diff --git a/tests/base.py b/tests/base.py
index da7b665385..233621f3d9 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -93,7 +93,7 @@ from zuul.driver.elasticsearch import ElasticsearchDriver
 from zuul.lib.collections import DefaultKeyDict
 from zuul.lib.connections import ConnectionRegistry
 from zuul.zk import zkobject, ZooKeeperClient
-from zuul.zk.components import SchedulerComponent
+from zuul.zk.components import SchedulerComponent, COMPONENT_REGISTRY
 from zuul.zk.event_queues import ConnectionEventQueue
 from zuul.zk.executor import ExecutorApi
 from zuul.zk.locks import tenant_read_lock, pipeline_lock, SessionAwareLock
@@ -4032,6 +4032,15 @@ class PrometheusFixture(fixtures.Fixture):
                 prometheus_client.registry.REGISTRY.unregister(collector)
 
 
+class GlobalRegistryFixture(fixtures.Fixture):
+    def _setUp(self):
+        self.addCleanup(self._cleanup)
+
+    def _cleanup(self):
+        # Remove our component registry from the global
+        COMPONENT_REGISTRY.clearRegistry()
+
+
 class FakeCPUTimes:
     def __init__(self):
         self.user = 0
@@ -4072,6 +4081,7 @@ class BaseTestCase(testtools.TestCase):
     def setUp(self):
         super(BaseTestCase, self).setUp()
         self.useFixture(PrometheusFixture())
+        self.useFixture(GlobalRegistryFixture())
         test_timeout = os.environ.get('OS_TEST_TIMEOUT', 0)
         try:
             test_timeout = int(test_timeout)
@@ -4600,8 +4610,7 @@ class ZuulTestCase(BaseTestCase):
             self._context_lock.acquire(blocking=False)
             lock = self._context_lock
         return zkobject.ZKContext(self.zk_client, lock,
-                                  None, self.log,
-                                  self.scheds.first.sched.component_registry)
+                                  None, self.log)
 
     def __event_queues(self, matcher) -> List[Queue]:
         # TODO (swestphahl): Can be removed when we no longer use global
diff --git a/tests/unit/test_model_upgrade.py b/tests/unit/test_model_upgrade.py
index 2a8db82dcb..a0d726e4b8 100644
--- a/tests/unit/test_model_upgrade.py
+++ b/tests/unit/test_model_upgrade.py
@@ -119,6 +119,7 @@ class TestSemaphoreModelUpgrade(ZuulTestCase):
 
         semaphore_holders = tenant.semaphore_handler.semaphoreHolders(
             "test-semaphore")
+        self.log.debug("Semaphore holders: %s", repr(semaphore_holders))
         self.assertEqual(len(semaphore_holders), 1)
         # Assert that we are still using the old-style handler format
         self.assertTrue(all(isinstance(h, str) for h in semaphore_holders))
@@ -177,6 +178,7 @@ class TestSemaphoreModelUpgrade(ZuulTestCase):
         tenant.semaphore_handler.acquire(item, job, False)
         semaphore_holders = tenant.semaphore_handler.semaphoreHolders(
             "test-semaphore")
+        self.log.debug("Semaphore holders: %s", repr(semaphore_holders))
         self.assertEqual(len(semaphore_holders), 1)
         # Assert that we are now using the new-style handler format
         self.assertTrue(all(isinstance(h, dict) for h in semaphore_holders))
diff --git a/tests/unit/test_zk.py b/tests/unit/test_zk.py
index b3237072ec..9da8218cda 100644
--- a/tests/unit/test_zk.py
+++ b/tests/unit/test_zk.py
@@ -1505,8 +1505,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
         # Create a new object
         tenant_name = 'fake_tenant'
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             pipeline1 = zkobject_class.new(context,
                                            name=tenant_name,
                                            foo='bar')
@@ -1517,8 +1516,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
         # Load an object from ZK (that we don't already have)
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             pipeline2 = zkobject_class.fromZK(context,
                                               '/zuul/pipeline/fake_tenant')
             self.assertEqual(pipeline2.foo, 'bar')
@@ -1532,8 +1530,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
         # Update an object
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             ltime1 = get_ltime(pipeline1)
             pipeline1.updateAttributes(context, foo='qux')
             self.assertEqual(pipeline1.foo, 'qux')
@@ -1547,8 +1544,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
         # Update an object using an active context
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             ltime1 = get_ltime(pipeline1)
             with pipeline1.activeContext(context):
                 pipeline1.foo = 'baz'
@@ -1569,15 +1565,13 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
         # Refresh an existing object
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             pipeline2.refresh(context)
             self.assertEqual(pipeline2.foo, 'baz')
 
