diff --git a/sbin/hastd/hast.h b/sbin/hastd/hast.h
index 1f3b3860ed77..71379178e767 100644
--- a/sbin/hastd/hast.h
+++ b/sbin/hastd/hast.h
@@ -127,6 +127,8 @@ struct hast_resource {
 	int	hr_extentsize;
 	/* Maximum number of extents that are kept dirty. */
 	int	hr_keepdirty;
+	/* Path to a program to execute on various events. */
+	char	hr_exec[PATH_MAX];
 
 	/* Path to local component. */
 	char	hr_localpath[PATH_MAX];
diff --git a/sbin/hastd/hastd.c b/sbin/hastd/hastd.c
index 31fc3bf22cc4..c5eebf4a5b4c 100644
--- a/sbin/hastd/hastd.c
+++ b/sbin/hastd/hastd.c
@@ -62,7 +62,7 @@ const char *cfgpath = HAST_CONFIG;
 /* Hastd configuration. */
 static struct hastd_config *cfg;
 /* Was SIGCHLD signal received? */
-static bool sigchld_received = false;
+bool sigchld_received = false;
 /* Was SIGHUP signal received? */
 bool sighup_received = false;
 /* Was SIGINT or SIGTERM signal received? */
@@ -189,6 +189,8 @@ resource_needs_restart(const struct hast_resource *res0,
 			return (true);
 		if (res0->hr_timeout != res1->hr_timeout)
 			return (true);
+		if (strcmp(res0->hr_exec, res1->hr_exec) != 0)
+			return (true);
 	}
 	return (false);
 }
@@ -211,6 +213,8 @@ resource_needs_reload(const struct hast_resource *res0,
 		return (true);
 	if (res0->hr_timeout != res1->hr_timeout)
 		return (true);
+	if (strcmp(res0->hr_exec, res1->hr_exec) != 0)
+		return (true);
 	return (false);
 }
 
diff --git a/sbin/hastd/hastd.h b/sbin/hastd/hastd.h
index 12b384de6ed9..a32e512411ea 100644
--- a/sbin/hastd/hastd.h
+++ b/sbin/hastd/hastd.h
@@ -40,7 +40,7 @@
 #include "hast.h"
 
 extern const char *cfgpath;
-extern bool sigexit_received, sighup_received;
+extern bool sigchld_received, sigexit_received, sighup_received;
 extern struct pidfh *pfh;
 
 void hastd_primary(struct hast_resource *res);
diff --git a/sbin/hastd/parse.y b/sbin/hastd/parse.y
index 5b4f3e5ac087..ca575cf1238b 100644
--- a/sbin/hastd/parse.y
+++ b/sbin/hastd/parse.y
@@ -61,6 +61,7 @@ static char depth0_control[HAST_ADDRSIZE];
 static char depth0_listen[HAST_ADDRSIZE];
 static int depth0_replication;
 static int depth0_timeout;
+static char depth0_exec[PATH_MAX];
 
 static char depth1_provname[PATH_MAX];
 static char depth1_localpath[PATH_MAX];
@@ -130,6 +131,7 @@ yy_config_parse(const char *config, bool exitonerror)
 	depth0_replication = HAST_REPLICATION_MEMSYNC;
 	strlcpy(depth0_control, HAST_CONTROL, sizeof(depth0_control));
 	strlcpy(depth0_listen, HASTD_LISTEN, sizeof(depth0_listen));
+	depth0_exec[0] = '\0';
 
 	lconfig = calloc(1, sizeof(*lconfig));
 	if (lconfig == NULL) {
@@ -190,6 +192,14 @@ yy_config_parse(const char *config, bool exitonerror)
 			 */
 			curres->hr_timeout = depth0_timeout;
 		}
+		if (curres->hr_exec[0] == '\0') {
+			/*
+			 * Exec is not set at resource-level.
+			 * Use global or default setting.
+			 */
+			strlcpy(curres->hr_exec, depth0_exec,
+			    sizeof(curres->hr_exec));
+		}
 	}
 
 	return (lconfig);
@@ -208,7 +218,7 @@ yy_config_free(struct hastd_config *config)
 }
 %}
 
-%token CONTROL LISTEN PORT REPLICATION TIMEOUT EXTENTSIZE RESOURCE NAME LOCAL REMOTE ON
+%token CONTROL LISTEN PORT REPLICATION TIMEOUT EXEC EXTENTSIZE RESOURCE NAME LOCAL REMOTE ON
 %token FULLSYNC MEMSYNC ASYNC
 %token NUM STR OB CB
 
@@ -239,6 +249,8 @@ statement:
 	|
 	timeout_statement
 	|
+	exec_statement
+	|
 	node_statement
 	|
 	resource_statement
@@ -338,6 +350,32 @@ timeout_statement:	TIMEOUT NUM
 	}
 	;
 
