diff --git a/include/envoy/upstream/upstream.h b/include/envoy/upstream/upstream.h
index dbb89c88be670..139eb8ebb3a3f 100644
--- a/include/envoy/upstream/upstream.h
+++ b/include/envoy/upstream/upstream.h
@@ -789,6 +789,13 @@ class ClusterInfo {
   virtual const absl::optional<envoy::config::cluster::v3::Cluster::OriginalDstLbConfig>&
   lbOriginalDstConfig() const PURE;
 
+  /**
+   * @return const absl::optional<envoy::config::core::v3::TypedExtensionConfig>& the configuration
+   *         for the upstream, if a custom upstream is configured.
+   */
+  virtual const absl::optional<envoy::config::core::v3::TypedExtensionConfig>&
+  upstreamConfig() const PURE;
+
   /**
    * @return Whether the cluster is currently in maintenance mode and should not be routed to.
    *         Different filters may handle this situation in different ways. The implementation
diff --git a/source/common/router/router.cc b/source/common/router/router.cc
index 5ab68cc2d17ce..64f8450de4177 100644
--- a/source/common/router/router.cc
+++ b/source/common/router/router.cc
@@ -597,22 +597,20 @@ Http::FilterHeadersStatus Filter::decodeHeaders(Http::RequestHeaderMap& headers,
 }
 
 std::unique_ptr<GenericConnPool> Filter::createConnPool() {
+  GenericConnPoolFactory* factory = nullptr;
+  if (cluster_->upstreamConfig().has_value()) {
+    factory = &Envoy::Config::Utility::getAndCheckFactory<GenericConnPoolFactory>(
+        cluster_->upstreamConfig().value());
+  } else {
+    factory = &Envoy::Config::Utility::getAndCheckFactoryByName<GenericConnPoolFactory>(
+        "envoy.filters.connection_pools.http.generic");
+  }
   const bool should_tcp_proxy =
       route_entry_->connectConfig().has_value() &&
       downstream_headers_->getMethodValue() == Http::Headers::get().MethodValues.Connect;
   Http::Protocol protocol = cluster_->upstreamHttpProtocol(callbacks_->streamInfo().protocol());
-  if (should_tcp_proxy) {
-    auto pool = std::make_unique<TcpConnPool>(config_.cm_, *route_entry_, protocol, this);
-    if (pool->valid()) {
-      return pool;
-    }
-  } else {
-    auto pool = std::make_unique<HttpConnPool>(config_.cm_, *route_entry_, protocol, this);
-    if (pool->valid()) {
-      return pool;
-    }
-  }
-  return nullptr;
+  return factory->createGenericConnPool(config_.cm_, should_tcp_proxy, *route_entry_, protocol,
+                                        this);
 }
 
 void Filter::sendNoHealthyUpstreamResponse() {
diff --git a/source/common/upstream/upstream_impl.cc b/source/common/upstream/upstream_impl.cc
index a78a331cb9cc0..a11e06f2039e5 100644
--- a/source/common/upstream/upstream_impl.cc
+++ b/source/common/upstream/upstream_impl.cc
@@ -694,7 +694,12 @@ ClusterInfoImpl::ClusterInfoImpl(
       source_address_(getSourceAddress(config, bind_config)),
       lb_least_request_config_(config.least_request_lb_config()),
       lb_ring_hash_config_(config.ring_hash_lb_config()),
-      lb_original_dst_config_(config.original_dst_lb_config()), added_via_api_(added_via_api),
+      lb_original_dst_config_(config.original_dst_lb_config()),
+      upstream_config_(config.has_upstream_config()
+                           ? absl::make_optional<envoy::config::core::v3::TypedExtensionConfig>(
+                                 config.upstream_config())
+                           : absl::nullopt),
+      added_via_api_(added_via_api),
       lb_subset_(LoadBalancerSubsetInfoImpl(config.lb_subset_config())),
       metadata_(config.metadata()), typed_metadata_(config.metadata()),
       common_lb_config_(config.common_lb_config()),
diff --git a/source/common/upstream/upstream_impl.h b/source/common/upstream/upstream_impl.h
index 722aa5e5dcc33..372716d078949 100644
--- a/source/common/upstream/upstream_impl.h
+++ b/source/common/upstream/upstream_impl.h
@@ -565,6 +565,10 @@ class ClusterInfoImpl : public ClusterInfo, protected Logger::Loggable<Logger::I
   lbOriginalDstConfig() const override {
