diff --git a/plugin/federated/federated_comm.h b/plugin/federated/federated_comm.h
index d847d8655aa0..b39e1878a8ea 100644
--- a/plugin/federated/federated_comm.h
+++ b/plugin/federated/federated_comm.h
@@ -50,6 +50,10 @@ class FederatedComm : public HostComm {
                          std::int32_t rank) {
     this->Init(host, port, world, rank, {}, {}, {});
   }
+  [[nodiscard]] Result Shutdown() final {
+    this->ResetState();
+    return Success();
+  }
   ~FederatedComm() override { stub_.reset(); }
 
   [[nodiscard]] std::shared_ptr<Channel> Chan(std::int32_t) const override {
diff --git a/src/collective/comm.cc b/src/collective/comm.cc
index bc8cf61d96d9..088f845510d7 100644
--- a/src/collective/comm.cc
+++ b/src/collective/comm.cc
@@ -22,11 +22,7 @@
 namespace xgboost::collective {
 Comm::Comm(std::string const& host, std::int32_t port, std::chrono::seconds timeout,
            std::int32_t retry, std::string task_id)
-    : timeout_{timeout},
-      retry_{retry},
-      tracker_{host, port, -1},
-      task_id_{std::move(task_id)},
-      loop_{std::shared_ptr<Loop>{new Loop{timeout}}} {}
+    : timeout_{timeout}, retry_{retry}, tracker_{host, port, -1}, task_id_{std::move(task_id)} {}
 
 Result ConnectTrackerImpl(proto::PeerInfo info, std::chrono::seconds timeout, std::int32_t retry,
                           std::string const& task_id, TCPSocket* out, std::int32_t rank,
@@ -192,6 +188,7 @@ RabitComm::RabitComm(std::string const& host, std::int32_t port, std::chrono::se
                      std::int32_t retry, std::string task_id, StringView nccl_path)
     : HostComm{std::move(host), port, timeout, retry, std::move(task_id)},
       nccl_path_{std::move(nccl_path)} {
+  loop_.reset(new Loop{std::chrono::seconds{timeout_}});  // NOLINT
   auto rc = this->Bootstrap(timeout_, retry_, task_id_);
   if (!rc.OK()) {
     SafeColl(Fail("Failed to bootstrap the communication group.", std::move(rc)));
@@ -309,6 +306,11 @@ RabitComm::~RabitComm() noexcept(false) {
     if (n_bytes != scmd.size()) {
       return Fail("Faled to send cmd.");
     }
+
+    this->ResetState();
+    return Success();
+  } << [&] {
+    this->channels_.clear();
     return Success();
   };
 }
diff --git a/src/collective/comm.cuh b/src/collective/comm.cuh
index a818d95f8134..4add9ca612e0 100644
--- a/src/collective/comm.cuh
+++ b/src/collective/comm.cuh
@@ -50,6 +50,10 @@ class NCCLComm : public Comm {
     auto rc = this->Stream().Sync(false);
     return GetCUDAResult(rc);
   }
+  [[nodiscard]] Result Shutdown() final {
+    this->ResetState();
+    return Success();
+  }
 };
 
 class NCCLChannel : public Channel {
diff --git a/src/collective/comm.h b/src/collective/comm.h
index 4b948beb027e..6ad5bc5c1a6f 100644
--- a/src/collective/comm.h
+++ b/src/collective/comm.h
@@ -54,8 +54,12 @@ class Comm : public std::enable_shared_from_this<Comm> {
   std::thread error_worker_;
   std::string task_id_;
   std::vector<std::shared_ptr<Channel>> channels_;
-  std::shared_ptr<Loop> loop_{new Loop{std::chrono::seconds{
-      DefaultTimeoutSec()}}};  // fixme: require federated comm to have a timeout
+  std::shared_ptr<Loop> loop_{nullptr};  // fixme: require federated comm to have a timeout
+
+  void ResetState() {
+    this->world_ = -1;
+    this->rank_ = 0;
+  }
 
  public:
   Comm() = default;
@@ -78,7 +82,10 @@ class Comm : public std::enable_shared_from_this<Comm> {
   [[nodiscard]] auto Rank() const { return rank_; }
   [[nodiscard]] auto World() const { return IsDistributed() ? world_ : 1; }
   [[nodiscard]] bool IsDistributed() const { return world_ != -1; }
-  void Submit(Loop::Op op) const { loop_->Submit(op); }
+  void Submit(Loop::Op op) const {
+    CHECK(loop_);
+    loop_->Submit(op);
+  }
   [[nodiscard]] virtual Result Block() const { return loop_->Block(); }
 
