diff --git a/docs/resources/service.md b/docs/resources/service.md
index 036e291c5..b681047c6 100644
--- a/docs/resources/service.md
+++ b/docs/resources/service.md
@@ -370,7 +370,7 @@ Optional:
 
 - **config_name** (String) Name of the config that this references, but this is just provided for lookup/display purposes. The config in the reference will be identified by its ID
 - **file_gid** (String) Represents the file GID. Defaults to `0`.
-- **file_mode** (Number) Represents represents the FileMode of the file. Defaults to `0o444`.
+- **file_mode** (String) Represents represents the FileMode of the file. Defaults to `0o444`.
 - **file_uid** (String) Represents the file UID. Defaults to `0`.
 
 
@@ -515,7 +515,7 @@ Required:
 Optional:
 
 - **file_gid** (String) Represents the file GID. Defaults to `0`
-- **file_mode** (Number) Represents represents the FileMode of the file. Defaults to `0o444`
+- **file_mode** (String) Represents represents the FileMode of the file. Defaults to `0o444`
 - **file_uid** (String) Represents the file UID. Defaults to `0`
 - **secret_name** (String) Name of the secret that this references, but this is just provided for lookup/display purposes. The config in the reference will be identified by its ID
 
diff --git a/internal/provider/file_mode.go b/internal/provider/file_mode.go
new file mode 100644
index 000000000..93e60a8a4
--- /dev/null
+++ b/internal/provider/file_mode.go
@@ -0,0 +1,56 @@
+package provider
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/hashicorp/go-cty/cty"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+)
+
+const defaultFileMode = "0444"
+
+func convertStrToFileMode(s string) (os.FileMode, error) {
+	if s == "" {
+		s = defaultFileMode
+	}
+	a, err := strconv.ParseInt(s, 8, 32)
+	if err != nil {
+		return 0, err
+	}
+	if a < 0 {
+		return 0, fmt.Errorf("file_mode must be greater equal than 0: %d", a)
+	}
+	if a > 0o4777 {
+		return 0, fmt.Errorf("file_mode must be less equal than 0o4777: %d", a)
+	}
+	return os.FileMode(a), nil
+}
+
+func fileModeDiffSuppressFunc(k, oldV, newV string, d *schema.ResourceData) bool {
+	log.Printf("[DEBUG] DiffSuppressFunc(key: %s, old value: %s, new value: %s)", k, oldV, newV)
+	if oldV == newV {
+		return true
+	}
+	a, err := convertStrToFileMode(oldV)
+	if err != nil {
+		log.Printf("[DEBUG] DiffSuppressFunc(key: %s, old value: %s, new value: %s): old value is invalid: %s", k, oldV, newV, err.Error())
+		return false
+	}
+	b, err := convertStrToFileMode(newV)
+	if err != nil {
+		log.Printf("[DEBUG] DiffSuppressFunc(key: %s, old value: %s, new value: %s): new value is invalid: %s", k, oldV, newV, err.Error())
+		return false
+	}
+	return a == b
+}
+
+func fileModeSchemaValidateDiagFunc(value interface{}, ctyPath cty.Path) diag.Diagnostics {
+	if _, err := convertStrToFileMode(value.(string)); err != nil {
+		return diag.FromErr(err)
+	}
+	return nil
+}
diff --git a/internal/provider/helper.go b/internal/provider/helper.go
new file mode 100644
index 000000000..2b6f3cb94
--- /dev/null
+++ b/internal/provider/helper.go
@@ -0,0 +1,21 @@
+package provider
+
+import "hash/crc32"
+
+// hashString hashes a string to a unique hashcode.
+//
+// crc32 returns a uint32, but for our use we need
+// and non negative integer. Here we cast to an integer
+// and invert it if the result is negative.
+// https://www.terraform.io/docs/extend/guides/v2-upgrade-guide.html#removal-of-helper-hashcode-package
+func hashString(s string) int {
+	v := int(crc32.ChecksumIEEE([]byte(s)))
+	if v >= 0 {
+		return v
+	}
+	if -v >= 0 {
+		return -v
+	}
+	// v == MinInt
+	return 0
+}
diff --git a/internal/provider/resource_docker_service.go b/internal/provider/resource_docker_service.go
index d96c158c6..dab33a8ff 100644
--- a/internal/provider/resource_docker_service.go
+++ b/internal/provider/resource_docker_service.go
@@ -439,11 +439,12 @@ func resourceDockerService() *schema.Resource {
 													Optional:    true,
 												},
 												"file_mode": {
-													Type:             schema.TypeInt,
+													Type:             schema.TypeString,
 													Description:      "Represents represents the FileMode of the file. Defaults to `0o444`",
-													Default:          0o444,
+													Default:          defaultFileMode,
 													Optional:         true,
-													ValidateDiagFunc: validateIntegerGeqThan(0),
+													ValidateDiagFunc: fileModeSchemaValidateDiagFunc,
+													DiffSuppressFunc: fileModeDiffSuppressFunc,
 												},
 											},
 										},
@@ -452,6 +453,9 @@ func resourceDockerService() *schema.Resource {
 										Type:        schema.TypeSet,
 										Description: "References to zero or more configs that will be exposed to the service",
 										Optional:    true,
+										Set: func(v interface{}) int {
+											return hashString(v.(map[string]interface{})["config_id"].(string))
+										},
 										Elem: &schema.Resource{
 											Schema: map[string]*schema.Schema{
 												"config_id": {
@@ -482,11 +486,12 @@ func resourceDockerService() *schema.Resource {
 													Optional:    true,
 												},
 												"file_mode": {
-													Type:             schema.TypeInt,
+													Type:             schema.TypeString,
 													Description:      "Represents represents the FileMode of the file. Defaults to `0o444`.",
-													Default:          0o444,
+													Default:          defaultFileMode,
 													Optional:         true,
-													ValidateDiagFunc: validateIntegerGeqThan(0),
+													ValidateDiagFunc: fileModeSchemaValidateDiagFunc,
+													DiffSuppressFunc: fileModeDiffSuppressFunc,
 												},
 											},
 										},