     return lb_original_dst_config_;
   }
+  const absl::optional<envoy::config::core::v3::TypedExtensionConfig>&
+  upstreamConfig() const override {
+    return upstream_config_;
+  }
   bool maintenanceMode() const override;
   uint64_t maxRequestsPerConnection() const override { return max_requests_per_connection_; }
   uint32_t maxResponseHeadersCount() const override { return max_response_headers_count_; }
@@ -645,6 +649,7 @@ class ClusterInfoImpl : public ClusterInfo, protected Logger::Loggable<Logger::I
       lb_least_request_config_;
   absl::optional<envoy::config::cluster::v3::Cluster::RingHashLbConfig> lb_ring_hash_config_;
   absl::optional<envoy::config::cluster::v3::Cluster::OriginalDstLbConfig> lb_original_dst_config_;
+  absl::optional<envoy::config::core::v3::TypedExtensionConfig> upstream_config_;
   const bool added_via_api_;
   LoadBalancerSubsetInfoImpl lb_subset_;
   const envoy::config::core::v3::Metadata metadata_;
diff --git a/source/extensions/upstreams/http/generic/BUILD b/source/extensions/upstreams/http/generic/BUILD
index 7aa32b16a2199..f61d9801103f6 100644
--- a/source/extensions/upstreams/http/generic/BUILD
+++ b/source/extensions/upstreams/http/generic/BUILD
@@ -1,5 +1,3 @@
-# placeholder build files for security_posture
-# Will be filled in as #11327 lands.
 load(
     "//bazel:envoy_build_system.bzl",
     "envoy_cc_extension",
@@ -13,8 +11,15 @@ envoy_package()
 envoy_cc_extension(
     name = "config",
     srcs = [
+        "config.cc",
     ],
     hdrs = [
+        "config.h",
     ],
     security_posture = "robust_to_untrusted_downstream",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//source/common/router:router_lib",
+        "@envoy_api//envoy/extensions/upstreams/http/generic/v3:pkg_cc_proto",
+    ],
 )
diff --git a/source/extensions/upstreams/http/generic/config.cc b/source/extensions/upstreams/http/generic/config.cc
new file mode 100644
index 0000000000000..f3057ccb8561d
--- /dev/null
+++ b/source/extensions/upstreams/http/generic/config.cc
@@ -0,0 +1,28 @@
+#include "extensions/upstreams/http/generic/config.h"
+
+#include "common/router/upstream_request.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Generic {
+
+Router::GenericConnPoolPtr GenericGenericConnPoolFactory::createGenericConnPool(
+    Upstream::ClusterManager& cm, bool is_connect, const Router::RouteEntry& route_entry,
+    Envoy::Http::Protocol protocol, Upstream::LoadBalancerContext* ctx) const {
+  if (is_connect) {
+    auto ret = std::make_unique<Router::TcpConnPool>(cm, route_entry, protocol, ctx);
+    return (ret->valid() ? std::move(ret) : nullptr);
+  }
+  auto ret = std::make_unique<Router::HttpConnPool>(cm, route_entry, protocol, ctx);
+  return (ret->valid() ? std::move(ret) : nullptr);
+}
+
+REGISTER_FACTORY(GenericGenericConnPoolFactory, Router::GenericConnPoolFactory);
+
+} // namespace Generic
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/extensions/upstreams/http/generic/config.h b/source/extensions/upstreams/http/generic/config.h
new file mode 100644
index 0000000000000..048e9998a4034
--- /dev/null
+++ b/source/extensions/upstreams/http/generic/config.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include "envoy/extensions/upstreams/http/generic/v3/generic_connection_pool.pb.h"
+#include "envoy/registry/registry.h"
+#include "envoy/router/router.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Generic {
+
+/**
+ * Config registration for the GenericConnPool. * @see Router::GenericConnPoolFactory
+ */
+class GenericGenericConnPoolFactory : public Router::GenericConnPoolFactory {
+public:
+  std::string name() const override { return "envoy.filters.connection_pools.http.generic"; }
+  std::string category() const override { return "envoy.upstreams"; }
+  Router::GenericConnPoolPtr
+  createGenericConnPool(Upstream::ClusterManager& cm, bool is_connect,
