name, List<Map<String, Double>> bundles,
       PlacementStrategy strategy);
 
+  /**
+   * Remove a placement group by id.
+   * @param id Id of the placement group.
+   */
+  void removePlacementGroup(PlacementGroupId id);
+
   BaseActorHandle getActor(ActorId actorId);
 
 }

java/test/src/main/java/io/ray/test/PlacementGroupTest.java

@@ -4,7 +4,10 @@ import io.ray.api.ActorHandle;
 import io.ray.api.Ray;
 import io.ray.api.id.ActorId;
 import io.ray.api.placementgroup.PlacementGroup;
+import io.ray.api.placementgroup.PlacementGroupState;
+import io.ray.api.placementgroup.PlacementStrategy;
 import io.ray.runtime.placementgroup.PlacementGroupImpl;
+import java.util.List;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
@@ -40,6 +43,62 @@ public class PlacementGroupTest extends BaseTest {
     Assert.assertEquals(Integer.valueOf(1), actor.task(Counter::getValue).remote().get());
   }
 
+  @Test(groups = {"cluster"})
+  public void testGetPlacementGroup() {
+    PlacementGroupImpl firstPlacementGroup = (PlacementGroupImpl)PlacementGroupTestUtils
+        .createNameSpecifiedSimpleGroup("CPU", 1, PlacementStrategy.PACK,
+        1.0, "first_placement_group");
+
+    PlacementGroupImpl secondPlacementGroup = (PlacementGroupImpl)PlacementGroupTestUtils
+        .createNameSpecifiedSimpleGroup("CPU", 1, PlacementStrategy.PACK,
+        1.0, "second_placement_group");
+
+    PlacementGroupImpl firstPlacementGroupRes =
+        (PlacementGroupImpl)Ray.getPlacementGroup((firstPlacementGroup).getId());
+    PlacementGroupImpl secondPlacementGroupRes =
+        (PlacementGroupImpl)Ray.getPlacementGroup((secondPlacementGroup).getId());
+
+    Assert.assertNotNull(firstPlacementGroupRes);
+    Assert.assertNotNull(secondPlacementGroupRes);
+
+    Assert.assertEquals(firstPlacementGroup.getId(), firstPlacementGroupRes.getId());
+    Assert.assertEquals(firstPlacementGroup.getName(), firstPlacementGroupRes.getName());
+    Assert.assertEquals(firstPlacementGroupRes.getBundles().size(), 1);
+    Assert.assertEquals(firstPlacementGroupRes.getStrategy(), PlacementStrategy.PACK);
+
+    List<PlacementGroup> allPlacementGroup = Ray.getAllPlacementGroups();
+    Assert.assertEquals(allPlacementGroup.size(), 2);
+
+    PlacementGroupImpl placementGroupRes = (PlacementGroupImpl)allPlacementGroup.get(0);
+    Assert.assertNotNull(placementGroupRes.getId());
+    PlacementGroupImpl expectPlacementGroup = placementGroupRes.getId()
+        .equals(firstPlacementGroup.getId()) ? firstPlacementGroup : secondPlacementGroup;
+
+    Assert.assertEquals(placementGroupRes.getName(), expectPlacementGroup.getName());
+    Assert.assertEquals(placementGroupRes.getBundles().size(),
+        expectPlacementGroup.getBundles().size());
+    Assert.assertEquals(placementGroupRes.getStrategy(), expectPlacementGroup.getStrategy());
+  }
+
+  @Test(groups = {"cluster"})
+  public void testRemovePlacementGroup() {
+    PlacementGroupTestUtils.createNameSpecifiedSimpleGroup("CPU",
+        1, PlacementStrategy.PACK, 1.0, "first_placement_group");
+
+    PlacementGroupImpl secondPlacementGroup = (PlacementGroupImpl)PlacementGroupTestUtils
+        .createNameSpecifiedSimpleGroup("CPU", 1, PlacementStrategy.PACK,
+        1.0, "second_placement_group");
+
+    List<PlacementGroup> allPlacementGroup = Ray.getAllPlacementGroups();
+    Assert.assertEquals(allPlacementGroup.size(), 2);
+
+    Ray.removePlacementGroup(secondPlacementGroup.getId());
+
+    PlacementGroupImpl removedPlacementGroup =
+        (PlacementGroupImpl)Ray.getPlacementGroup((secondPlacementGroup).getId());
+    Assert.assertEquals(removedPlacementGroup.getState(), PlacementGroupState.REMOVED);
+  }
+
   public void testCheckBundleIndex() {
     PlacementGroup placementGroup = PlacementGroupTestUtils.createSimpleGroup();
 

java/test/src/main/java/io/ray/test/PlacementGroupTestUtils.java

@@ -9,12 +9,12 @@ import java.util.List;
 import java.util.Map;
 
 /**
- * A utils class for Placement Group test.
+ * A utils class for placement group test.
  */
 public class PlacementGroupTestUtils {
 
-  public static PlacementGroup createSpecifiedSimpleGroup(String resourceName, int bundleSize,
+  public static PlacementGroup createNameSpecifiedSimpleGroup(String resourceName, int bundleSize,
-      PlacementStrategy strategy, Double resourceSize) {
+      PlacementStrategy strategy, Double resourceSize, String groupName) {
     List<Map<String, Double>> bundles = new ArrayList<>();
 
     for (int i = 0; i < bundleSize; i++) {
@@ -23,7 +23,13 @@ public class PlacementGroupTestUtils {
       bundles.add(bundle);
     }
 
