diff --git a/src/frostfs_testlib/s3/interfaces.py b/src/frostfs_testlib/s3/interfaces.py
index da4fc6b..c084484 100644
--- a/src/frostfs_testlib/s3/interfaces.py
+++ b/src/frostfs_testlib/s3/interfaces.py
@@ -58,6 +58,10 @@ class S3ClientWrapper(HumanReadableABC):
     def set_endpoint(self, s3gate_endpoint: str):
         """Set endpoint"""
 
+    @abstractmethod
+    def set_iam_endpoint(self, iam_endpoint: str):
+        """Set iam endpoint"""
+
     @abstractmethod
     def create_bucket(
         self,
diff --git a/src/frostfs_testlib/steps/metrics.py b/src/frostfs_testlib/steps/metrics.py
index 29e49d4..a9e545a 100644
--- a/src/frostfs_testlib/steps/metrics.py
+++ b/src/frostfs_testlib/steps/metrics.py
@@ -1,8 +1,8 @@
 import re
 
 from frostfs_testlib import reporter
-from frostfs_testlib.testing.test_control import wait_for_success
 from frostfs_testlib.storage.cluster import ClusterNode
+from frostfs_testlib.testing.test_control import wait_for_success
 
 
 @reporter.step("Check metrics result")
@@ -19,7 +19,7 @@ def check_metrics_counter(
         counter_act += get_metrics_value(cluster_node, parse_from_command, **metrics_greps)
     assert eval(
         f"{counter_act} {operator} {counter_exp}"
-    ), f"Expected: {counter_exp} {operator} Actual: {counter_act} in node: {cluster_node}"
+    ), f"Expected: {counter_exp} {operator} Actual: {counter_act} in nodes: {cluster_nodes}"
 
 
 @reporter.step("Get metrics value from node: {node}")