+                        const Router::RouteEntry& route_entry, Envoy::Http::Protocol protocol,
+                        Upstream::LoadBalancerContext* ctx) const override;
+
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override {
+    return std::make_unique<
+        envoy::extensions::upstreams::http::generic::v3::GenericConnectionPoolProto>();
+  }
+};
+
+DECLARE_FACTORY(GenericGenericConnPoolFactory);
+
+} // namespace Generic
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/extensions/upstreams/http/http/BUILD b/source/extensions/upstreams/http/http/BUILD
index 7aa32b16a2199..caf8f766e6f34 100644
--- a/source/extensions/upstreams/http/http/BUILD
+++ b/source/extensions/upstreams/http/http/BUILD
@@ -1,5 +1,3 @@
-# placeholder build files for security_posture
-# Will be filled in as #11327 lands.
 load(
     "//bazel:envoy_build_system.bzl",
     "envoy_cc_extension",
@@ -13,8 +11,15 @@ envoy_package()
 envoy_cc_extension(
     name = "config",
     srcs = [
+        "config.cc",
     ],
     hdrs = [
+        "config.h",
     ],
     security_posture = "robust_to_untrusted_downstream",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//source/common/router:router_lib",
+        "@envoy_api//envoy/extensions/upstreams/http/http/v3:pkg_cc_proto",
+    ],
 )
diff --git a/source/extensions/upstreams/http/http/config.cc b/source/extensions/upstreams/http/http/config.cc
new file mode 100644
index 0000000000000..a257b7e39b378
--- /dev/null
+++ b/source/extensions/upstreams/http/http/config.cc
@@ -0,0 +1,24 @@
+#include "extensions/upstreams/http/http/config.h"
+
+#include "common/router/upstream_request.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Http {
+
+Router::GenericConnPoolPtr HttpGenericConnPoolFactory::createGenericConnPool(
+    Upstream::ClusterManager& cm, bool, const Router::RouteEntry& route_entry,
+    Envoy::Http::Protocol protocol, Upstream::LoadBalancerContext* ctx) const {
+  auto ret = std::make_unique<Router::HttpConnPool>(cm, route_entry, protocol, ctx);
+  return (ret->valid() ? std::move(ret) : nullptr);
+}
+
+REGISTER_FACTORY(HttpGenericConnPoolFactory, Router::GenericConnPoolFactory);
+
+} // namespace Http
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/extensions/upstreams/http/http/config.h b/source/extensions/upstreams/http/http/config.h
new file mode 100644
index 0000000000000..9481f742a78d5
--- /dev/null
+++ b/source/extensions/upstreams/http/http/config.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include "envoy/extensions/upstreams/http/http/v3/http_connection_pool.pb.h"
+#include "envoy/registry/registry.h"
+#include "envoy/router/router.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Http {
+
+/**
+ * Config registration for the HttpConnPool. @see Router::GenericConnPoolFactory
+ */
+class HttpGenericConnPoolFactory : public Router::GenericConnPoolFactory {
+public:
+  std::string name() const override { return "envoy.filters.connection_pools.http.http"; }
+  std::string category() const override { return "envoy.upstreams"; }
+  Router::GenericConnPoolPtr
+  createGenericConnPool(Upstream::ClusterManager& cm, bool is_connect,
+                        const Router::RouteEntry& route_entry, Envoy::Http::Protocol protocol,
+                        Upstream::LoadBalancerContext* ctx) const override;
+
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override {
+    return std::make_unique<
+        envoy::extensions::upstreams::http::http::v3::HttpConnectionPoolProto>();
+  }
+};
+
+DECLARE_FACTORY(HttpGenericConnPoolFactory);
+
+} // namespace Http
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/extensions/upstreams/http/tcp/BUILD b/source/extensions/upstreams/http/tcp/BUILD
index 7aa32b16a2199..960f8b4b9c0d4 100644
--- a/source/extensions/upstreams/http/tcp/BUILD
+++ b/source/extensions/upstreams/http/tcp/BUILD
@@ -1,5 +1,3 @@
-# placeholder build files for security_posture
-# Will be filled in as #11327 lands.
