Add placement group manager and some code in core_worker (#9120)

Co-authored-by: Lingxuan Zuo <skyzlxuan@gmail.com>

BUILD.bazel

@@ -1076,6 +1076,20 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "gcs_placement_group_manager_test",
+    srcs = [
+        "src/ray/gcs/gcs_server/test/gcs_placement_group_manager_test.cc",
+        "src/ray/gcs/gcs_server/test/gcs_server_test_util.h",
+    ],
+    copts = COPTS,
+    deps = [
+        ":gcs_server_lib",
+        ":gcs_test_util_lib",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_test(
     name = "gcs_placement_group_scheduler_test",
     srcs = [

src/ray/common/placement_group.cc

@@ -33,12 +33,8 @@ std::vector<BundleSpecification> PlacementGroupSpecification::GetBundles() const
   return bundles_;
 }
 
-Strategy PlacementGroupSpecification::GetStrategy() const {
+rpc::PlacementStrategy PlacementGroupSpecification::GetStrategy() const {
-  if (message_->strategy() == rpc::PlacementStrategy::PACK) {
+  return message_->strategy();
-    return Strategy::PACK;
-  } else {
-    return Strategy::SPREAD;
-  }
 }
 
 BundleSpecification PlacementGroupSpecification::GetBundle(int position) const {

src/ray/common/placement_group.h

@@ -21,11 +21,6 @@
 
 namespace ray {
 
-enum class Strategy {
-  PACK = 0x0,
-  SPREAD = 0x1,
-};
-
 class PlacementGroupSpecification : public MessageWrapper<rpc::PlacementGroupSpec> {
  public:
   /// Construct from a protobuf message object.
@@ -48,7 +43,7 @@ class PlacementGroupSpecification : public MessageWrapper<rpc::PlacementGroupSpe
   /// Return the bundles in this placement group.
   std::vector<BundleSpecification> GetBundles() const;
   /// Return the strategy of the placement group.
-  Strategy GetStrategy() const;
+  rpc::PlacementStrategy GetStrategy() const;
   /// Return the bundle by given index.
   BundleSpecification GetBundle(int position) const;
   /// Return the name of this placement group.
@@ -71,18 +66,19 @@ class PlacementGroupSpecBuilder {
   /// \return Reference to the builder object itself.
   PlacementGroupSpecBuilder &SetPlacementGroupSpec(
       const PlacementGroupID &placement_group_id, std::string name,
-      const std::vector<rpc::Bundle> &bundles, const rpc::PlacementStrategy strategy) {
+      const std::vector<std::unordered_map<std::string, double>> &bundles,
+      const rpc::PlacementStrategy strategy) {
     message_->set_placement_group_id(placement_group_id.Binary());
     message_->set_name(name);
     message_->set_strategy(strategy);
     for (int i = 0; i < bundles.size(); i++) {
-      rpc::Bundle bundle = bundles[i];
+      auto resources = bundles[i];
       auto message_bundle = message_->add_bundles();
       auto mutable_bundle_id = message_bundle->mutable_bundle_id();
       mutable_bundle_id->set_bundle_index(i);
       mutable_bundle_id->set_placement_group_id(placement_group_id.Binary());
-      message_bundle->mutable_unit_resources()->insert(bundle.unit_resources().begin(),
+      message_bundle->mutable_unit_resources()->insert(resources.begin(),
-                                                       bundle.unit_resources().end());
+                                                       resources.end());
     }
     return *this;
   }

src/ray/common/task/scheduling_resources.cc

@@ -683,7 +683,6 @@ void ResourceIdSet::CancelResourceReserve(const std::string &resource_name) {
     available_resources_.erase(iter_bundle);
   }
 }
-
 void ResourceIdSet::DeleteResource(const std::string &resource_name) {
   available_resources_.erase(resource_name);
 }

src/ray/common/task/scheduling_resources.h

@@ -429,6 +429,7 @@ class ResourceIdSet {
   /// \brief  remove a Bundle resource in the ResourceIdSet.
   ///
   /// \param resource_name the name of the resource to remove.
+
   void CancelResourceReserve(const std::string &resource_name);
   /// \brief Deletes a resource in the ResourceIdSet. This does not raise an exception,
   /// just deletes the resource. Tasks with acquired resources keep running.

src/ray/common/task/scheduling_resources_test.cc

@@ -63,14 +63,7 @@ TEST_F(SchedulingResourcesTest, ReturnBundleResources) {
   resource_labels.push_back(bundle_id.Binary() + "_" + "CPU");
   ResourceSet result_resource(resource_labels, resource_capacity);
   ASSERT_EQ(1, resource_set->IsEqual(result_resource));
-
   resource_set->ReturnBundleResources(bundle_id.Binary());
   ASSERT_EQ(1, resource_set->IsEqual(resource));
 }
-
 }  // namespace ray
-
-int main(int argc, char **argv) {
-  ::testing::InitGoogleTest(&argc, argv);
-  return RUN_ALL_TESTS();
-}

src/ray/core_worker/common.h

@@ -25,6 +25,7 @@
 namespace ray {
 
 using WorkerType = rpc::WorkerType;
+using PlacementOptions = std::pair<PlacementGroupID, int64_t>;
 
 // Return a string representation of the worker type.
 std::string WorkerTypeString(WorkerType type);
@@ -65,12 +66,13 @@ struct TaskOptions {
 /// Options for actor creation tasks.
 struct ActorCreationOptions {
   ActorCreationOptions() {}
-  ActorCreationOptions(int64_t max_restarts, int64_t max_task_retries,
+  ActorCreationOptions(
-                       int max_concurrency,
+      int64_t max_restarts, int64_t max_task_retries, int max_concurrency,
-                       const std::unordered_map<std::string, double> &resources,
+      const std::unordered_map<std::string, double> &resources,
-                       const std::unordered_map<std::string, double> &placement_resources,
+      const std::unordered_map<std::string, double> &placement_resources,
-                       const std::vector<std::string> &dynamic_worker_options,
+      const std::vector<std::string> &dynamic_worker_options, bool is_detached,
-                       bool is_detached, std::string &name, bool is_asyncio)
+      std::string &name, bool is_asyncio,
+      PlacementOptions placement_options = std::make_pair(PlacementGroupID::Nil(), -1))
       : max_restarts(max_restarts),
         max_task_retries(max_task_retries),
         max_concurrency(max_concurrency),
@@ -79,7 +81,8 @@ struct ActorCreationOptions {
         dynamic_worker_options(dynamic_worker_options),
         is_detached(is_detached),
         name(name),
-        is_asyncio(is_asyncio){};
+        is_asyncio(is_asyncio),
+        placement_options(placement_options){};
 