         # Delete an object
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             self.assertIsNotNone(self.zk_client.client.exists(
                 '/zuul/pipeline/fake_tenant'))
             pipeline2.delete(context)
@@ -1620,8 +1614,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
         # Fail an update
         with tenant_write_lock(self.zk_client, tenant_name) as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             pipeline1 = zkobject_class.new(context,
                                            name=tenant_name,
                                            foo='one')
@@ -1815,8 +1808,7 @@ class TestConfigurationErrorList(ZooKeeperBaseTestCase):
 
         # Create a new object
         with tenant_write_lock(self.zk_client, 'test') as lock:
-            context = ZKContext(self.zk_client, lock, stop_event, self.log,
-                                self.component_registry)
+            context = ZKContext(self.zk_client, lock, stop_event, self.log)
             pipeline = DummyZKObject.new(context, name="test", foo="bar")
             e1 = model.ConfigurationError(
                 source_context, start_mark, "Test error1")
diff --git a/zuul/cmd/client.py b/zuul/cmd/client.py
index dc8d4772c2..fc1ea6a2ea 100755
--- a/zuul/cmd/client.py
+++ b/zuul/cmd/client.py
@@ -37,7 +37,7 @@ from zuul.lib.keystorage import KeyStorage
 from zuul.zk.locks import tenant_write_lock
 from zuul.zk.zkobject import ZKContext
 from zuul.zk.layout import LayoutState, LayoutStateStore
-from zuul.zk.components import ComponentRegistry
+from zuul.zk.components import COMPONENT_REGISTRY
 
 
 # todo This should probably live somewhere else
@@ -963,15 +963,14 @@ class Client(zuul.cmd.ZuulApp):
         args = self.args
         safe_tenant = urllib.parse.quote_plus(args.tenant)
         safe_pipeline = urllib.parse.quote_plus(args.pipeline)
-        component_registry = ComponentRegistry(zk_client)
+        COMPONENT_REGISTRY.create(zk_client)
         with tenant_write_lock(zk_client, args.tenant) as lock:
             path = f'/zuul/tenant/{safe_tenant}/pipeline/{safe_pipeline}'
             layout_uuid = None
             zk_client.client.delete(
                 f'/zuul/tenant/{safe_tenant}/pipeline/{safe_pipeline}',
                 recursive=True)
-            context = ZKContext(zk_client, lock, None, self.log,
-                                component_registry)
+            context = ZKContext(zk_client, lock, None, self.log)
             ps = PipelineState.new(context, _path=path,
                                    layout_uuid=layout_uuid)
             # Force everyone to make a new layout for this tenant in
diff --git a/zuul/configloader.py b/zuul/configloader.py
index 7ed296d837..d5adf0542a 100644
--- a/zuul/configloader.py
+++ b/zuul/configloader.py
@@ -1640,8 +1640,7 @@ class TenantParser(object):
             tenant, parsed_config, loading_errors, layout_uuid)
         if self.scheduler:
             tenant.semaphore_handler = SemaphoreHandler(
-                self.zk_client, self.statsd, tenant.name, tenant.layout,
-                self.scheduler.component_registry
+                self.zk_client, self.statsd, tenant.name, tenant.layout
             )
 