 load(
     "//bazel:envoy_build_system.bzl",
     "envoy_cc_extension",
@@ -13,8 +11,15 @@ envoy_package()
 envoy_cc_extension(
     name = "config",
     srcs = [
+        "config.cc",
     ],
     hdrs = [
+        "config.h",
     ],
     security_posture = "robust_to_untrusted_downstream",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//source/common/router:router_lib",
+        "@envoy_api//envoy/extensions/upstreams/http/tcp/v3:pkg_cc_proto",
+    ],
 )
diff --git a/source/extensions/upstreams/http/tcp/config.cc b/source/extensions/upstreams/http/tcp/config.cc
new file mode 100644
index 0000000000000..ffd0412b643eb
--- /dev/null
+++ b/source/extensions/upstreams/http/tcp/config.cc
@@ -0,0 +1,24 @@
+#include "extensions/upstreams/http/tcp/config.h"
+
+#include "common/router/upstream_request.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Tcp {
+
+Router::GenericConnPoolPtr TcpGenericConnPoolFactory::createGenericConnPool(
+    Upstream::ClusterManager& cm, bool, const Router::RouteEntry& route_entry,
+    Envoy::Http::Protocol protocol, Upstream::LoadBalancerContext* ctx) const {
+  auto ret = std::make_unique<Router::TcpConnPool>(cm, route_entry, protocol, ctx);
+  return (ret->valid() ? std::move(ret) : nullptr);
+}
+
+REGISTER_FACTORY(TcpGenericConnPoolFactory, Router::GenericConnPoolFactory);
+
+} // namespace Tcp
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/extensions/upstreams/http/tcp/config.h b/source/extensions/upstreams/http/tcp/config.h
new file mode 100644
index 0000000000000..8fdaa9c31d033
--- /dev/null
+++ b/source/extensions/upstreams/http/tcp/config.h
@@ -0,0 +1,35 @@
+#pragma once
+
+#include "envoy/extensions/upstreams/http/tcp/v3/tcp_connection_pool.pb.h"
+#include "envoy/registry/registry.h"
+#include "envoy/router/router.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Upstreams {
+namespace Http {
+namespace Tcp {
+
+/**
+ * Config registration for the TcpConnPool. @see Router::GenericConnPoolFactory
+ */
+class TcpGenericConnPoolFactory : public Router::GenericConnPoolFactory {
+public:
+  std::string name() const override { return "envoy.filters.connection_pools.http.tcp"; }
+  std::string category() const override { return "envoy.upstreams"; }
+  Router::GenericConnPoolPtr
+  createGenericConnPool(Upstream::ClusterManager& cm, bool is_connect,
+                        const Router::RouteEntry& route_entry, Envoy::Http::Protocol protocol,
+                        Upstream::LoadBalancerContext* ctx) const override;
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override {
+    return std::make_unique<envoy::extensions::upstreams::http::tcp::v3::TcpConnectionPoolProto>();
+  }
+};
+
+DECLARE_FACTORY(TcpGenericConnPoolFactory);
+
+} // namespace Tcp
+} // namespace Http
+} // namespace Upstreams
+} // namespace Extensions
+} // namespace Envoy
diff --git a/source/server/BUILD b/source/server/BUILD
index e927018621887..b1d5ce852b964 100644
--- a/source/server/BUILD
+++ b/source/server/BUILD
@@ -79,6 +79,9 @@ envoy_cc_library(
         "//source/common/stats:timespan_lib",