   /// Maximum number of times that the actor should be restarted if it dies
   /// unexpectedly. A value of -1 indicates infinite restarts. If it's 0, the
@@ -107,6 +110,27 @@ struct ActorCreationOptions {
   const std::string name;
   /// Whether to use async mode of direct actor call.
   const bool is_asyncio = false;
+  /// The placement_options include placement_group_id and bundle_index.
+  /// If the actor doesn't belong to a placement group, the placement_group_id will be
+  /// nil, and the bundle_index will be -1.
+  PlacementOptions placement_options;
+};
+
+using PlacementStrategy = rpc::PlacementStrategy;
+
+struct PlacementGroupCreationOptions {
+  PlacementGroupCreationOptions() {}
+  PlacementGroupCreationOptions(
+      const std::string &name, PlacementStrategy strategy,
+      const std::vector<std::unordered_map<std::string, double>> &bundles)
+      : name(name), strategy(strategy), bundles(bundles) {}
+
+  /// The strategy to place the bundle in Placement Group.
+  const PlacementStrategy strategy = rpc::PACK;
+  /// The resource bundles in this placement group.
+  const std::vector<std::unordered_map<std::string, double>> bundles;
+  /// The name of the placement group.
+  const std::string name;
 };
 
 }  // namespace ray

src/ray/core_worker/core_worker.cc

@@ -1168,6 +1168,21 @@ void CoreWorker::SubmitTask(const RayFunction &function,
   }
 }
 
+std::unordered_map<std::string, double> AddPlacementGroupConstraint(
+    const std::unordered_map<std::string, double> &resources,
+    PlacementGroupID placement_group_id, int64_t bundle_index) {
+  std::unordered_map<std::string, double> new_resources;
+  if (placement_group_id != PlacementGroupID::Nil()) {
+    for (auto iter = resources.begin(); iter != resources.end(); iter++) {
+      auto new_name =
+          placement_group_id.Hex() + std::to_string(bundle_index) + "_" + iter->first;
+      new_resources[new_name] = iter->second;
+    }
+    return new_resources;
+  }
+  return resources;
+}
+
 Status CoreWorker::CreateActor(const RayFunction &function,
                                const std::vector<std::unique_ptr<TaskArg>> &args,
                                const ActorCreationOptions &actor_creation_options,
@@ -1185,10 +1200,17 @@ Status CoreWorker::CreateActor(const RayFunction &function,
   const JobID job_id = worker_context_.GetCurrentJobID();
   std::vector<ObjectID> return_ids;
   TaskSpecBuilder builder;
+  auto new_placement_resources =
+      AddPlacementGroupConstraint(actor_creation_options.placement_resources,
+                                  actor_creation_options.placement_options.first,
+                                  actor_creation_options.placement_options.second);
+  auto new_resource = AddPlacementGroupConstraint(
+      actor_creation_options.resources, actor_creation_options.placement_options.first,
+      actor_creation_options.placement_options.second);
   BuildCommonTaskSpec(builder, job_id, actor_creation_task_id,
                       worker_context_.GetCurrentTaskID(), next_task_index, GetCallerId(),
-                      rpc_address_, function, args, 1, actor_creation_options.resources,
+                      rpc_address_, function, args, 1, new_resource,
-                      actor_creation_options.placement_resources, &return_ids);
+                      new_placement_resources, &return_ids);
   builder.SetActorCreationTaskSpec(
       actor_id, actor_creation_options.max_restarts,
       actor_creation_options.dynamic_worker_options,
@@ -1227,6 +1249,22 @@ Status CoreWorker::CreateActor(const RayFunction &function,
   return status;
 }
 
+Status CoreWorker::CreatePlacementGroup(
+    const PlacementGroupCreationOptions &placement_group_creation_options,
+    PlacementGroupID *return_placement_group_id) {
+  const PlacementGroupID placement_group_id = PlacementGroupID ::FromRandom();
+  PlacementGroupSpecBuilder builder;
+  builder.SetPlacementGroupSpec(placement_group_id, placement_group_creation_options.name,
+                                placement_group_creation_options.bundles,
+                                placement_group_creation_options.strategy);
+  PlacementGroupSpecification placement_group_spec = builder.Build();
+  *return_placement_group_id = placement_group_id;
+  RAY_LOG(INFO) << "Submitting Placement Group creation to GCS: " << placement_group_id;
+  RAY_CHECK_OK(
+      gcs_client_->PlacementGroups().AsyncCreatePlacementGroup(placement_group_spec));
+  return Status::OK();
+}
+
 void CoreWorker::SubmitActorTask(const ActorID &actor_id, const RayFunction &function,
                                  const std::vector<std::unique_ptr<TaskArg>> &args,
                                  const TaskOptions &task_options,

src/ray/core_worker/core_worker.h

@@ -17,6 +17,7 @@
 #include "absl/base/optimization.h"
 #include "absl/container/flat_hash_map.h"
 #include "ray/common/buffer.h"
+#include "ray/common/placement_group.h"
 #include "ray/core_worker/actor_handle.h"
 #include "ray/core_worker/actor_manager.h"
 #include "ray/core_worker/actor_reporter.h"
@@ -593,6 +594,17 @@ class CoreWorker : public rpc::CoreWorkerServiceHandler {
                      const ActorCreationOptions &actor_creation_options,
                      const std::string &extension_data, ActorID *actor_id);
 
+  /// Create a placement group.
+  ///
+  /// \param[in] function The remote function that generates the placement group object.
+  /// \param[in] placement_group_creation_options Options for this placement group
+  /// creation task. \param[out] placement_group_id ID of the created placement group.
+  /// This can be used to shedule actor in node \return Status error if placement group
+  /// creation fails, likely due to raylet failure.
+  Status CreatePlacementGroup(
+      const PlacementGroupCreationOptions &placement_group_creation_options,
+      PlacementGroupID *placement_group_id);
+
   /// Submit an actor task.
   ///
   /// \param[in] caller_id ID of the task submitter.

src/ray/gcs/accessor.h

@@ -15,6 +15,7 @@
 #pragma once
 
 #include "ray/common/id.h"
+#include "ray/common/placement_group.h"
 #include "ray/common/task/task_spec.h"
 #include "ray/gcs/callback.h"
 #include "ray/gcs/entry_change_notification.h"
@@ -711,6 +712,21 @@ class WorkerInfoAccessor {
   WorkerInfoAccessor() = default;
 };
 
+class PlacementGroupInfoAccessor {
+ public:
+  // TODO(AlisaWu): fill the accessor.
+  /// Create an placement group to GCS asynchronously.
+  ///
+  /// \param placement_group_spec The specification for the placement group creation task.
+  /// \param callback Callback that will be called after the placement group info is
+  /// written to GCS. \return Status
+  virtual Status AsyncCreatePlacementGroup(
+      const PlacementGroupSpecification &placement_group_spec) = 0;
+
+ protected:
+  PlacementGroupInfoAccessor() = default;
+};
+
 }  // namespace gcs
 