         return tenant
diff --git a/zuul/executor/server.py b/zuul/executor/server.py
index 3330e96415..acb2e3cc71 100644
--- a/zuul/executor/server.py
+++ b/zuul/executor/server.py
@@ -72,7 +72,7 @@ import zuul.model
 from zuul.nodepool import Nodepool
 from zuul.version import get_version_string
 from zuul.zk.event_queues import PipelineResultEventQueue
-from zuul.zk.components import ExecutorComponent, ComponentRegistry
+from zuul.zk.components import ExecutorComponent, COMPONENT_REGISTRY
 from zuul.zk.exceptions import JobRequestNotFound
 from zuul.zk.executor import ExecutorApi
 from zuul.zk.job_request_queue import JobRequestEvent
@@ -3195,9 +3195,8 @@ class ExecutorServer(BaseMergeServer):
         self.component_info = ExecutorComponent(
             self.zk_client, self.hostname, version=get_version_string())
         self.component_info.register()
-        self.component_registry = ComponentRegistry(self.zk_client)
-        self.zk_context = ZKContext(self.zk_client, None, None, self.log,
-                                    self.component_registry)
+        COMPONENT_REGISTRY.create(self.zk_client)
+        self.zk_context = ZKContext(self.zk_client, None, None, self.log)
         self.monitoring_server = MonitoringServer(self.config, 'executor',
                                                   self.component_info)
         self.monitoring_server.start()
diff --git a/zuul/lib/fingergw.py b/zuul/lib/fingergw.py
index dd2218b262..90eb032ea5 100644
--- a/zuul/lib/fingergw.py
+++ b/zuul/lib/fingergw.py
@@ -28,7 +28,7 @@ from zuul.lib.config import get_default
 from zuul.lib.monitoring import MonitoringServer
 from zuul.version import get_version_string
 from zuul.zk import ZooKeeperClient
-from zuul.zk.components import ComponentRegistry, FingerGatewayComponent
+from zuul.zk.components import COMPONENT_REGISTRY, FingerGatewayComponent
 from zuul.zk.executor import ExecutorApi
 
 COMMANDS = [
@@ -88,7 +88,7 @@ class RequestHandler(streamer_utils.BaseFingerRequestHandler):
         try:
             build_uuid = self.getCommand()
             port_location = streamer_utils.getJobLogStreamAddress(
-                self.fingergw.executor_api, self.fingergw.component_registry,
+                self.fingergw.executor_api,
                 build_uuid, source_zone=self.fingergw.zone)
 
             if not port_location:
@@ -190,13 +190,12 @@ class FingerGateway(object):
         if self.tls_listen:
             self.component_info.use_ssl = True
         self.component_info.register()
+        COMPONENT_REGISTRY.create(self.zk_client)
 
         self.monitoring_server = MonitoringServer(config, 'fingergw',
                                                   self.component_info)
         self.monitoring_server.start()
 
-        self.component_registry = ComponentRegistry(self.zk_client)
-
         self.executor_api = ExecutorApi(self.zk_client, use_cache=False)
 
     def _runCommand(self):
diff --git a/zuul/lib/streamer_utils.py b/zuul/lib/streamer_utils.py
index 1882dd64a1..5ebdcc6b86 100644
--- a/zuul/lib/streamer_utils.py
+++ b/zuul/lib/streamer_utils.py
@@ -30,6 +30,7 @@ import threading
 import time
 
 from zuul.exceptions import StreamingError
+from zuul.zk.components import COMPONENT_REGISTRY
 
 
 log = logging.getLogger("zuul.lib.streamer_utils")
@@ -175,8 +176,7 @@ class CustomThreadingTCPServer(socketserver.ThreadingTCPServer):
         return sock, addr
 
 
-def getJobLogStreamAddress(executor_api, component_registry, uuid,
-                           source_zone):
+def getJobLogStreamAddress(executor_api, uuid, source_zone):
     """
     Looks up the log stream address for the given build UUID.
 
@@ -199,7 +199,7 @@ def getJobLogStreamAddress(executor_api, component_registry, uuid,
 
     job_log_stream_address = {}
     if worker_zone and source_zone != worker_zone:
-        info = _getFingerGatewayInZone(component_registry, worker_zone)
+        info = _getFingerGatewayInZone(worker_zone)
         if info:
             job_log_stream_address['server'] = info.hostname
             job_log_stream_address['port'] = info.public_port
@@ -225,8 +225,9 @@ def getJobLogStreamAddress(executor_api, component_registry, uuid,
     return job_log_stream_address
 
 
-def _getFingerGatewayInZone(component_registry, zone):
-    gws = [gw for gw in component_registry.all('fingergw') if gw.zone == zone]
+def _getFingerGatewayInZone(zone):
+    registry = COMPONENT_REGISTRY.registry
+    gws = [gw for gw in registry.all('fingergw') if gw.zone == zone]
     if gws:
         return random.choice(gws)
     return None
diff --git a/zuul/manager/__init__.py b/zuul/manager/__init__.py
index b0677e4c33..070065ba1f 100644
--- a/zuul/manager/__init__.py
+++ b/zuul/manager/__init__.py
@@ -26,6 +26,7 @@ from zuul.model import (
     Change, DequeueEvent, PipelineState, PipelineChangeList, QueueItem,
 )
 from zuul.zk.change_cache import ChangeKey
+from zuul.zk.components import COMPONENT_REGISTRY
 from zuul.zk.locks import pipeline_lock
 
