diff --git a/aws/resource_aws_appmesh_virtual_node.go b/aws/resource_aws_appmesh_virtual_node.go
index fdabb951904..9cf0e1a5bc5 100644
--- a/aws/resource_aws_appmesh_virtual_node.go
+++ b/aws/resource_aws_appmesh_virtual_node.go
@@ -235,12 +235,13 @@ func resourceAwsAppmeshVirtualNode() *schema.Resource {
 												"namespace_name": {
 													Type:         schema.TypeString,
 													Required:     true,
-													ValidateFunc: validateServiceDiscoveryHttpNamespaceName,
+													ValidateFunc: validation.StringLenBetween(1, 1024),
 												},
 
 												"service_name": {
-													Type:     schema.TypeString,
-													Required: true,
+													Type:         schema.TypeString,
+													Required:     true,
+													ValidateFunc: validation.StringLenBetween(1, 1024),
 												},
 											},
 										},
diff --git a/aws/resource_aws_appmesh_virtual_node_test.go b/aws/resource_aws_appmesh_virtual_node_test.go
index c0fb70fe93a..03795906762 100644
--- a/aws/resource_aws_appmesh_virtual_node_test.go
+++ b/aws/resource_aws_appmesh_virtual_node_test.go
@@ -55,7 +55,8 @@ func testAccAwsAppmeshVirtualNode_cloudMapServiceDiscovery(t *testing.T) {
 	nsResourceName := "aws_service_discovery_http_namespace.test"
 	meshName := fmt.Sprintf("tf-test-mesh-%d", acctest.RandInt())
 	vnName := fmt.Sprintf("tf-test-node-%d", acctest.RandInt())
-	rName := fmt.Sprintf("tf-testacc-appmeshvn-%s", acctest.RandStringFromCharSet(11, acctest.CharSetAlphaNum))
+	// Avoid 'config is invalid: last character of "name" must be a letter' for aws_service_discovery_http_namespace.
+	rName := fmt.Sprintf("tf-testacc-appmeshvn-%s", acctest.RandStringFromCharSet(11, acctest.CharSetAlpha))
 
 	resource.Test(t, resource.TestCase{
 		PreCheck:     func() { testAccPreCheck(t) },
diff --git a/aws/resource_aws_service_discovery_service_test.go b/aws/resource_aws_service_discovery_service_test.go
index 485d69c60fd..79792dc1012 100644
--- a/aws/resource_aws_service_discovery_service_test.go
+++ b/aws/resource_aws_service_discovery_service_test.go
@@ -93,7 +93,7 @@ func TestAccAWSServiceDiscoveryService_public(t *testing.T) {
 }
 
 func TestAccAWSServiceDiscoveryService_http(t *testing.T) {
-	rName := acctest.RandString(5)
+	rName := acctest.RandStringFromCharSet(5, acctest.CharSetAlpha)
 	resourceName := "aws_service_discovery_service.test"
 
 	resource.ParallelTest(t, resource.TestCase{