 }  // namespace ray

src/ray/gcs/gcs_client.h

@@ -134,6 +134,13 @@ class GcsClient : public std::enable_shared_from_this<GcsClient> {
     return *worker_accessor_;
   }
 
+  /// Get the sub-interface for accessing worker information in GCS.
+  /// This function is thread safe.
+  PlacementGroupInfoAccessor &PlacementGroups() {
+    RAY_CHECK(placement_group_accessor_ != nullptr);
+    return *placement_group_accessor_;
+  }
+
  protected:
   /// Constructor of GcsClient.
   ///
@@ -153,6 +160,7 @@ class GcsClient : public std::enable_shared_from_this<GcsClient> {
   std::unique_ptr<ErrorInfoAccessor> error_accessor_;
   std::unique_ptr<StatsInfoAccessor> stats_accessor_;
   std::unique_ptr<WorkerInfoAccessor> worker_accessor_;
+  std::unique_ptr<PlacementGroupInfoAccessor> placement_group_accessor_;
 };
 
 }  // namespace gcs

src/ray/gcs/gcs_client/service_based_accessor.cc

@@ -1383,5 +1383,28 @@ Status ServiceBasedWorkerInfoAccessor::AsyncAdd(
   return Status::OK();
 }
 
+ServiceBasedPlacementGroupInfoAccessor::ServiceBasedPlacementGroupInfoAccessor(
+    ServiceBasedGcsClient *client_impl)
+    : client_impl_(client_impl) {}
+
+Status ServiceBasedPlacementGroupInfoAccessor::AsyncCreatePlacementGroup(
+    const ray::PlacementGroupSpecification &placement_group_spec) {
+  rpc::CreatePlacementGroupRequest request;
+  request.mutable_placement_group_spec()->CopyFrom(placement_group_spec.GetMessage());
+  client_impl_->GetGcsRpcClient().CreatePlacementGroup(
+      request, [placement_group_spec](const Status &,
+                                      const rpc::CreatePlacementGroupReply &reply) {
+        auto status =
+            reply.status().code() == (int)StatusCode::OK
+                ? Status()
+                : Status(StatusCode(reply.status().code()), reply.status().message());
+        if (status.ok()) {
+          RAY_LOG(DEBUG) << "Finished registering placement group. placement group id = "
+                         << placement_group_spec.PlacementGroupId();
+        }
+      });
+  return Status::OK();
+}
+
 }  // namespace gcs
 }  // namespace ray

src/ray/gcs/gcs_client/service_based_accessor.h

@@ -409,5 +409,23 @@ class ServiceBasedWorkerInfoAccessor : public WorkerInfoAccessor {
   ServiceBasedGcsClient *client_impl_;
 };
 
+/// \class ServiceBasedPlacementGroupInfoAccessor
+/// ServiceBasedPlacementGroupInfoAccessor is an implementation of
+/// `PlacementGroupInfoAccessor` that uses GCS Service as the backend.
+
+class ServiceBasedPlacementGroupInfoAccessor : public PlacementGroupInfoAccessor {
+  // TODO(AlisaWu):fill the ServiceAccessor.
+ public:
+  explicit ServiceBasedPlacementGroupInfoAccessor(ServiceBasedGcsClient *client_impl);
+
+  virtual ~ServiceBasedPlacementGroupInfoAccessor() = default;
+
+  Status AsyncCreatePlacementGroup(
+      const PlacementGroupSpecification &placement_group_spec) override;
+
+ private:
+  ServiceBasedGcsClient *client_impl_;
+};
+
 }  // namespace gcs
 }  // namespace ray

src/ray/gcs/gcs_client/service_based_gcs_client.cc

@@ -75,6 +75,7 @@ Status ServiceBasedGcsClient::Connect(boost::asio::io_service &io_service) {
   stats_accessor_.reset(new ServiceBasedStatsInfoAccessor(this));
   error_accessor_.reset(new ServiceBasedErrorInfoAccessor(this));
   worker_accessor_.reset(new ServiceBasedWorkerInfoAccessor(this));
+  placement_group_accessor_.reset(new ServiceBasedPlacementGroupInfoAccessor(this));
 
   // Init gcs service address check timer.
   detect_timer_.reset(new boost::asio::deadline_timer(io_service));

src/ray/gcs/gcs_server/gcs_placement_group_manager.cc

@@ -54,5 +54,131 @@ const rpc::PlacementGroupTableData &GcsPlacementGroup::GetPlacementGroupTableDat
   return placement_group_table_data_;
 }
 