+exec_statement:		EXEC STR
+	{
+		switch (depth) {
+		case 0:
+			if (strlcpy(depth0_exec, $2, sizeof(depth0_exec)) >=
+			    sizeof(depth0_exec)) {
+				pjdlog_error("Exec path is too long.");
+				return (1);
+			}
+			break;
+		case 1:
+			if (curres == NULL)
+				break;
+			if (strlcpy(curres->hr_exec, $2,
+			    sizeof(curres->hr_exec)) >=
+			    sizeof(curres->hr_exec)) {
+				pjdlog_error("Exec path is too long.");
+				return (1);
+			}
+			break;
+		default:
+			assert(!"exec at wrong depth level");
+		}
+	}
+	;
+
 node_statement:		ON node_start OB node_entries CB
 	{
 		mynode = false;
@@ -456,6 +494,7 @@ resource_start:	STR
 		curres->hr_previous_role = HAST_ROLE_INIT;
 		curres->hr_replication = -1;
 		curres->hr_timeout = -1;
+		curres->hr_exec[0] = '\0';
 		curres->hr_provname[0] = '\0';
 		curres->hr_localpath[0] = '\0';
 		curres->hr_localfd = -1;
@@ -474,6 +513,8 @@ resource_entry:
 	|
 	timeout_statement
 	|
+	exec_statement
+	|
 	name_statement
 	|
 	local_statement
diff --git a/sbin/hastd/primary.c b/sbin/hastd/primary.c
index dd26f4affb14..bc91266f2c84 100644
--- a/sbin/hastd/primary.c
+++ b/sbin/hastd/primary.c
@@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$");
 #include "hast.h"
 #include "hast_proto.h"
 #include "hastd.h"
+#include "hooks.h"
 #include "metadata.h"
 #include "proto.h"
 #include "pjdlog.h"
@@ -433,6 +434,7 @@ init_environment(struct hast_resource *res __unused)
 	signal(SIGINT, sighandler);
 	signal(SIGTERM, sighandler);
 	signal(SIGHUP, sighandler);
+	signal(SIGCHLD, sighandler);
 }
 
 static void
@@ -791,6 +793,7 @@ hastd_primary(struct hast_resource *res)
 	signal(SIGHUP, SIG_DFL);
 	signal(SIGCHLD, SIG_DFL);
 
+	hook_init();
 	init_local(res);
 	if (real_remote(res) && init_remote(res, NULL, NULL))
 		sync_start();
@@ -1737,6 +1740,9 @@ sighandler(int sig)
 	case SIGHUP:
 		sighup_received = true;
 		break;
+	case SIGCHLD:
+		sigchld_received = true;
+		break;
 	default:
 		assert(!"invalid condition");
 	}
@@ -1788,6 +1794,7 @@ config_reload(void)
 #define MODIFIED_REMOTEADDR	0x1
 #define MODIFIED_REPLICATION	0x2
 #define MODIFIED_TIMEOUT	0x4
+#define MODIFIED_EXEC		0x8
 	modified = 0;
 	if (strcmp(gres->hr_remoteaddr, res->hr_remoteaddr) != 0) {
 		/*
@@ -1805,6 +1812,10 @@ config_reload(void)
 		gres->hr_timeout = res->hr_timeout;
 		modified |= MODIFIED_TIMEOUT;
 	}
+	if (strcmp(gres->hr_exec, res->hr_exec) != 0) {
+		strlcpy(gres->hr_exec, res->hr_exec, sizeof(gres->hr_exec));
+		modified |= MODIFIED_EXEC;
+	}
 	/*
 	 * If only timeout was modified we only need to change it without
 	 * reconnecting.
@@ -1830,7 +1841,8 @@ config_reload(void)
 				    "Unable to set connection timeout");
 			}
 		}
-	} else {
+	} else if ((modified &
+	    (MODIFIED_REMOTEADDR | MODIFIED_REPLICATION)) != 0) {
 		for (ii = 0; ii < ncomps; ii++) {
 			if (!ISREMOTE(ii))
 				continue;
@@ -1844,6 +1856,7 @@ config_reload(void)
 #undef	MODIFIED_REMOTEADDR
 #undef	MODIFIED_REPLICATION
 #undef	MODIFIED_TIMEOUT
+#undef	MODIFIED_EXEC
 
 	pjdlog_info("Configuration reloaded successfully.");
 	return;
@@ -1907,6 +1920,9 @@ guard_thread(void *arg)
 			sighup_received = false;
 			config_reload();
 		}
+		hook_check(sigchld_received);
+		if (sigchld_received)
+			sigchld_received = false;
 
 		timeout = KEEPALIVE_SLEEP;
 		pjdlog_debug(2, "remote_guard: Checking connections.");
diff --git a/sbin/hastd/token.l b/sbin/hastd/token.l
index e5d4ca10df21..05d600c6ef10 100644
--- a/sbin/hastd/token.l
+++ b/sbin/hastd/token.l
@@ -49,6 +49,7 @@ listen			{ DP; return LISTEN; }
 port			{ DP; return PORT; }
 replication		{ DP; return REPLICATION; }
 timeout			{ DP; return TIMEOUT; }
+exec			{ DP; return EXEC; }
 resource		{ DP; return RESOURCE; }
 name			{ DP; return NAME; }
 local			{ DP; return LOCAL; }