diff --git a/opentelekomcloud/acceptance/css/resource_opentelekomcloud_css_cluster_v1_test.go b/opentelekomcloud/acceptance/css/resource_opentelekomcloud_css_cluster_v1_test.go
index c0ad31858..824c1d67f 100644
--- a/opentelekomcloud/acceptance/css/resource_opentelekomcloud_css_cluster_v1_test.go
+++ b/opentelekomcloud/acceptance/css/resource_opentelekomcloud_css_cluster_v1_test.go
@@ -82,6 +82,30 @@ func TestAccCssClusterV1_tags(t *testing.T) {
 	})
 }
 
+func TestAccCssClusterV1_Opensearch(t *testing.T) {
+	name := fmt.Sprintf("css-%s", acctest.RandString(10))
+	var cluster clusters.Cluster
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck: func() {
+			common.TestAccPreCheck(t)
+			quotas.BookMany(t, sharedFlavorQuotas(t, 2, 40))
+		},
+		ProviderFactories: common.TestAccProviderFactories,
+		CheckDestroy:      testAccCheckCssClusterV1Destroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccCssClusterV1Opensearch(name),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckCssClusterV1Exists(resourceClusterName, &cluster),
+					resource.TestCheckResourceAttr(resourceClusterName, "nodes.#", "1"),
+					resource.TestCheckResourceAttr(resourceClusterName, "datastore.version", "Opensearch_1.3.6"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccCssClusterV1_validateDiskAndFlavor(t *testing.T) {
 	name := fmt.Sprintf("css-%s", acctest.RandString(10))
 
@@ -481,3 +505,36 @@ resource "opentelekomcloud_css_cluster_v1" "cluster" {
 }
 `, common.DataSourceSecGroupDefault, common.DataSourceSubnet, name, env.OS_KMS_ID, env.OS_AVAILABILITY_ZONE)
 }
+
+func testAccCssClusterV1Opensearch(name string) string {
+	return fmt.Sprintf(`
+%s
+
+%s
+
+resource "opentelekomcloud_css_cluster_v1" "cluster" {
+  expect_node_num = 1
+  name            = "%s"
+  node_config {
+    flavor = "css.medium.8"
+    network_info {
+      security_group_id = data.opentelekomcloud_networking_secgroup_v2.default_secgroup.id
+      network_id        = data.opentelekomcloud_vpc_subnet_v1.shared_subnet.network_id
+      vpc_id            = data.opentelekomcloud_vpc_subnet_v1.shared_subnet.vpc_id
+    }
+    volume {
+      volume_type = "COMMON"
+      size        = 40
+    }
+
+    availability_zone = "%s"
+  }
+  datastore {
+    version = "Opensearch_1.3.6"
+  }
+  enable_https     = true
+  enable_authority = true
+  admin_pass       = "QwertyUI!"
+}
+`, common.DataSourceSecGroupDefault, common.DataSourceSubnet, name, env.OS_AVAILABILITY_ZONE)
+}
diff --git a/opentelekomcloud/services/css/resource_opentelekomcloud_css_cluster_v1.go b/opentelekomcloud/services/css/resource_opentelekomcloud_css_cluster_v1.go
index 372c9a474..5702c3ebd 100644
--- a/opentelekomcloud/services/css/resource_opentelekomcloud_css_cluster_v1.go
+++ b/opentelekomcloud/services/css/resource_opentelekomcloud_css_cluster_v1.go
@@ -11,7 +11,6 @@ import (
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
-	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 	golangsdk "github.com/opentelekomcloud/gophertelekomcloud"
 	"github.com/opentelekomcloud/gophertelekomcloud/openstack/css/v1/clusters"
 	"github.com/opentelekomcloud/gophertelekomcloud/openstack/css/v1/flavors"
@@ -161,9 +160,9 @@ func ResourceCssClusterV1() *schema.Resource {
 							Type:     schema.TypeString,
 							Optional: true,
 							ForceNew: true,
-							ValidateFunc: validation.StringInSlice([]string{
-								"7.6.2", "7.9.3", "7.10.2",
-							}, false),
+							// ValidateFunc: validation.StringInSlice([]string{
+							// 	"7.6.2", "7.9.3", "7.10.2", "Opensearch_1.3.6",
+							// }, false),
 							Default: "7.6.2",
 						},
 					},
diff --git a/releasenotes/notes/css-remove-validation-d772b0208fcd2685.yaml b/releasenotes/notes/css-remove-validation-d772b0208fcd2685.yaml
new file mode 100644
index 000000000..9095ed764
--- /dev/null
+++ b/releasenotes/notes/css-remove-validation-d772b0208fcd2685.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    **[CSS]** Remove CSS cluster datastore validation ``resource/opentelekomcloud_css_cluster_v1``
+    (`#2135 <https://github.com/opentelekomcloud/terraform-provider-opentelekomcloud/pull/2135>`_)