+/////////////////////////////////////////////////////////////////////////////////////////
+
+GcsPlacementGroupManager::GcsPlacementGroupManager(
+    boost::asio::io_context &io_context,
+    std::shared_ptr<GcsPlacementGroupSchedulerInterface> scheduler,
+    std::shared_ptr<gcs::GcsTableStorage> gcs_table_storage)
+    : gcs_placement_group_scheduler_(std::move(scheduler)),
+      gcs_table_storage_(gcs_table_storage),
+      reschedule_timer_(io_context) {}
+
+void GcsPlacementGroupManager::RegisterPlacementGroup(
+    const ray::rpc::CreatePlacementGroupRequest &request,
+    std::function<void(std::shared_ptr<GcsPlacementGroup>)> callback) {
+  RAY_CHECK(callback);
+  const auto &placement_group_spec = request.placement_group_spec();
+  auto placement_group_id =
+      PlacementGroupID::FromBinary(placement_group_spec.placement_group_id());
+
+  auto placement_group = std::make_shared<GcsPlacementGroup>(request);
+  // Mark the callback as pending and invoke it after the placement_group has been
+  // successfully created.
+  placement_group_to_register_callbacks_[placement_group_id].emplace_back(
+      std::move(callback));
+  RAY_CHECK(registered_placement_groups_
+                .emplace(placement_group->GetPlacementGroupID(), placement_group)
+                .second);
+  pending_placement_groups_.emplace_back(std::move(placement_group));
+  SchedulePendingPlacementGroups();
+}
+
+PlacementGroupID GcsPlacementGroupManager::GetPlacementGroupIDByName(
+    const std::string &name) {
+  PlacementGroupID placement_group_id = PlacementGroupID::Nil();
+  for (auto placement_group_pair : registered_placement_groups_) {
+    auto placement_group = placement_group_pair.second;
+    if (placement_group->GetName() == name) {
+      placement_group_id = placement_group_pair.first;
+      break;
+    }
+  }
+  return placement_group_id;
+}
+
+void GcsPlacementGroupManager::OnPlacementGroupCreationFailed(
+    std::shared_ptr<GcsPlacementGroup> placement_group) {
+  // We will attempt to schedule this placement_group once an eligible node is
+  // registered.
+  pending_placement_groups_.emplace_back(std::move(placement_group));
+  is_creating_ = false;
+  ScheduleTick();
+}
+
+void GcsPlacementGroupManager::OnPlacementGroupCreationSuccess(
+    std::shared_ptr<GcsPlacementGroup> placement_group) {
+  auto placement_group_id = placement_group->GetPlacementGroupID();
+  RAY_CHECK(registered_placement_groups_.count(placement_group_id) > 0);
+  placement_group->UpdateState(rpc::PlacementGroupTableData::ALIVE);
+
+  auto placement_group_table_data = placement_group->GetPlacementGroupTableData();
+  // The backend storage is reliable in the future, so the status must be ok.
+  RAY_CHECK_OK(gcs_table_storage_->PlacementGroupTable().Put(
+      placement_group_id, placement_group_table_data, [](Status status) {}));
+
+  // Invoke all callbacks for all registration requests of this placement_group
+  // (duplicated requests are included) and remove all of them from
+  // placement_group_to_register_callbacks_.
+  auto iter = placement_group_to_register_callbacks_.find(placement_group_id);
+  if (iter != placement_group_to_register_callbacks_.end()) {
+    for (auto &callback : iter->second) {
+      callback(placement_group);
+    }
+    placement_group_to_register_callbacks_.erase(iter);
+  }
+  is_creating_ = false;
+  SchedulePendingPlacementGroups();
+}
+
+void GcsPlacementGroupManager::SchedulePendingPlacementGroups() {
+  if (pending_placement_groups_.empty() || is_creating_) {
+    return;
+  }
+  is_creating_ = true;
+  gcs_placement_group_scheduler_->Schedule(
+      *pending_placement_groups_.begin(),
+      [this](std::shared_ptr<GcsPlacementGroup> placement_group) {
+        OnPlacementGroupCreationFailed(std::move(placement_group));
+      },
+      [this](std::shared_ptr<GcsPlacementGroup> placement_group) {
+        OnPlacementGroupCreationSuccess(std::move(placement_group));
+      });
+  pending_placement_groups_.pop_front();
+}
+
+void GcsPlacementGroupManager::HandleCreatePlacementGroup(
+    const ray::rpc::CreatePlacementGroupRequest &request,
+    ray::rpc::CreatePlacementGroupReply *reply,
+    ray::rpc::SendReplyCallback send_reply_callback) {
+  auto placement_group_id =
+      PlacementGroupID::FromBinary(request.placement_group_spec().placement_group_id());
+
+  RAY_LOG(INFO) << "Registering placement group, placement group id = "
+                << placement_group_id;
+  RegisterPlacementGroup(
+      request, [reply, send_reply_callback, placement_group_id](
+                   std::shared_ptr<gcs::GcsPlacementGroup> placement_group) {
+        RAY_LOG(INFO) << "Registered placement group, placement group id = "
+                      << placement_group_id;
+        GCS_RPC_SEND_REPLY(send_reply_callback, reply, Status::OK());
+      });
+  auto placement_group = std::make_shared<GcsPlacementGroup>(request);
+  auto placement_group_table_data = placement_group->GetPlacementGroupTableData();
+  RAY_CHECK_OK(gcs_table_storage_->PlacementGroupTable().Put(
+      placement_group_id, placement_group_table_data, [](Status status) {}));
+}
+
+void GcsPlacementGroupManager::ScheduleTick() {
+  reschedule_timer_.expires_from_now(boost::posix_time::milliseconds(5));
+  reschedule_timer_.async_wait([this](const boost::system::error_code &error) {
+    if (error == boost::system::errc::operation_canceled) {
+      return;
+    } else {
+      SchedulePendingPlacementGroups();
+    }
+  });
+}
+
 }  // namespace gcs
 }  // namespace ray

