Index: head/stand/defaults/loader.conf
===================================================================
--- head/stand/defaults/loader.conf
+++ head/stand/defaults/loader.conf
@@ -33,6 +33,11 @@
 screensave_load="NO"		# Set to YES to load a screensaver module
 screensave_name="green_saver"	# Set to the name of the screensaver module
 
+###  Early hostid configuration ############################
+hostuuid_load="YES"
+hostuuid_name="/etc/hostid"
+hostuuid_type="hostuuid"
+
 ###  Random number generator configuration  ##################
 # See rc.conf(5). The entropy_boot_file config variable must agree with the
 # settings below.
Index: head/sys/kern/kern_jail.c
===================================================================
--- head/sys/kern/kern_jail.c
+++ head/sys/kern/kern_jail.c
@@ -48,6 +48,7 @@
 #include <sys/taskqueue.h>
 #include <sys/fcntl.h>
 #include <sys/jail.h>
+#include <sys/linker.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/racct.h>
@@ -61,6 +62,7 @@
 #include <sys/socket.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
+#include <sys/uuid.h>
 #include <sys/vnode.h>
 
 #include <net/if.h>
@@ -75,6 +77,7 @@
 #include <security/mac/mac_framework.h>
 
 #define	DEFAULT_HOSTUUID	"00000000-0000-0000-0000-000000000000"
+#define	PRISON0_HOSTUUID_MODULE	"hostuuid"
 
 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
 static MALLOC_DEFINE(M_PRISON_RACCT, "prison_racct", "Prison racct structures");
@@ -218,10 +221,38 @@
 void
 prison0_init(void)
 {
+	uint8_t *file, *data;
+	size_t size;
 
 	prison0.pr_cpuset = cpuset_ref(thread0.td_cpuset);
 	prison0.pr_osreldate = osreldate;
 	strlcpy(prison0.pr_osrelease, osrelease, sizeof(prison0.pr_osrelease));
+
+	/* If we have a preloaded hostuuid, use it. */
+	file = preload_search_by_type(PRISON0_HOSTUUID_MODULE);
+	if (file != NULL) {
+		data = preload_fetch_addr(file);
+		size = preload_fetch_size(file);
+		if (data != NULL) {
+			/*
+			 * The preloaded data may include trailing whitespace, almost
+			 * certainly a newline; skip over any whitespace or
+			 * non-printable characters to be safe.
+			 */
+			while (size > 0 && data[size - 1] <= 0x20) {
+				data[size--] = '\0';
+			}
+			if (validate_uuid(data, size, NULL, 0) == 0) {
+				(void)strlcpy(prison0.pr_hostuuid, data,
+				    size + 1);
+			} else if (bootverbose) {
+				printf("hostuuid: preload data malformed: '%s'",
+				    data);
+			}
+		}
+	}
+	if (bootverbose)
+		printf("hostuuid: using %s\n", prison0.pr_hostuuid);
 }
 
 /*