         "//source/common/stream_info:stream_info_lib",
         "//source/extensions/transport_sockets:well_known_names",
+        "//source/extensions/upstreams/http/generic:config",
+        "//source/extensions/upstreams/http/http:config",
+        "//source/extensions/upstreams/http/tcp:config",
     ],
 )
 
diff --git a/test/common/http/BUILD b/test/common/http/BUILD
index 5a42fb54f59bc..e723a48abeb01 100644
--- a/test/common/http/BUILD
+++ b/test/common/http/BUILD
@@ -23,6 +23,7 @@ envoy_cc_test(
         "//source/common/http:context_lib",
         "//source/common/http:headers_lib",
         "//source/common/http:utility_lib",
+        "//source/extensions/upstreams/http/generic:config",
         "//test/mocks:common_lib",
         "//test/mocks/buffer:buffer_mocks",
         "//test/mocks/http:http_mocks",
diff --git a/test/common/router/BUILD b/test/common/router/BUILD
index d1c5b7c036ed1..81a4b7e7a63b9 100644
--- a/test/common/router/BUILD
+++ b/test/common/router/BUILD
@@ -262,6 +262,9 @@ envoy_cc_test(
         "//source/common/stream_info:uint32_accessor_lib",
         "//source/common/upstream:upstream_includes",
         "//source/common/upstream:upstream_lib",
+        "//source/extensions/upstreams/http/generic:config",
+        "//source/extensions/upstreams/http/http:config",
+        "//source/extensions/upstreams/http/tcp:config",
         "//test/common/http:common_lib",
         "//test/mocks/http:http_mocks",
         "//test/mocks/local_info:local_info_mocks",
@@ -276,6 +279,8 @@ envoy_cc_test(
         "//test/test_common:utility_lib",
         "@envoy_api//envoy/config/core/v3:pkg_cc_proto",
         "@envoy_api//envoy/extensions/transport_sockets/tls/v3:pkg_cc_proto",
+        "@envoy_api//envoy/extensions/upstreams/http/http/v3:pkg_cc_proto",
+        "@envoy_api//envoy/extensions/upstreams/http/tcp/v3:pkg_cc_proto",
         "@envoy_api//envoy/type/v3:pkg_cc_proto",
     ],
 )
@@ -292,6 +297,7 @@ envoy_cc_test(
         "//source/common/upstream:upstream_includes",
         "//source/common/upstream:upstream_lib",
         "//source/extensions/access_loggers/file:config",
+        "//source/extensions/upstreams/http/generic:config",
         "//test/common/http:common_lib",
         "//test/mocks/access_log:access_log_mocks",
         "//test/mocks/filesystem:filesystem_mocks",
diff --git a/test/common/router/router_test.cc b/test/common/router/router_test.cc
index 6b9137e723ca8..eaf43fc2be4f7 100644
--- a/test/common/router/router_test.cc
+++ b/test/common/router/router_test.cc
@@ -5,6 +5,8 @@
 
 #include "envoy/config/core/v3/base.pb.h"
 #include "envoy/extensions/transport_sockets/tls/v3/cert.pb.h"
+#include "envoy/extensions/upstreams/http/http/v3/http_connection_pool.pb.h"
+#include "envoy/extensions/upstreams/http/tcp/v3/tcp_connection_pool.pb.h"
 #include "envoy/type/v3/percent.pb.h"
 
 #include "common/buffer/buffer_impl.h"
@@ -5932,6 +5934,14 @@ TEST_F(RouterTest, ConnectPauseAndResume) {
 
 // Verify that CONNECT payload is not sent upstream if non-200 response headers are received.