src/ray/gcs/gcs_server/gcs_placement_group_manager.h

@@ -47,7 +47,7 @@ class GcsPlacementGroup {
     const auto &placement_group_spec = request.placement_group_spec();
     placement_group_table_data_.set_placement_group_id(
         placement_group_spec.placement_group_id());
-
+    placement_group_table_data_.set_name(placement_group_spec.name());
     placement_group_table_data_.set_state(rpc::PlacementGroupTableData::PENDING);
     placement_group_table_data_.mutable_bundles()->CopyFrom(
         placement_group_spec.bundles());
@@ -78,5 +78,100 @@ class GcsPlacementGroup {
   /// state of the gcs placement_group and so on (see gcs.proto).
   rpc::PlacementGroupTableData placement_group_table_data_;
 };
+
+using RegisterPlacementGroupCallback =
+    std::function<void(std::shared_ptr<GcsPlacementGroup>)>;
+/// GcsPlacementGroupManager is responsible for managing the lifecycle of all placement
+/// group. This class is not thread-safe.
+/// The placementGroup will be added into queue and set the status as pending first and
+/// use SchedulePendingPlacementGroups(). The SchedulePendingPlacementGroups() will get
+/// the head of the queue and schedule it. If schedule success, using the
+/// SchedulePendingPlacementGroups() Immediately. else wait for a short time beforw using
+/// SchedulePendingPlacementGroups() next time.
+class GcsPlacementGroupManager : public rpc::PlacementGroupInfoHandler {
+ public:
+  /// Create a GcsPlacementGroupManager
+  ///
+  /// \param io_context The event loop to run the monitor on.
+  /// \param scheduler Used to schedule placement group creation tasks.
+  /// \param gcs_table_storage Used to flush placement group data to storage.
+  explicit GcsPlacementGroupManager(
+      boost::asio::io_context &io_context,
+      std::shared_ptr<GcsPlacementGroupSchedulerInterface> scheduler,
+      std::shared_ptr<gcs::GcsTableStorage> gcs_table_storage);
+
+  ~GcsPlacementGroupManager() = default;
+
+  void HandleCreatePlacementGroup(const rpc::CreatePlacementGroupRequest &request,
+                                  rpc::CreatePlacementGroupReply *reply,
+                                  rpc::SendReplyCallback send_reply_callback) override;
+
+  /// Register placement_group asynchronously.
+  ///
+  /// \param request Contains the meta info to create the placement_group.
+  /// \param callback Will be invoked after the placement_group is created successfully or
+  /// be invoked immediately if the placement_group is already registered to
+  /// `registered_placement_groups_` and its state is `ALIVE`. The callback will not be
+  /// called in this case.
+  void RegisterPlacementGroup(const rpc::CreatePlacementGroupRequest &request,
+                              RegisterPlacementGroupCallback callback);
+
+  /// Schedule placement_groups in the `pending_placement_groups_` queue.
+  /// This function is exposed for testing only.
+  void SchedulePendingPlacementGroups();
+
+  /// Get the placement_group ID for the named placement_group. Returns nil if the
+  /// placement_group was not found.
+  /// \param name The name of the  placement_group to look up.
+  /// \returns PlacementGroupID The ID of the placement_group. Nil if the
+  /// placement_group was not found.
+  PlacementGroupID GetPlacementGroupIDByName(const std::string &name);
+
+  /// Handle placement_group creation task failure. This should be called when scheduling
+  /// an placement_group creation task is infeasible.
+  ///
+  /// \param placement_group The placement_group whose creation task is infeasible.
+  void OnPlacementGroupCreationFailed(std::shared_ptr<GcsPlacementGroup> placement_group);
+
+  /// Handle placement_group creation task success. This should be called when the
+  /// placement_group creation task has been scheduled successfully.
+  ///
+  /// \param placement_group The placement_group that has been created.
+  void OnPlacementGroupCreationSuccess(
+      std::shared_ptr<GcsPlacementGroup> placement_group);
+
+ private:
+  /// Schedule another tick after a short time.
+  void ScheduleTick();
+
+  /// Callbacks of placement_group registration requests that are not yet flushed.
+  /// This map is used to filter duplicated messages from a Driver/Worker caused by some
+  /// network problems.
+  ///
+  /// Since the GRPC message received by the GCS side is out of order, it can not be
+  /// determined that the last callback is the valid one. Therefore, the repeated
+  /// callbacks are recorded in the form of vector without distinction. When the operation
+  /// is successful, all callbacks will be triggered. One of them must be valid, and the
+  /// rest invalid callbacks will not have any effect even if they are called.
+  absl::flat_hash_map<PlacementGroupID, std::vector<RegisterPlacementGroupCallback>>
+      placement_group_to_register_callbacks_;
+  /// All registered placement_groups (pending placement_groups are also included).
+  absl::flat_hash_map<PlacementGroupID, std::shared_ptr<GcsPlacementGroup>>
+      registered_placement_groups_;
+  /// The pending placement_groups which will not be scheduled until there's a resource
+  /// change.
+  std::deque<std::shared_ptr<GcsPlacementGroup>> pending_placement_groups_;
+  /// The scheduler to schedule all registered placement_groups.
+  std::shared_ptr<gcs::GcsPlacementGroupSchedulerInterface>
+      gcs_placement_group_scheduler_;
+  /// Used to update placement group information upon creation, deletion, etc.
+  std::shared_ptr<gcs::GcsTableStorage> gcs_table_storage_;
+  /// If a placement group is creating
+  bool is_creating_ = false;
+
+  /// A timer that ticks every schedule failure milliseconds.
+  boost::asio::deadline_timer reschedule_timer_;
+};
+
 }  // namespace gcs
 }  // namespace ray

src/ray/gcs/gcs_server/gcs_placement_group_scheduler.cc

@@ -188,8 +188,8 @@ void GcsPlacementGroupScheduler::ReserveResourceFromNode(
             if (iter->second.empty()) {
               node_to_bundles_when_leasing_.erase(iter);
             }
+            callback(status, reply);
           }
-          callback(status, reply);
         }
       });
   if (!status.ok()) {
@@ -229,7 +229,7 @@ void GcsPlacementGroupScheduler::CancelResourceReserve(
               });
         }
       });
-}  // namespace gcs
+}
 
 std::shared_ptr<ResourceReserveInterface>
 GcsPlacementGroupScheduler::GetOrConnectLeaseClient(const rpc::Address &raylet_address) {

src/ray/gcs/gcs_server/gcs_server.cc

@@ -19,6 +19,7 @@
 #include "gcs_job_manager.h"
 #include "gcs_node_manager.h"
 #include "gcs_object_manager.h"
+#include "gcs_placement_group_manager.h"
 #include "gcs_worker_manager.h"
 #include "ray/common/network_util.h"
 #include "ray/common/ray_config.h"
@@ -60,6 +61,9 @@ void GcsServer::Start() {
   // Init gcs actor manager.
   InitGcsActorManager();
 
+  // Init gcs placement group manager.
+  InitGcsPlacementGroupManager();
+
   // Register rpc service.
   gcs_object_manager_ = InitObjectManager();
   object_info_service_.reset(
@@ -79,6 +83,10 @@ void GcsServer::Start() {
       new rpc::ActorInfoGrpcService(main_service_, *gcs_actor_manager_));
   rpc_server_.RegisterService(*actor_info_service_);
 
+  placement_group_info_service_.reset(new rpc::PlacementGroupInfoGrpcService(
+      main_service_, *gcs_placement_group_manager_));
+  rpc_server_.RegisterService(*placement_group_info_service_);
+
   node_info_service_.reset(
       new rpc::NodeInfoGrpcService(main_service_, *gcs_node_manager_));
   rpc_server_.RegisterService(*node_info_service_);
@@ -210,6 +218,22 @@ void GcsServer::InitGcsJobManager() {
   });
 }
 
+void GcsServer::InitGcsPlacementGroupManager() {
+  RAY_CHECK(gcs_table_storage_ != nullptr && gcs_node_manager_ != nullptr);
+  auto scheduler = std::make_shared<GcsPlacementGroupScheduler>(
+      main_service_, gcs_table_storage_, *gcs_node_manager_,
+      /*lease_client_factory=*/
+      [this](const rpc::Address &address) {
+        auto node_manager_worker_client = rpc::NodeManagerWorkerClient::make(
+            address.ip_address(), address.port(), client_call_manager_);
+        return std::make_shared<ray::raylet::RayletClient>(
+            std::move(node_manager_worker_client));
+      });
+
+  gcs_placement_group_manager_ = std::make_shared<GcsPlacementGroupManager>(
+      main_service_, scheduler, gcs_table_storage_);
+}
+
 std::unique_ptr<GcsObjectManager> GcsServer::InitObjectManager() {
   return std::unique_ptr<GcsObjectManager>(
       new GcsObjectManager(gcs_table_storage_, gcs_pub_sub_, *gcs_node_manager_));

src/ray/gcs/gcs_server/gcs_server.h

@@ -40,6 +40,7 @@ class GcsNodeManager;
 class GcsActorManager;
 class GcsJobManager;
 class GcsWorkerManager;
+class GcsPlacementGroupManager;
 
 /// The GcsServer will take over all requests from ServiceBasedGcsClient and transparent
 /// transmit the command to the backend reliable storage for the time being.
@@ -85,6 +86,9 @@ class GcsServer {
   /// Initialize the gcs job manager.
   virtual void InitGcsJobManager();
 
