Only create swap file space when necessary (#416)

* Only create swap file space when necessary

integration_test/gce/gce_testing.go

@@ -977,20 +977,6 @@ func attemptCreateInstance(ctx context.Context, logger *log.Logger, options VMOp
 			return nil, fmt.Errorf("attemptCreateInstance() failed to configure retries in zypp.conf: %v", err)
 		}
 	}
-
-	if !IsWindows(vm.Platform) {
-		// Enable swap file: https://linuxize.com/post/create-a-linux-swap-file/
-		_, err := RunRemotely(ctx, logger, vm, "", strings.Join([]string{
-			"sudo dd if=/dev/zero of=/swapfile bs=1024 count=102400",
-			"sudo chmod 600 /swapfile",
-			"sudo mkswap /swapfile",
-			"sudo swapon /swapfile",
-		}, " && "))
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	return vm, nil
 }
 

integration_test/ops_agent_test.go

@@ -812,6 +812,20 @@ func metricsForPlatform(platform string) []string {
 }
 
 func testDefaultMetrics(ctx context.Context, t *testing.T, logger *logging.DirectoryLogger, vm *gce.VM, window time.Duration) {
+	if !gce.IsWindows(vm.Platform) {
+		// Enable swap file: https://linuxize.com/post/create-a-linux-swap-file/
+		// We do this so that swap file metrics will show up.
+		_, err := gce.RunRemotely(ctx, logger.ToMainLog(), vm, "", strings.Join([]string{
+			"sudo dd if=/dev/zero of=/swapfile bs=1024 count=102400",
+			"sudo chmod 600 /swapfile",
+			"sudo mkswap /swapfile",
+			"sudo swapon /swapfile",
+		}, " && "))
+		if err != nil {
+			t.Fatalf("Failed to enable swap file: %v", err)
+		}
+	}
+
 	// First make sure that the uptime metrics are being uploaded.
 	var uptimeWaitGroup sync.WaitGroup
 	regexes := agentVersionRegexesForPlatform(vm.Platform)