[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/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,
-          "Global state accessor native pointer must not be 0.");
+    validateGlobalStateAccessorPointer();
     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,
-          "Get all job info when global state accessor have been destroyed.");
+      validateGlobalStateAccessorPointer();
       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,
-          "Get all node info when global state accessor have been destroyed.");
+      validateGlobalStateAccessorPointer();
       return this.nativeGetAllNodeInfo(globalStateAccessorNativePointer);
     }
   }
@@ -72,16 +75,30 @@ public class GlobalStateAccessor {
    */
   public byte[] getNodeResourceInfo(UniqueId nodeId) {
     synchronized (GlobalStateAccessor.class) {
-      Preconditions.checkState(globalStateAccessorNativePointer != 0,
-          "Get resource info by node id when global state accessor have been destroyed.");
+      validateGlobalStateAccessorPointer();
       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,
-          "Get internal config when global state accessor have been destroyed.");
+      validateGlobalStateAccessorPointer();
       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/PlacementGroupId.java

@@ -1,58 +0,0 @@
-package io.ray.runtime.placementgroup;
-
-import io.ray.api.id.BaseId;
-import java.io.Serializable;
-import java.nio.ByteBuffer;
-import java.util.Arrays;
-import java.util.Random;
-
-/**
- * Represents the id of a placement group.
- */
-public class PlacementGroupId extends BaseId implements Serializable {
-
-  public static final int LENGTH = 16;
-
-  public static final PlacementGroupId NIL = nil();
-
-  private PlacementGroupId(byte[] id) {
-    super(id);
-  }
-
-  /**
-   * Creates a PlacementGroupId from the given ByteBuffer.
-   */
-  public static PlacementGroupId fromByteBuffer(ByteBuffer bb) {
-    return new PlacementGroupId(byteBuffer2Bytes(bb));
-  }
-
-  /**
-   * Create a PlacementGroupId instance according to the given bytes.
-   */
-  public static PlacementGroupId fromBytes(byte[] bytes) {
-    return new PlacementGroupId(bytes);
-  }
-
-  /**
-   * Generate a nil PlacementGroupId.
-   */
-  private static PlacementGroupId nil() {
-    byte[] b = new byte[LENGTH];
-    Arrays.fill(b, (byte) 0xFF);
-    return new PlacementGroupId(b);
-  }
-
-  /**
-   * Generate an PlacementGroupId with random value. Used for local mode and test only.
-   */
-  public static PlacementGroupId fromRandom() {
-    byte[] b = new byte[LENGTH];
-    new Random().nextBytes(b);
-    return new PlacementGroupId(b);
-  }
-
-  @Override
-  public int size() {
-    return LENGTH;
-  }
-}

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.
-     * @param id Id of the Placement Group.
+     * Set the 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.
-     * @param name Name of the Placement Group.
+     * Set the 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.
-     * @param bundles the bundles of the Placement Group.
+     * Set 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.
-     * @param strategy the placement strategy of the Placement Group.
+     * Set 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.
-     * @param state the state of the Placement Group.
+     * Set the placement 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()
-      .setName(name).setBundles(bundles).setStrategy(strategy).build();
+    PlacementGroupImpl placementGroup = new PlacementGroupImpl.Builder()
+        .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);
 
 }