+  /// Initialize the gcs placement group manager.
+  virtual void InitGcsPlacementGroupManager();
+
   /// The object manager
   virtual std::unique_ptr<GcsObjectManager> InitObjectManager();
 
@@ -122,6 +126,8 @@ class GcsServer {
   std::shared_ptr<GcsRedisFailureDetector> gcs_redis_failure_detector_;
   /// The gcs actor manager
   std::shared_ptr<GcsActorManager> gcs_actor_manager_;
+  /// The gcs placement group manager
+  std::shared_ptr<GcsPlacementGroupManager> gcs_placement_group_manager_;
   /// Job info handler and service
   std::unique_ptr<GcsJobManager> gcs_job_manager_;
   std::unique_ptr<rpc::JobInfoGrpcService> job_info_service_;
@@ -145,6 +151,9 @@ class GcsServer {
   std::unique_ptr<GcsWorkerManager> gcs_worker_manager_;
   /// Worker info service
   std::unique_ptr<rpc::WorkerInfoGrpcService> worker_info_service_;
+  /// Placement Group info handler and service
+  std::unique_ptr<rpc::PlacementGroupInfoHandler> placement_group_info_handler_;
+  std::unique_ptr<rpc::PlacementGroupInfoGrpcService> placement_group_info_service_;
   /// Backend client
   std::shared_ptr<RedisGcsClient> redis_gcs_client_;
   /// A publisher for publishing gcs messages.

src/ray/gcs/gcs_server/gcs_table_storage.cc

@@ -128,6 +128,7 @@ template class GcsTableWithJobId<TaskID, TaskTableData>;
 template class GcsTableWithJobId<TaskID, TaskLeaseData>;
 template class GcsTableWithJobId<TaskID, TaskReconstructionData>;
 template class GcsTableWithJobId<ObjectID, ObjectTableDataList>;
+template class GcsTable<PlacementGroupID, PlacementGroupTableData>;
 template class GcsTable<PlacementGroupID, ScheduleData>;
 
 }  // namespace gcs

src/ray/gcs/gcs_server/gcs_table_storage.h

@@ -33,6 +33,7 @@ using rpc::HeartbeatTableData;
 using rpc::JobTableData;
 using rpc::ObjectTableData;
 using rpc::ObjectTableDataList;
+using rpc::PlacementGroupTableData;
 using rpc::ProfileTableData;
 using rpc::ResourceMap;
 using rpc::ResourceTableData;
@@ -154,6 +155,15 @@ class GcsActorTable : public GcsTableWithJobId<ActorID, ActorTableData> {
   JobID GetJobIdFromKey(const ActorID &key) override { return key.JobId(); }
 };
 
+class GcsPlacementGroupTable
+    : public GcsTable<PlacementGroupID, PlacementGroupTableData> {
+ public:
+  explicit GcsPlacementGroupTable(std::shared_ptr<StoreClient> &store_client)
+      : GcsTable(store_client) {
+    table_name_ = TablePrefix_Name(TablePrefix::PLACEMENT_GROUP);
+  }
+};
+
 class GcsActorCheckpointTable : public GcsTable<ActorCheckpointID, ActorCheckpointData> {
  public:
   explicit GcsActorCheckpointTable(std::shared_ptr<StoreClient> &store_client)
@@ -307,6 +317,11 @@ class GcsTableStorage {
     return *actor_table_;
   }
 
+  GcsPlacementGroupTable &PlacementGroupTable() {
+    RAY_CHECK(placement_group_table_ != nullptr);
+    return *placement_group_table_;
+  }
+
   GcsActorCheckpointTable &ActorCheckpointTable() {
     RAY_CHECK(actor_checkpoint_table_ != nullptr);
     return *actor_checkpoint_table_;
@@ -386,6 +401,7 @@ class GcsTableStorage {
   std::shared_ptr<StoreClient> store_client_;
   std::unique_ptr<GcsJobTable> job_table_;
   std::unique_ptr<GcsActorTable> actor_table_;
+  std::unique_ptr<GcsPlacementGroupTable> placement_group_table_;
   std::unique_ptr<GcsActorCheckpointTable> actor_checkpoint_table_;
   std::unique_ptr<GcsActorCheckpointIdTable> actor_checkpoint_id_table_;
   std::unique_ptr<GcsTaskTable> task_table_;
@@ -394,8 +410,8 @@ class GcsTableStorage {
   std::unique_ptr<GcsObjectTable> object_table_;
   std::unique_ptr<GcsNodeTable> node_table_;
   std::unique_ptr<GcsNodeResourceTable> node_resource_table_;
-  std::unique_ptr<GcsPlacementGroupScheduleTable> placement_group_schedule_table_;
   std::unique_ptr<GcsHeartbeatTable> heartbeat_table_;
+  std::unique_ptr<GcsPlacementGroupScheduleTable> placement_group_schedule_table_;
   std::unique_ptr<GcsHeartbeatBatchTable> heartbeat_batch_table_;
   std::unique_ptr<GcsErrorInfoTable> error_info_table_;
   std::unique_ptr<GcsProfileTable> profile_table_;
@@ -412,6 +428,7 @@ class RedisGcsTableStorage : public GcsTableStorage {
     store_client_ = std::make_shared<RedisStoreClient>(redis_client);
     job_table_.reset(new GcsJobTable(store_client_));
     actor_table_.reset(new GcsActorTable(store_client_));
+    placement_group_table_.reset(new GcsPlacementGroupTable(store_client_));
     actor_checkpoint_table_.reset(new GcsActorCheckpointTable(store_client_));
     actor_checkpoint_id_table_.reset(new GcsActorCheckpointIdTable(store_client_));
     task_table_.reset(new GcsTaskTable(store_client_));
@@ -442,6 +459,7 @@ class InMemoryGcsTableStorage : public GcsTableStorage {
     store_client_ = std::make_shared<InMemoryStoreClient>(main_io_service);
     job_table_.reset(new GcsJobTable(store_client_));
     actor_table_.reset(new GcsActorTable(store_client_));
+    placement_group_table_.reset(new GcsPlacementGroupTable(store_client_));
     actor_checkpoint_table_.reset(new GcsActorCheckpointTable(store_client_));
     actor_checkpoint_id_table_.reset(new GcsActorCheckpointIdTable(store_client_));
     task_table_.reset(new GcsTaskTable(store_client_));

