--- mdadm-4.1/mdadm.c~	2018-12-12 17:15:41.359619760 +0800
+++ mdadm-4.1/mdadm.c	2018-12-12 17:16:09.265626436 +0800
@@ -1553,6 +1553,10 @@
 			c.delay = DEFAULT_BITMAP_DELAY;
 
 		if (c.nodes) {
+			pr_err("WARNING: bitmap=clustered is Technology Preview.\n");
+			pr_err("For more information on Technology Preview features, visit:\n");
+			pr_err("https://access.redhat.com/support/offerings/techpreview/ \n");
+
 			if (!s.bitmap_file ||
 			    strcmp(s.bitmap_file, "clustered") != 0) {
 				pr_err("--nodes argument only compatible with --bitmap=clustered\n");