diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 699c2025635e32e3e62c02410a9e0d0144ef2b10..0fbdb06944cdcdbe3fdaf4f7d8dfe85565630a1d 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -11427,8 +11427,8 @@ class TLReplaceDisks(Tasklet):
 
     feedback_fn("Replacing disk(s) %s for instance '%s'" %
                 (utils.CommaJoin(self.disks), self.instance.name))
-    feedback_fn("Current primary node: %s", self.instance.primary_node)
-    feedback_fn("Current seconary node: %s",
+    feedback_fn("Current primary node: %s" % self.instance.primary_node)
+    feedback_fn("Current seconary node: %s" %
                 utils.CommaJoin(self.instance.secondary_nodes))
 
     activate_disks = (self.instance.admin_state != constants.ADMINST_UP)