 TEST_F(RouterTest, ConnectPauseNoResume) {
+  // Explicitly configure an HTTP upstream, to test factory creation.
+  cm_.thread_local_cluster_.cluster_.info_->upstream_config_ =
+      absl::make_optional<envoy::config::core::v3::TypedExtensionConfig>();
+  envoy::extensions::upstreams::http::http::v3::HttpConnectionPoolProto http_config;
+  cm_.thread_local_cluster_.cluster_.info_->upstream_config_.value()
+      .mutable_typed_config()
+      ->PackFrom(http_config);
+
   NiceMock<Http::MockRequestEncoder> encoder;
   Http::ResponseDecoder* response_decoder = nullptr;
   EXPECT_CALL(cm_.conn_pool_, newStream(_, _))
@@ -5962,6 +5972,27 @@ TEST_F(RouterTest, ConnectPauseNoResume) {
   response_decoder->decodeHeaders(std::move(response_headers), true);
 }
 
+TEST_F(RouterTest, ConnectExplicitTcpUpstream) {
+  // Explicitly configure an TCP upstream, to test factory creation.
+  cm_.thread_local_cluster_.cluster_.info_->upstream_config_ =
+      absl::make_optional<envoy::config::core::v3::TypedExtensionConfig>();
+  envoy::extensions::upstreams::http::tcp::v3::TcpConnectionPoolProto tcp_config;
+  cm_.thread_local_cluster_.cluster_.info_->upstream_config_.value()
+      .mutable_typed_config()
+      ->PackFrom(tcp_config);
+  callbacks_.route_->route_entry_.connect_config_ =
+      absl::make_optional<RouteEntry::ConnectConfig>();
+
+  // Make sure newConnection is called on the TCP pool, not newStream on the HTTP pool.
+  EXPECT_CALL(cm_.tcp_conn_pool_, newConnection(_));
+  Http::TestRequestHeaderMapImpl headers;
+  HttpTestUtility::addDefaultHeaders(headers);
+  headers.setMethod("CONNECT");
+  router_.decodeHeaders(headers, false);
+
+  router_.onDestroy();
+}
+
 class WatermarkTest : public RouterTest {
 public:
   void sendRequest(bool header_only_request = true, bool pool_ready = true) {
diff --git a/test/integration/stats_integration_test.cc b/test/integration/stats_integration_test.cc
index 40d65003dd32f..15d060d6d4a0c 100644
--- a/test/integration/stats_integration_test.cc
+++ b/test/integration/stats_integration_test.cc
@@ -272,6 +272,7 @@ TEST_P(ClusterMemoryTestRunner, MemoryLargeClusterSizeWithFakeSymbolTable) {
   // 2020/05/05  10908    44233       44600   router: add InternalRedirectPolicy and predicate
   // 2020/05/13  10531    44425       44600   Refactor resource manager
   // 2020/05/20  11223    44491       44600   Add primary clusters tracking to cluster manager.
+  // 2020/06/10  11561    44491       44811   Make upstreams pluggable
 
   // Note: when adjusting this value: EXPECT_MEMORY_EQ is active only in CI
   // 'release' builds, where we control the platform and tool-chain. So you
@@ -286,7 +287,7 @@ TEST_P(ClusterMemoryTestRunner, MemoryLargeClusterSizeWithFakeSymbolTable) {
   // https://github.com/envoyproxy/envoy/blob/master/source/docs/stats.md#stats-memory-tests
   // for details on how to fix.
   EXPECT_MEMORY_EQ(m_per_cluster, 44491);
-  EXPECT_MEMORY_LE(m_per_cluster, 44600);
+  EXPECT_MEMORY_LE(m_per_cluster, 44811);
 }
 
 TEST_P(ClusterMemoryTestRunner, MemoryLargeClusterSizeWithRealSymbolTable) {
@@ -334,6 +335,7 @@ TEST_P(ClusterMemoryTestRunner, MemoryLargeClusterSizeWithRealSymbolTable) {
   // 2020/05/05  10908    36345       36800   router: add InternalRedirectPolicy and predicate
   // 2020/05/13  10531    36537       36800   Refactor resource manager
   // 2020/05/20  11223    36603       36800   Add primary clusters tracking to cluster manager.