 
@@ -731,7 +732,7 @@ class PipelineManager(metaclass=ABCMeta):
                 continue
 
             # MODEL_API: >2
-            if self.sched.component_registry.model_api > 2:
+            if COMPONENT_REGISTRY.model_api > 2:
                 event = model.SupercedeEvent(
                     other_pipeline.tenant.name,
                     other_pipeline.name,
diff --git a/zuul/scheduler.py b/zuul/scheduler.py
index e7cd3c0eff..7f204616aa 100644
--- a/zuul/scheduler.py
+++ b/zuul/scheduler.py
@@ -81,7 +81,7 @@ from zuul.zk.cleanup import (
     NodeRequestCleanupLock,
 )
 from zuul.zk.components import (
-    BaseComponent, ComponentRegistry, SchedulerComponent
+    BaseComponent, COMPONENT_REGISTRY, SchedulerComponent
 )
 from zuul.zk.config_cache import SystemConfigCache, UnparsedConfigCache
 from zuul.zk.event_queues import (
@@ -236,7 +236,7 @@ class Scheduler(threading.Thread):
         self.component_info = SchedulerComponent(
             self.zk_client, self.hostname, version=self.zuul_version)
         self.component_info.register()
-        self.component_registry = ComponentRegistry(self.zk_client)
+        self.component_registry = COMPONENT_REGISTRY.create(self.zk_client)
         self.system_config_cache = SystemConfigCache(self.zk_client,
                                                      self.wake_event.set)
         self.unparsed_config_cache = UnparsedConfigCache(self.zk_client)
@@ -2538,5 +2538,4 @@ class Scheduler(threading.Thread):
             tenant.semaphore_handler.release(item, job)
 
     def createZKContext(self, lock, log):
-        return ZKContext(self.zk_client, lock, self.stop_event, log,
-                         self.component_registry)
+        return ZKContext(self.zk_client, lock, self.stop_event, log)
diff --git a/zuul/web/__init__.py b/zuul/web/__init__.py
index bb69480e7f..0b7facd9f6 100755
--- a/zuul/web/__init__.py
+++ b/zuul/web/__init__.py
@@ -59,7 +59,7 @@ from zuul.model import (
 )
 from zuul.version import get_version_string
 from zuul.zk import ZooKeeperClient
-from zuul.zk.components import ComponentRegistry, WebComponent
+from zuul.zk.components import COMPONENT_REGISTRY, WebComponent
 from zuul.zk.config_cache import SystemConfigCache
 from zuul.zk.event_queues import (
     TenantManagementEventQueue,
@@ -269,7 +269,7 @@ class LogStreamHandler(WebSocket):
 
         try:
             port_location = streamer_utils.getJobLogStreamAddress(
-                self.zuulweb.executor_api, self.zuulweb.component_registry,
+                self.zuulweb.executor_api,
                 request['uuid'], source_zone=self.zuulweb.zone)
         except exceptions.StreamingError as e:
             return self.logClose(4011, str(e))
@@ -1723,7 +1723,7 @@ class ZuulWeb(object):
                                                   self.component_info)
         self.monitoring_server.start()
 
-        self.component_registry = ComponentRegistry(self.zk_client)
+        self.component_registry = COMPONENT_REGISTRY.create(self.zk_client)
 
         self.system_config_cache_wake_event = threading.Event()
         self.system_config_cache = SystemConfigCache(
@@ -1763,8 +1763,7 @@ class ZuulWeb(object):
             self.zk_client
         )
 
-        self.zk_context = ZKContext(self.zk_client, None, None, self.log,
-                                    self.component_registry)
+        self.zk_context = ZKContext(self.zk_client, None, None, self.log)
 
         command_socket = get_default(
             self.config, 'web', 'command_socket',
diff --git a/zuul/zk/branch_cache.py b/zuul/zk/branch_cache.py
index 950d470a8e..56930093b8 100644
--- a/zuul/zk/branch_cache.py
+++ b/zuul/zk/branch_cache.py
@@ -94,8 +94,7 @@ class BranchCache:
 
