diff --git a/load.go b/load.go
index fe6ca10..4b0fcf3 100644
--- a/load.go
+++ b/load.go
@@ -84,7 +84,7 @@ func LoadArgsMain() (unit Unit, ok bool, err error) {
 	unit = Unit{
 		Name:  "arg-main",
 		Group: DefaultGroup,
-		Kind:  "daemon",
+		Kind:  KindDaemon,
 		ExecuteOptions: ExecuteOptions{
 			Command: args,
 		},
@@ -106,9 +106,9 @@ func LoadEnvMain() (unit Unit, ok bool, err error) {
 	if group == "" {
 		group = DefaultGroup
 	}
-	kind := "daemon"
+	kind := KindDaemon
 	if once, _ := strconv.ParseBool(strings.TrimSpace(os.Getenv("MINIT_MAIN_ONCE"))); once {
-		kind = "once"
+		kind = KindOnce
 		return
 	}
 	var command []string
diff --git a/runner.go b/runner.go
index 6345c67..2947f59 100644
--- a/runner.go
+++ b/runner.go
@@ -20,31 +20,31 @@ type RunnerFactory struct {
 
 var (
 	RunnerFactories = map[string]*RunnerFactory{
-		"render": {
+		KindRender: {
 			Level: RunnerL1,
 			Create: func(unit Unit, logger *mlog.Logger) (Runner, error) {
 				return NewRenderRunner(unit, logger)
 			},
 		},
-		"once": {
+		KindOnce: {
 			Level: RunnerL2,
 			Create: func(unit Unit, logger *mlog.Logger) (Runner, error) {
 				return NewOnceRunner(unit, logger)
 			},
 		},
-		"daemon": {
+		KindDaemon: {
 			Level: RunnerL3,
 			Create: func(unit Unit, logger *mlog.Logger) (Runner, error) {
 				return NewDaemonRunner(unit, logger)
 			},
 		},
-		"cron": {
+		KindCron: {
 			Level: RunnerL3,
 			Create: func(unit Unit, logger *mlog.Logger) (Runner, error) {
 				return NewCronRunner(unit, logger)
 			},
 		},
-		"logrotate": {
+		KindLogrotate: {
 			Level: RunnerL3,
 			Create: func(unit Unit, logger *mlog.Logger) (Runner, error) {
 				return NewLogrotateRunner(unit, logger)
diff --git a/runner_cron.go b/runner_cron.go
index 65c2631..e9889c6 100644
--- a/runner_cron.go
+++ b/runner_cron.go
@@ -7,6 +7,8 @@ import (
 	"github.com/robfig/cron/v3"
 )
 
+const KindCron = "cron"
+
 type CronRunner struct {
 	Unit
 	logger *mlog.Logger
diff --git a/runner_daemon.go b/runner_daemon.go
index 66a76d6..f46ff30 100644
--- a/runner_daemon.go
+++ b/runner_daemon.go
@@ -7,6 +7,8 @@ import (
 	"time"
 )
 
+const KindDaemon = "daemon"
+
 type DaemonRunner struct {
 	Unit
 	logger *mlog.Logger
diff --git a/runner_logrotate.go b/runner_logrotate.go
index 9a2c4e3..74bc245 100644
--- a/runner_logrotate.go
+++ b/runner_logrotate.go
@@ -14,6 +14,8 @@ import (
 	"time"
 )
 
+const KindLogrotate = "logrotate"
+
 // filename mark
 // daily: FILENAME.ROT2020-06-02.EXT
 // filesize: FILENAME.ROT000000000001.EXT (%012d)
diff --git a/runner_once.go b/runner_once.go
index b9587ef..0694ebd 100644
--- a/runner_once.go
+++ b/runner_once.go
@@ -6,6 +6,8 @@ import (
 	"github.com/acicn/minit/pkg/mlog"
 )
 
+const KindOnce = "once"
+
 type OnceRunner struct {
 	Unit
 	logger *mlog.Logger
diff --git a/runner_render.go b/runner_render.go
index d5eef3d..48ce837 100644
--- a/runner_render.go
+++ b/runner_render.go
@@ -13,6 +13,8 @@ import (
 	"text/template"
 )
 
+const KindRender = "render"
+
 type RenderRunner struct {
 	Unit
 	logger *mlog.Logger