diff --git a/cmd/sharded-test-server/cache.go b/cmd/sharded-test-server/cache.go
index 6bcfa9764e6..fb79e0a8d00 100644
--- a/cmd/sharded-test-server/cache.go
+++ b/cmd/sharded-test-server/cache.go
@@ -73,6 +73,13 @@ func startCacheServer(ctx context.Context, logDirPath, workingDir string, synthe
 		return nil, "", err
 	}
 
+	defer func() {
+		err = logFile.Close()
+		if err != nil {
+			klog.ErrorS(err, "failed to close the log file")
+		}
+	}()
+
 	writer := helpers.NewHeadWriter(logFile, out)
 	cmd.Stdout = writer
 	cmd.Stdin = os.Stdin
diff --git a/cmd/sharded-test-server/frontproxy.go b/cmd/sharded-test-server/frontproxy.go
index 95187a90c8c..9029776c507 100644
--- a/cmd/sharded-test-server/frontproxy.go
+++ b/cmd/sharded-test-server/frontproxy.go
@@ -157,6 +157,13 @@ func startFrontProxy(
 		return err
 	}
 
+	defer func() {
+		err = logFile.Close()
+		if err != nil {
+			klog.ErrorS(err, "failed to close the log file")
+		}
+	}()
+
 	writer := helpers.NewHeadWriter(logFile, out)
 	cmd.Stdout = writer
 	cmd.Stdin = os.Stdin
diff --git a/cmd/sharded-test-server/virtual.go b/cmd/sharded-test-server/virtual.go
index bb97453128e..ad442fab0f2 100644
--- a/cmd/sharded-test-server/virtual.go
+++ b/cmd/sharded-test-server/virtual.go
@@ -209,6 +209,13 @@ func (v *VirtualWorkspace) start(ctx context.Context) error {
 		return err
 	}
 
+	defer func() {
+		err = logFile.Close()
+		if err != nil {
+			klog.ErrorS(err, "failed to close the log file")
+		}
+	}()
+
 	v.writer = helpers.NewHeadWriter(logFile, out)
 	cmd.Stdout = v.writer
 	cmd.Stdin = os.Stdin
diff --git a/cmd/test-server/kcp/shard.go b/cmd/test-server/kcp/shard.go
index 9ec42dfbdb8..d15e753661a 100644
--- a/cmd/test-server/kcp/shard.go
+++ b/cmd/test-server/kcp/shard.go
@@ -117,6 +117,13 @@ func (s *Shard) Start(ctx context.Context, quiet bool) error {
 		return err
 	}
 
+	defer func() {
+		err = logFile.Close()
+		if err != nil {
+			klog.ErrorS(err, "failed to close the log file")
+		}
+	}()
+
 	s.writer = helpers.NewHeadWriter(logFile, out)
 	cmd.Stdout = s.writer
 	cmd.Stdin = os.Stdin