src/ray/gcs/gcs_server/test/gcs_placement_group_manager_test.cc

@@ -0,0 +1,132 @@
+// Copyright 2017 The Ray Authors.
+//
+// Licensed 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.
+
+#include <ray/gcs/gcs_server/test/gcs_server_test_util.h>
+#include <ray/gcs/test/gcs_test_util.h>
+
+#include <memory>
+
+#include "gtest/gtest.h"
+
+namespace ray {
+
+using ::testing::_;
+
+class MockPlacementGroupScheduler : public gcs::GcsPlacementGroupSchedulerInterface {
+ public:
+  MockPlacementGroupScheduler() {}
+
+  void Schedule(std::shared_ptr<gcs::GcsPlacementGroup> placement_group,
+                std::function<void(std::shared_ptr<gcs::GcsPlacementGroup>)>
+                    schedule_failure_handler = nullptr,
+                std::function<void(std::shared_ptr<gcs::GcsPlacementGroup>)>
+                    schedule_success_handler = nullptr) {
+    placement_groups.push_back(placement_group);
+  }
+
+  std::vector<std::shared_ptr<gcs::GcsPlacementGroup>> placement_groups;
+};
+
+class GcsPlacementGroupManagerTest : public ::testing::Test {
+ public:
+  GcsPlacementGroupManagerTest()
+      : mock_placement_group_scheduler_(new MockPlacementGroupScheduler()) {
+    gcs_table_storage_ = std::make_shared<gcs::InMemoryGcsTableStorage>(io_service_);
+    gcs_placement_group_manager_.reset(new gcs::GcsPlacementGroupManager(
+        io_service_, mock_placement_group_scheduler_, gcs_table_storage_));
+  }
+
+  boost::asio::io_service io_service_;
+  std::shared_ptr<gcs::GcsTableStorage> gcs_table_storage_;
+  std::shared_ptr<MockPlacementGroupScheduler> mock_placement_group_scheduler_;
+  std::unique_ptr<gcs::GcsPlacementGroupManager> gcs_placement_group_manager_;
+};
+
+TEST_F(GcsPlacementGroupManagerTest, TestBasic) {
+  auto create_placement_group_request = Mocker::GenCreatePlacementGroupRequest();
+  std::vector<std::shared_ptr<gcs::GcsPlacementGroup>> finished_placement_groups;
+  gcs_placement_group_manager_->RegisterPlacementGroup(
+      create_placement_group_request,
+      [&finished_placement_groups](
+          std::shared_ptr<gcs::GcsPlacementGroup> placement_group) {
+        finished_placement_groups.emplace_back(placement_group);
+      });
+  ASSERT_EQ(finished_placement_groups.size(), 0);
+  ASSERT_EQ(mock_placement_group_scheduler_->placement_groups.size(), 1);
+  auto placement_group = mock_placement_group_scheduler_->placement_groups.back();
+  mock_placement_group_scheduler_->placement_groups.pop_back();
+
+  gcs_placement_group_manager_->OnPlacementGroupCreationSuccess(placement_group);
+  ASSERT_EQ(finished_placement_groups.size(), 1);
+  ASSERT_EQ(placement_group->GetState(), rpc::PlacementGroupTableData::ALIVE);
+}
+
+TEST_F(GcsPlacementGroupManagerTest, TestSchedulingFailed) {
+  auto create_placement_group_request = Mocker::GenCreatePlacementGroupRequest();
+  std::vector<std::shared_ptr<gcs::GcsPlacementGroup>> finished_placement_groups;
+  gcs_placement_group_manager_->RegisterPlacementGroup(
+      create_placement_group_request,
+      [&finished_placement_groups](
+          std::shared_ptr<gcs::GcsPlacementGroup> placement_group) {
+        finished_placement_groups.emplace_back(placement_group);
+      });
+
+  ASSERT_EQ(finished_placement_groups.size(), 0);
+  ASSERT_EQ(mock_placement_group_scheduler_->placement_groups.size(), 1);
+  auto placement_group = mock_placement_group_scheduler_->placement_groups.back();
+  mock_placement_group_scheduler_->placement_groups.clear();
+
+  gcs_placement_group_manager_->OnPlacementGroupCreationFailed(placement_group);
+  gcs_placement_group_manager_->SchedulePendingPlacementGroups();
+  ASSERT_EQ(mock_placement_group_scheduler_->placement_groups.size(), 1);
+  mock_placement_group_scheduler_->placement_groups.clear();
+  ASSERT_EQ(finished_placement_groups.size(), 0);
+
+  // Check that the placement_group is in state `ALIVE`.
+  gcs_placement_group_manager_->OnPlacementGroupCreationSuccess(placement_group);
+  ASSERT_EQ(finished_placement_groups.size(), 1);
+  ASSERT_EQ(placement_group->GetState(), rpc::PlacementGroupTableData::ALIVE);
+}
+
+TEST_F(GcsPlacementGroupManagerTest, TestGetPlacementGroupIDByName) {
+  auto create_placement_group_request =
+      Mocker::GenCreatePlacementGroupRequest("test_name");
+  std::vector<std::shared_ptr<gcs::GcsPlacementGroup>> finished_placement_groups;
+  gcs_placement_group_manager_->RegisterPlacementGroup(
+      create_placement_group_request,
+      [&finished_placement_groups](
+          std::shared_ptr<gcs::GcsPlacementGroup> placement_group) {
+        finished_placement_groups.emplace_back(placement_group);
+      });
+
+  ASSERT_EQ(finished_placement_groups.size(), 0);
+  ASSERT_EQ(mock_placement_group_scheduler_->placement_groups.size(), 1);
+  auto placement_group = mock_placement_group_scheduler_->placement_groups.back();
+  mock_placement_group_scheduler_->placement_groups.pop_back();
+
+  gcs_placement_group_manager_->OnPlacementGroupCreationSuccess(placement_group);
+  ASSERT_EQ(finished_placement_groups.size(), 1);
+  ASSERT_EQ(placement_group->GetState(), rpc::PlacementGroupTableData::ALIVE);
+  ASSERT_EQ(
+      gcs_placement_group_manager_->GetPlacementGroupIDByName("test_name"),
+      PlacementGroupID::FromBinary(
+          create_placement_group_request.placement_group_spec().placement_group_id()));
+}
+
+}  // namespace ray
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

src/ray/gcs/gcs_server/test/gcs_placement_group_scheduler_test.cc

@@ -163,8 +163,8 @@ TEST_F(GcsPlacementGroupSchedulerTest, TestSchedulePlacementGroupReturnResource)
   ASSERT_TRUE(raylet_client_->GrantResourceReserve());
   ASSERT_TRUE(raylet_client_->GrantResourceReserve(false));
   ASSERT_EQ(1, raylet_client_->num_return_requested);
-  //   // Reply the placement_group creation request, then the placement_group should be
+  // Reply the placement_group creation request, then the placement_group should be
-  //   scheduled successfully.
+  //  scheduled successfully.
   ASSERT_EQ(1, failure_placement_groups_.size());
   ASSERT_EQ(0, success_placement_groups_.size());
   ASSERT_EQ(placement_group, failure_placement_groups_.front());

src/ray/gcs/test/gcs_test_util.h

@@ -64,7 +64,8 @@ struct Mocker {
   }
 
   static PlacementGroupSpecification GenPlacementGroupCreation(
-      const std::string &name, std::vector<rpc::Bundle> &bundles,
+      const std::string &name,
+      std::vector<std::unordered_map<std::string, double>> &bundles,
       rpc::PlacementStrategy strategy) {
     PlacementGroupSpecBuilder builder;
 