-    return Ray.createPlacementGroup(bundles, strategy);
+    return Ray.createPlacementGroup(groupName, bundles, strategy);
+  }
+
+  public static PlacementGroup createSpecifiedSimpleGroup(String resourceName, int bundleSize,
+      PlacementStrategy strategy, Double resourceSize) {
+    return createNameSpecifiedSimpleGroup(resourceName, bundleSize, strategy,
+      resourceSize, "unnamed_group");
   }
 
   public static PlacementGroup createSimpleGroup() {

src/ray/core_worker/lib/java/io_ray_runtime_gcs_GlobalStateAccessor.cc

@@ -129,6 +129,32 @@ Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetActorCheckpointId(
   return nullptr;
 }
 
+JNIEXPORT jbyteArray JNICALL
+Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetPlacementGroupInfo(
+    JNIEnv *env, jobject o, jlong gcs_accessor_ptr, jbyteArray placement_group_id_bytes) {
+  const auto placement_group_id =
+      JavaByteArrayToId<ray::PlacementGroupID>(env, placement_group_id_bytes);
+  auto *gcs_accessor =
+      reinterpret_cast<ray::gcs::GlobalStateAccessor *>(gcs_accessor_ptr);
+  auto placement_group = gcs_accessor->GetPlacementGroupInfo(placement_group_id);
+  if (placement_group) {
+    return NativeStringToJavaByteArray(env, *placement_group);
+  }
+  return nullptr;
+}
+
+JNIEXPORT jobject JNICALL
+Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetAllPlacementGroupInfo(
+    JNIEnv *env, jobject o, jlong gcs_accessor_ptr) {
+  auto *gcs_accessor =
+      reinterpret_cast<ray::gcs::GlobalStateAccessor *>(gcs_accessor_ptr);
+  auto placement_group_info_list = gcs_accessor->GetAllPlacementGroupInfo();
+  return NativeVectorToJavaList<std::string>(
+      env, placement_group_info_list, [](JNIEnv *env, const std::string &str) {
+        return NativeStringToJavaByteArray(env, str);
+      });
+}
+
 #ifdef __cplusplus
 }
 #endif

src/ray/core_worker/lib/java/io_ray_runtime_gcs_GlobalStateAccessor.h

@@ -112,6 +112,26 @@ JNIEXPORT jbyteArray JNICALL
 Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetActorCheckpointId(JNIEnv *, jobject,
                                                                        jlong, jbyteArray);
 
+/*
+ * Class:     io_ray_runtime_gcs_GlobalStateAccessor
+ * Method:    nativeGetPlacementGroupInfo
+ * Signature: (J[B)[B
+ */
+JNIEXPORT jbyteArray JNICALL
+Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetPlacementGroupInfo(JNIEnv *, jobject,
+                                                                        jlong,
+                                                                        jbyteArray);
+
+/*
+ * Class:     io_ray_runtime_gcs_GlobalStateAccessor
+ * Method:    nativeGetAllPlacementGroupInfo
+ * Signature: (J)Ljava/util/List;
+ */
+JNIEXPORT jobject JNICALL
+Java_io_ray_runtime_gcs_GlobalStateAccessor_nativeGetAllPlacementGroupInfo(JNIEnv *,
+                                                                           jobject,
+                                                                           jlong);
+
 #ifdef __cplusplus
 }
 #endif

src/ray/core_worker/lib/java/io_ray_runtime_task_NativeTaskSubmitter.cc

@@ -283,6 +283,16 @@ Java_io_ray_runtime_task_NativeTaskSubmitter_nativeCreatePlacementGroup(
   return IdToJavaByteArray<ray::PlacementGroupID>(env, placement_group_id);
 }
 
+JNIEXPORT void JNICALL
+Java_io_ray_runtime_task_NativeTaskSubmitter_nativeRemovePlacementGroup(
+    JNIEnv *env, jclass p, jbyteArray placement_group_id_bytes) {
+  const auto placement_group_id =
+      JavaByteArrayToId<ray::PlacementGroupID>(env, placement_group_id_bytes);
+  auto status =
+      ray::CoreWorkerProcess::GetCoreWorker().RemovePlacementGroup(placement_group_id);
+  THROW_EXCEPTION_AND_RETURN_IF_NOT_OK(env, status, (void)0);
+}
+
 #ifdef __cplusplus
 }
 #endif

src/ray/core_worker/lib/java/io_ray_runtime_task_NativeTaskSubmitter.h

@@ -62,6 +62,15 @@ Java_io_ray_runtime_task_NativeTaskSubmitter_nativeCreatePlacementGroup(JNIEnv *
                                                                         jstring, jobject,
                                                                         jint);
 
+/*
+ * Class:     io_ray_runtime_task_NativeTaskSubmitter
+ * Method:    nativeRemovePlacementGroup
+ * Signature: ([B)V
+ */
+JNIEXPORT void JNICALL
+Java_io_ray_runtime_task_NativeTaskSubmitter_nativeRemovePlacementGroup(JNIEnv *, jclass,
+                                                                        jbyteArray);
+
 #ifdef __cplusplus
 }
 #endif

src/ray/core_worker/lib/java/jni_init.cc

@@ -225,9 +225,8 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
 
   java_placement_group_class =
       LoadClass(env, "io/ray/runtime/placementgroup/PlacementGroupImpl");
-  java_placement_group_id =
+  java_placement_group_id = env->GetFieldID(java_placement_group_class, "id",
-      env->GetFieldID(java_placement_group_class, "id",
+                                            "Lio/ray/api/id/PlacementGroupId;");
-                      "Lio/ray/runtime/placementgroup/PlacementGroupId;");
 
   java_actor_creation_options_class =
       LoadClass(env, "io/ray/api/options/ActorCreationOptions");