         # TODO: standardize on a stop event for connections and add it
         # to the context.
-        self.zk_context = ZKContext(zk_client, self.wlock, None, self.log,
-                                    component_registry)
+        self.zk_context = ZKContext(zk_client, self.wlock, None, self.log)
 
         with locked(self.wlock):
             try:
diff --git a/zuul/zk/components.py b/zuul/zk/components.py
index 94bf416c3e..6554297e15 100644
--- a/zuul/zk/components.py
+++ b/zuul/zk/components.py
@@ -27,6 +27,26 @@ from zuul import model
 COMPONENTS_ROOT = "/zuul/components"
 
 
+class GlobalRegistry:
+    def __init__(self):
+        self.registry = None
+
+    def create(self, zk_client):
+        if not self.registry:
+            self.registry = ComponentRegistry(zk_client)
+        return self.registry
+
+    def clearRegistry(self):
+        self.registry = None
+
+    @property
+    def model_api(self):
+        return self.registry.model_api
+
+
+COMPONENT_REGISTRY = GlobalRegistry()
+
+
 class BaseComponent(ZooKeeperBase):
     """
     Read/write component object.
diff --git a/zuul/zk/semaphore.py b/zuul/zk/semaphore.py
index 9e72cf8963..04a4f256ea 100644
--- a/zuul/zk/semaphore.py
+++ b/zuul/zk/semaphore.py
@@ -21,6 +21,7 @@ from kazoo.exceptions import BadVersionError, NoNodeError
 
 from zuul.lib.logutil import get_annotated_logger
 from zuul.zk import ZooKeeperSimpleBase
+from zuul.zk.components import COMPONENT_REGISTRY
 
 
 def holdersFromData(data):
@@ -38,12 +39,10 @@ class SemaphoreHandler(ZooKeeperSimpleBase):
 
     semaphore_root = "/zuul/semaphores"
 
-    def __init__(self, client, statsd, tenant_name, layout,
-                 component_registry):
+    def __init__(self, client, statsd, tenant_name, layout):
         super().__init__(client)
         self.layout = layout
         self.statsd = statsd
-        self.component_registry = component_registry
         self.tenant_name = tenant_name
         self.tenant_root = f"{self.semaphore_root}/{tenant_name}"
 
@@ -110,7 +109,7 @@ class SemaphoreHandler(ZooKeeperSimpleBase):
         # semaphore is there, check max
         while len(semaphore_holders) < self._max_count(semaphore.name):
             # MODEL_API: >1
-            if self.component_registry.model_api > 1:
+            if COMPONENT_REGISTRY.model_api > 1:
                 semaphore_holders.append(semaphore_handle)
             else:
                 semaphore_holders.append(legacy_handle)
@@ -212,10 +211,10 @@ class SemaphoreHandler(ZooKeeperSimpleBase):
 
     def cleanupLeaks(self):
         # MODEL_API: >1
-        if self.component_registry.model_api < 2:
+        if COMPONENT_REGISTRY.model_api < 2:
             self.log.warning("Skipping semaphore cleanup since minimum model "
                              "API is %s (needs >= 2)",
-                             self.component_registry.model_api)
+                             COMPONENT_REGISTRY.model_api)
             return
 
         for semaphore_name in self.getSemaphores():
diff --git a/zuul/zk/zkobject.py b/zuul/zk/zkobject.py
index 92b0cfcee5..45eb2b8e22 100644
--- a/zuul/zk/zkobject.py
+++ b/zuul/zk/zkobject.py
@@ -23,25 +23,19 @@ from kazoo.exceptions import (
 
 from zuul.zk import sharding
 from zuul.zk.exceptions import InvalidObjectError
-from zuul import model
 
 
 class ZKContext:
-    def __init__(self, zk_client, lock, stop_event, log, registry):
+    def __init__(self, zk_client, lock, stop_event, log):
         self.client = zk_client.client
         self.lock = lock
         self.stop_event = stop_event
         self.log = log
-        self.registry = registry
 
     def sessionIsValid(self):
         return ((not self.lock or self.lock.is_still_valid()) and
                 (not self.stop_event or not self.stop_event.is_set()))
 
-    @property
-    def model_api(self):
-        return self.registry.model_api
-
 
 class LocalZKContext:
     """A Local ZKContext that means don't actually write anything to ZK"""
@@ -51,15 +45,10 @@ class LocalZKContext:
         self.lock = None
         self.stop_event = None
         self.log = log
-        self.registry = None
 
     def sessionIsValid(self):
         return True
 
-    @property
-    def model_api(self):
-        return model.MODEL_API
-
 
 class ZKObject:
     _retry_interval = 5