@@ -76,9 +77,10 @@ struct Mocker {
   static rpc::CreatePlacementGroupRequest GenCreatePlacementGroupRequest(
       const std::string name = "") {
     rpc::CreatePlacementGroupRequest request;
-    std::vector<rpc::Bundle> bundles;
+    std::vector<std::unordered_map<std::string, double>> bundles;
     rpc::PlacementStrategy strategy = rpc::PlacementStrategy::SPREAD;
-    rpc::Bundle bundle;
+    std::unordered_map<std::string, double> bundle;
+    bundle["CPU"] = 1.0;
     bundles.push_back(bundle);
     bundles.push_back(bundle);
     auto placement_group_creation_spec =
@@ -87,7 +89,6 @@ struct Mocker {
         placement_group_creation_spec.GetMessage());
     return request;
   }
-
   static std::shared_ptr<rpc::GcsNodeInfo> GenNodeInfo(
       uint16_t port = 0, const std::string address = "127.0.0.1") {
     auto node = std::make_shared<rpc::GcsNodeInfo>();

src/ray/protobuf/gcs.proto

@@ -46,6 +46,7 @@ enum TablePrefix {
   INTERNAL_CONFIG = 20;
   TABLE_PREFIX_MAX = 21;
   PLACEMENT_GROUP_SCHEDULE = 22;
+  PLACEMENT_GROUP = 23;
 }
 
 // The channel that Add operations to the Table should be published on, if any.

src/ray/protobuf/gcs_service.proto

@@ -162,6 +162,13 @@ service ActorInfoGcsService {
       returns (GetActorCheckpointIDReply);
 }
 
+// Service for placement group info access.
+service PlacementGroupInfoGcsService {
+  // Create placement group via gcs service
+  rpc CreatePlacementGroup(CreatePlacementGroupRequest)
+      returns (CreatePlacementGroupReply);
+}
+
 message RegisterNodeRequest {
   // Info of node.
   GcsNodeInfo node_info = 1;

src/ray/rpc/gcs_server/gcs_rpc_client.h

@@ -247,6 +247,10 @@ class GcsRpcClient {
   VOID_GCS_RPC_CLIENT_METHOD(WorkerInfoGcsService, AddWorkerInfo,
                              worker_info_grpc_client_, )
 
+  /// Create placement group via GCS Service.
+  VOID_GCS_RPC_CLIENT_METHOD(PlacementGroupInfoGcsService, CreatePlacementGroup,
+                             placement_group_info_grpc_client_, )
+
  private:
   std::function<void(GcsServiceFailureType)> gcs_service_failure_detected_;
 
@@ -259,6 +263,8 @@ class GcsRpcClient {
   std::unique_ptr<GrpcClient<StatsGcsService>> stats_grpc_client_;
   std::unique_ptr<GrpcClient<ErrorInfoGcsService>> error_info_grpc_client_;
   std::unique_ptr<GrpcClient<WorkerInfoGcsService>> worker_info_grpc_client_;
+  std::unique_ptr<GrpcClient<PlacementGroupInfoGcsService>>
+      placement_group_info_grpc_client_;
 };
 
 }  // namespace rpc

src/ray/rpc/gcs_server/gcs_rpc_server.h

@@ -44,6 +44,9 @@ namespace rpc {
 #define WORKER_INFO_SERVICE_RPC_HANDLER(HANDLER) \
   RPC_SERVICE_HANDLER(WorkerInfoGcsService, HANDLER)
 
+#define PLACEMENT_GROUP_INFO_SERVICE_RPC_HANDLER(HANDLER) \
+  RPC_SERVICE_HANDLER(PlacementGroupInfoGcsService, HANDLER)
+
 #define GCS_RPC_SEND_REPLY(send_reply_callback, reply, status) \
   reply->mutable_status()->set_code((int)status.code());       \
   reply->mutable_status()->set_message(status.message());      \
@@ -479,6 +482,41 @@ class WorkerInfoGrpcService : public GrpcService {
   WorkerInfoGcsServiceHandler &service_handler_;
 };
 
+class PlacementGroupInfoGcsServiceHandler {
+ public:
+  virtual ~PlacementGroupInfoGcsServiceHandler() = default;
+
+  virtual void HandleCreatePlacementGroup(const CreatePlacementGroupRequest &request,
+                                          CreatePlacementGroupReply *reply,
+                                          SendReplyCallback send_reply_callback) = 0;
+};
+
+/// The `GrpcService` for `PlacementGroupInfoGcsService`.
+class PlacementGroupInfoGrpcService : public GrpcService {
+ public:
+  /// Constructor.
+  ///
+  /// \param[in] handler The service handler that actually handle the requests.
+  explicit PlacementGroupInfoGrpcService(boost::asio::io_service &io_service,
+                                         PlacementGroupInfoGcsServiceHandler &handler)
+      : GrpcService(io_service), service_handler_(handler){};
+
+ protected:
+  grpc::Service &GetGrpcService() override { return service_; }
+
+  void InitServerCallFactories(
+      const std::unique_ptr<grpc::ServerCompletionQueue> &cq,
+      std::vector<std::unique_ptr<ServerCallFactory>> *server_call_factories) override {
+    PLACEMENT_GROUP_INFO_SERVICE_RPC_HANDLER(CreatePlacementGroup);
+  }
+
+ private:
+  /// The grpc async service object.
+  PlacementGroupInfoGcsService::AsyncService service_;
+  /// The service handler that actually handle the requests.
+  PlacementGroupInfoGcsServiceHandler &service_handler_;
+};
+
 using JobInfoHandler = JobInfoGcsServiceHandler;
 using ActorInfoHandler = ActorInfoGcsServiceHandler;
 using NodeInfoHandler = NodeInfoGcsServiceHandler;
@@ -487,6 +525,7 @@ using TaskInfoHandler = TaskInfoGcsServiceHandler;
 using StatsHandler = StatsGcsServiceHandler;
 using ErrorInfoHandler = ErrorInfoGcsServiceHandler;
 using WorkerInfoHandler = WorkerInfoGcsServiceHandler;
+using PlacementGroupInfoHandler = PlacementGroupInfoGcsServiceHandler;
 
 }  // namespace rpc
 }  // namespace ray