diff --git a/buildman/manager/ephemeral.py b/buildman/manager/ephemeral.py
index 7ea9ea8eb..73d5450d9 100644
--- a/buildman/manager/ephemeral.py
+++ b/buildman/manager/ephemeral.py
@@ -89,6 +89,16 @@ class EphemeralBuilderManager(BaseManager):
         except (ProtocolError, etcd.EtcdException):
           logger.exception('Exception on etcd watch: %s', etcd_key)
 
+        except etcd.EtcdEventIndexCleared:
+          # This happens if etcd2 has moved forward too fast for us to start watching
+          # at the index we retrieved. We therefore start a new watch at HEAD and
+          # call the method to read the key and load ALL realms to handle any we might
+          # have missed.
+          # TODO: Remove this hack once Etcd is fixed.
+          logger.exception('Etcd moved forward too quickly. Restarting watch cycle.')
+          new_index = None
+          async(self._register_existing_realms())
+
       if watch_task_key not in self._watch_tasks or self._watch_tasks[watch_task_key].done():
         self._watch_etcd(etcd_key, change_callback, start_index=new_index)
 
@@ -165,18 +175,35 @@ class EphemeralBuilderManager(BaseManager):
     logger.debug('Registering realm with manager: %s', realm_spec['realm'])
     component = self.register_component(realm_spec['realm'], BuildComponent,
                                         token=realm_spec['token'])
+
+    if component in self._component_to_job:
+      logger.debug('Realm already registered with manager: %s', realm_spec['realm'])
+      return component
+
     build_job = BuildJob(AttrDict(realm_spec['job_queue_item']))
     self._component_to_job[component] = build_job
     self._component_to_builder[component] = realm_spec['builder_id']
     self._job_uuid_to_component[build_job.job_details['build_uuid']] = component
+    return component
 
   @coroutine
   def _register_existing_realms(self):
     try:
       all_realms = yield From(self._etcd_client.read(self._etcd_realm_prefix, recursive=True))
+
+      # Register all existing realms found.
+      encountered = set()
       for realm in all_realms.children:
         if not realm.dir:
-          self._register_realm(json.loads(realm.value))
+          component = self._register_realm(json.loads(realm.value))
+          encountered.add(component)
+
+      # Remove any components not encountered so we can clean up.
+      for found in list(self._component_to_job.keys()):
+        if not found in encountered:
+          self._component_to_job.pop(component)
+          self._component_to_builder.pop(component)
+
     except (KeyError, etcd.EtcdKeyError):
       # no realms have been registered yet
       pass
diff --git a/buildman/server.py b/buildman/server.py
index 878b8d5fd..655b78495 100644
--- a/buildman/server.py
+++ b/buildman/server.py
@@ -36,6 +36,7 @@ class BuilderServer(object):
     self._loop = None
     self._current_status = BuildServerStatus.STARTING
     self._current_components = []
+    self._realm_map = {}
     self._job_count = 0
 
     self._session_factory = RouterSessionFactory(RouterFactory())
@@ -111,6 +112,9 @@ class BuilderServer(object):
         BaseComponent.
     """
     logger.debug('Registering component with realm %s', realm)
+    if realm in self._realm_map:
+      logger.debug('Component with realm %s already registered', realm)
+      return self._realm_map[realm]
 
     component = component_klass(types.ComponentConfig(realm=realm), realm=realm, **kwargs)
     component.server = self
@@ -119,6 +123,7 @@ class BuilderServer(object):
     component.user_files = self._user_files
     component.registry_hostname = self._registry_hostname
 
+    self._realm_map[realm] = component
     self._current_components.append(component)
     self._session_factory.add(component)
     return component
@@ -127,6 +132,7 @@ class BuilderServer(object):
     logger.debug('Unregistering component with realm %s and token %s',
                   component.builder_realm, component.expected_token)
 
+    self._realm_map.pop(component.builder_realm)
     self._current_components.remove(component)
     self._session_factory.remove(component)