1 files changed, 7 insertions, 0 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 8e54ef84b2..4a75eb6b21 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -32,6 +32,7 @@ from synapse.appservice import ApplicationService
 from synapse.http import get_request_user_agent
 from synapse.http.site import SynapseRequest
 from synapse.logging.opentracing import (
+    SynapseTags,
     active_span,
     force_tracing,
     start_active_span,
@@ -161,6 +162,12 @@ class Auth:
                 parent_span.set_tag(
                     "authenticated_entity", requester.authenticated_entity
                 )
+                # We tag the Synapse instance name so that it's an easy jumping
+                # off point into the logs. Can also be used to filter for an
+                # instance that is under load.
+                parent_span.set_tag(
+                    SynapseTags.INSTANCE_NAME, self.hs.get_instance_name()
+                )
                 parent_span.set_tag("user_id", requester.user.to_string())
                 if requester.device_id is not None:
                     parent_span.set_tag("device_id", requester.device_id)