   [[nodiscard]] virtual std::shared_ptr<Channel> Chan(std::int32_t rank) const {
@@ -95,6 +102,7 @@ class Comm : public std::enable_shared_from_this<Comm> {
     auto rc = GetHostName(out);
     return rc;
   }
+  [[nodiscard]] virtual Result Shutdown() = 0;
 };
 
 /**
@@ -112,7 +120,7 @@ class RabitComm : public HostComm {
 
   [[nodiscard]] Result Bootstrap(std::chrono::seconds timeout, std::int32_t retry,
                                  std::string task_id);
-  [[nodiscard]] Result Shutdown();
+  [[nodiscard]] Result Shutdown() final;
 
  public:
   // bootstrapping construction.
diff --git a/src/collective/comm_group.cc b/src/collective/comm_group.cc
index 2936a14914ec..7408882f6d2a 100644
--- a/src/collective/comm_group.cc
+++ b/src/collective/comm_group.cc
@@ -116,6 +116,8 @@ void GlobalCommGroupInit(Json config) {
 
 void GlobalCommGroupFinalize() {
   auto& sptr = GlobalCommGroup();
+  auto rc = sptr->Finalize();
   sptr.reset();
+  SafeColl(rc);
 }
 }  // namespace xgboost::collective
diff --git a/src/collective/comm_group.h b/src/collective/comm_group.h
index 1f403ae6b592..61a58ba56bed 100644
--- a/src/collective/comm_group.h
+++ b/src/collective/comm_group.h
@@ -34,6 +34,17 @@ class CommGroup {
   [[nodiscard]] auto Rank() const { return comm_->Rank(); }
   [[nodiscard]] bool IsDistributed() const { return comm_->IsDistributed(); }
 
+  [[nodiscard]] Result Finalize() const {
+    return Success() << [this] {
+      if (gpu_comm_) {
+        return gpu_comm_->Shutdown();
+      }
+      return Success();
+    } << [&] {
+      return comm_->Shutdown();
+    };
+  }
+
   [[nodiscard]] static CommGroup* Create(Json config);
 
   [[nodiscard]] std::shared_ptr<Coll> Backend(DeviceOrd device) const;
diff --git a/src/collective/loop.cc b/src/collective/loop.cc
index b51749fcdad5..cd4859f333a8 100644
--- a/src/collective/loop.cc
+++ b/src/collective/loop.cc
@@ -243,6 +243,16 @@ Result Loop::Stop() {
   }
 }
 
+void Loop::Submit(Op op) {
+  std::unique_lock lock{mu_};
+  if (op.code != Op::kBlock) {
+    CHECK_NE(op.n, 0);
+  }
+  queue_.push(op);
+  lock.unlock();
+  cv_.notify_one();
+}
+
 Loop::Loop(std::chrono::seconds timeout) : timeout_{timeout} {
   timer_.Init(__func__);
   worker_ = std::thread{[this] { this->Process(); }};
diff --git a/src/collective/loop.h b/src/collective/loop.h
index 5e9f38c2933f..5405f6b13e1d 100644
--- a/src/collective/loop.h
+++ b/src/collective/loop.h
@@ -64,15 +64,7 @@ class Loop {
    */
   Result Stop();
 
-  void Submit(Op op) {
-    std::unique_lock lock{mu_};
-    if (op.code != Op::kBlock) {
-      CHECK_NE(op.n, 0);
-    }
-    queue_.push(op);
-    lock.unlock();
-    cv_.notify_one();
-  }
+  void Submit(Op op);
 
   /**
    * @brief Block the event loop until all ops are finished. In the case of failure, this