SERVER-67634 Ensure that change collections are never used on config

servers.

7 files changed, 19 insertions, 7 deletions

diff --git a/src/mongo/db/change_stream_change_collection_manager.cpp b/src/mongo/db/change_stream_change_collection_manager.cpp
index d085b514d18..5559e49390a 100644
--- a/src/mongo/db/change_stream_change_collection_manager.cpp
+++ b/src/mongo/db/change_stream_change_collection_manager.cpp
@@ -46,6 +46,7 @@
 #include "mongo/db/repl/apply_ops_command_info.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/oplog_entry_gen.h"
+#include "mongo/db/server_options.h"
 #include "mongo/logv2/log.h"
 
 namespace mongo {
@@ -200,6 +201,11 @@ void ChangeStreamChangeCollectionManager::create(ServiceContext* service) {
 }
 
 bool ChangeStreamChangeCollectionManager::isChangeCollectionsModeActive() {
+    // A change collection must not be enabled on the config server.
+    if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
+        return false;
+    }
+
     // If the force fail point is enabled then declare the change collection mode as active.
     if (MONGO_unlikely(forceEnableChangeCollectionsMode.shouldFail())) {
         return true;
diff --git a/src/mongo/db/change_stream_change_collection_manager.h b/src/mongo/db/change_stream_change_collection_manager.h
index cd2e166b1df..21a60c1bf0e 100644
--- a/src/mongo/db/change_stream_change_collection_manager.h
+++ b/src/mongo/db/change_stream_change_collection_manager.h
@@ -61,8 +61,8 @@ public:
     static ChangeStreamChangeCollectionManager& get(OperationContext* opCtx);
 
     /**
-     * Returns true if change collections are enabled for recording oplog entries, false
-     * otherwise.
+     * Returns true if the server is configured such that change collections can be used to record
+     * oplog entries; ie, we are running in a Serverless context. Returns false otherwise.
      */
     static bool isChangeCollectionsModeActive();
 
diff --git a/src/mongo/db/commands/run_aggregate.cpp b/src/mongo/db/commands/run_aggregate.cpp
index 981a692634e..acc2597af08 100644
--- a/src/mongo/db/commands/run_aggregate.cpp
+++ b/src/mongo/db/commands/run_aggregate.cpp
@@ -763,6 +763,12 @@ Status runAggregate(OperationContext* opCtx,
                 nss = NamespaceString::makeChangeCollectionNSS(origNss.tenantId());
             }
 
+            // Assert that a change stream on the config server is always opened on the oplog.
+            tassert(6763400,
+                    str::stream() << "Change stream was unexpectedly opened on the namespace: "
+                                  << nss << " in the config server",
+                    serverGlobalParams.clusterRole != ClusterRole::ConfigServer || nss.isOplog());
+
             // If the 'assertChangeStreamNssCollection' failpoint is active then ensure that we are
             // opening the change stream on the correct namespace.
             if (auto scopedFp = assertChangeStreamNssCollection.scoped();
diff --git a/src/mongo/db/repl/primary_only_service_util.h b/src/mongo/db/repl/primary_only_service_util.h
index 64aea0ac8d2..d94af7afc28 100644
--- a/src/mongo/db/repl/primary_only_service_util.h
+++ b/src/mongo/db/repl/primary_only_service_util.h
@@ -103,7 +103,7 @@ public:
     /**
      * The name of the 'PrimaryOnlyService::Instance'.
      */
-    virtual const StringData getInstanceName() = 0;
+    virtual StringData getInstanceName() = 0;
 
     /**
      * Interrupts the current running 'DefaultPrimaryOnlyServiceInstance' instance.
diff --git a/src/mongo/db/repl/primary_only_service_util_test.cpp b/src/mongo/db/repl/primary_only_service_util_test.cpp
index 0fc059d3d5a..6392ae9c67e 100644
--- a/src/mongo/db/repl/primary_only_service_util_test.cpp
+++ b/src/mongo/db/repl/primary_only_service_util_test.cpp
@@ -57,7 +57,7 @@ public:
         _state = state;
     }
 
-    const BSONObj toBSON() const {
+    BSONObj toBSON() const {
         return BSON("_id" << _state);
     }
 
@@ -74,7 +74,7 @@ PrimaryOnlyServiceStateStore<TestStateDocument> gStateDocStore{
  */
 class TestDefaultPrimaryOnlyServiceInstance : public DefaultPrimaryOnlyServiceInstance {
 public:
-    const StringData getInstanceName() final {
+    StringData getInstanceName() final {
         return kTestPrimaryOnlyServiceInstanceName;
     }
 
diff --git a/src/mongo/db/set_change_stream_state_coordinator.cpp b/src/mongo/db/set_change_stream_state_coordinator.cpp
index a172b2e06fc..a0ee72fac51 100644
--- a/src/mongo/db/set_change_stream_state_coordinator.cpp
+++ b/src/mongo/db/set_change_stream_state_coordinator.cpp
@@ -123,7 +123,7 @@ private:
 
 }  // namespace
 
-const StringData SetChangeStreamStateCoordinator::getInstanceName() {
+StringData SetChangeStreamStateCoordinator::getInstanceName() {
     return kSetChangeStreamStateCoordinatorName;
 }
 
diff --git a/src/mongo/db/set_change_stream_state_coordinator.h b/src/mongo/db/set_change_stream_state_coordinator.h
index aaa4d4305d6..7ca1592dc80 100644
--- a/src/mongo/db/set_change_stream_state_coordinator.h
+++ b/src/mongo/db/set_change_stream_state_coordinator.h
@@ -47,7 +47,7 @@ class SetChangeStreamStateCoordinator : public DefaultPrimaryOnlyServiceInstance
 public:
     explicit SetChangeStreamStateCoordinator(const BSONObj& stateDoc);
 
-    const StringData getInstanceName() final;
+    StringData getInstanceName() final;
 
     boost::optional<BSONObj> reportForCurrentOp(
         MongoProcessInterface::CurrentOpConnectionsMode connMode,