diff --git a/daemon/config/config.go b/daemon/config/config.go
index 0d3021647..79d7f11f8 100644
--- a/daemon/config/config.go
+++ b/daemon/config/config.go
@@ -17,6 +17,7 @@ import (
 	"github.com/alibaba/pouch/pkg/utils"
 	"github.com/alibaba/pouch/storage/volume"
 
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/pflag"
 )
 
@@ -131,6 +132,10 @@ func (cfg *Config) GetCgroupDriver() string {
 
 // Validate validates the user input config.
 func (cfg *Config) Validate() error {
+	// for debug config file.
+	b, _ := json.Marshal(cfg)
+	logrus.Debugf("daemon config: (%s)", string(b))
+
 	// deduplicated elements in slice if there is any.
 	cfg.Listen = utils.DeDuplicate(cfg.Listen)
 	cfg.Labels = utils.DeDuplicate(cfg.Labels)
@@ -191,9 +196,7 @@ func (cfg *Config) MergeConfigurations(flagSet *pflag.FlagSet) error {
 	}
 
 	// merge configurations from command line flags and config file
-	err = mergeConfigurations(fileConfig, cfg.delValue(flagSet, fileFlags))
-	return err
-
+	return mergeConfigurations(fileConfig, cfg.delValue(flagSet, fileFlags))
 }
 
 // delValue deleles value in config, since we do not do conflict check for slice
diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
index 705dd7d6f..7b9a1b9b2 100644
--- a/pkg/utils/utils.go
+++ b/pkg/utils/utils.go
@@ -122,6 +122,8 @@ func isEmptyValue(v reflect.Value) bool {
 	switch v.Kind() {
 	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
 		return v.Len() == 0
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
 	case reflect.Uintptr:
 		return v.Uint() == 0
 	case reflect.Float32, reflect.Float64:
diff --git a/pkg/utils/utils_test.go b/pkg/utils/utils_test.go
index b9f1a7ce8..6cb7c7a52 100644
--- a/pkg/utils/utils_test.go
+++ b/pkg/utils/utils_test.go
@@ -91,7 +91,7 @@ func TestMerge(t *testing.T) {
 		}, {
 			src:      &simple{},
 			dest:     &simple{Sa: 1, Sb: "hello", Sc: true, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 22}},
-			expected: &simple{Sa: 0, Sb: "hello", Sc: false, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 0}},
+			expected: &simple{Sa: 1, Sb: "hello", Sc: false, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 22}},
 			ok:       true,
 		}, {
 			src:      &simple{Sa: 1, Sc: true, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 11}, Sf: []string{"foo"}},
@@ -101,7 +101,7 @@ func TestMerge(t *testing.T) {
 		}, {
 			src:      &simple{Sa: 0, Sc: false, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 11}, Sf: []string{"foo"}},
 			dest:     &simple{Sa: 2, Sb: "world", Sc: true, Sd: map[string]string{"go": "old"}, Se: nestS{Na: 22}, Sf: []string{"foo"}},
-			expected: &simple{Sa: 0, Sb: "world", Sc: false, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 11}, Sf: []string{"foo", "foo"}},
+			expected: &simple{Sa: 2, Sb: "world", Sc: false, Sd: map[string]string{"go": "gogo"}, Se: nestS{Na: 11}, Sf: []string{"foo", "foo"}},
 			ok:       true,
 		}, {
 			src:      &simple{Sd: map[string]string{"go": "gogo", "a": "b"}},