+  // 2020/06/10  11561    36603       36923   Make upstreams pluggable
 
   // Note: when adjusting this value: EXPECT_MEMORY_EQ is active only in CI
   // 'release' builds, where we control the platform and tool-chain. So you
@@ -348,7 +350,7 @@ TEST_P(ClusterMemoryTestRunner, MemoryLargeClusterSizeWithRealSymbolTable) {
   // https://github.com/envoyproxy/envoy/blob/master/source/docs/stats.md#stats-memory-tests
   // for details on how to fix.
   EXPECT_MEMORY_EQ(m_per_cluster, 36603);
-  EXPECT_MEMORY_LE(m_per_cluster, 36800);
+  EXPECT_MEMORY_LE(m_per_cluster, 36923);
 }
 
 TEST_P(ClusterMemoryTestRunner, MemoryLargeHostSizeWithStats) {
diff --git a/test/mocks/upstream/cluster_info.cc b/test/mocks/upstream/cluster_info.cc
index dd428aa124c28..3a2c1aa8af8df 100644
--- a/test/mocks/upstream/cluster_info.cc
+++ b/test/mocks/upstream/cluster_info.cc
@@ -81,6 +81,7 @@ MockClusterInfo::MockClusterInfo()
   ON_CALL(*this, lbSubsetInfo()).WillByDefault(ReturnRef(lb_subset_));
   ON_CALL(*this, lbRingHashConfig()).WillByDefault(ReturnRef(lb_ring_hash_config_));
   ON_CALL(*this, lbOriginalDstConfig()).WillByDefault(ReturnRef(lb_original_dst_config_));
+  ON_CALL(*this, upstreamConfig()).WillByDefault(ReturnRef(upstream_config_));
   ON_CALL(*this, lbConfig()).WillByDefault(ReturnRef(lb_config_));
   ON_CALL(*this, clusterSocketOptions()).WillByDefault(ReturnRef(cluster_socket_options_));
   ON_CALL(*this, metadata()).WillByDefault(ReturnRef(metadata_));
diff --git a/test/mocks/upstream/cluster_info.h b/test/mocks/upstream/cluster_info.h
index 2e99eea091ef9..e3bce01c62826 100644
--- a/test/mocks/upstream/cluster_info.h
+++ b/test/mocks/upstream/cluster_info.h
@@ -108,6 +108,8 @@ class MockClusterInfo : public ClusterInfo {
               lbLeastRequestConfig, (), (const));
   MOCK_METHOD(const absl::optional<envoy::config::cluster::v3::Cluster::OriginalDstLbConfig>&,
               lbOriginalDstConfig, (), (const));
+  MOCK_METHOD(const absl::optional<envoy::config::core::v3::TypedExtensionConfig>&, upstreamConfig,
+              (), (const));
   MOCK_METHOD(bool, maintenanceMode, (), (const));
   MOCK_METHOD(uint32_t, maxResponseHeadersCount, (), (const));
   MOCK_METHOD(uint64_t, maxRequestsPerConnection, (), (const));
@@ -163,6 +165,7 @@ class MockClusterInfo : public ClusterInfo {
       upstream_http_protocol_options_;
   absl::optional<envoy::config::cluster::v3::Cluster::RingHashLbConfig> lb_ring_hash_config_;
   absl::optional<envoy::config::cluster::v3::Cluster::OriginalDstLbConfig> lb_original_dst_config_;
+  absl::optional<envoy::config::core::v3::TypedExtensionConfig> upstream_config_;
   Network::ConnectionSocket::OptionsSharedPtr cluster_socket_options_;
   envoy::config::cluster::v3::Cluster::CommonLbConfig lb_config_;
   envoy::config::core::v3::Metadata metadata_;