diff --git a/modules/dataproc/README.md b/modules/dataproc/README.md
index d3aa303a1f..2ae54a2346 100644
--- a/modules/dataproc/README.md
+++ b/modules/dataproc/README.md
@@ -260,7 +260,7 @@ module "processing-dp-cluster" {
| [name](variables.tf#L191) | Cluster name. | string
| ✓ | |
| [project_id](variables.tf#L196) | Project ID. | string
| ✓ | |
| [region](variables.tf#L201) | Dataproc region. | string
| ✓ | |
-| [dataproc_config](variables.tf#L17) | Dataproc cluster config. | object({…})
| | {}
|
+| [dataproc_config](variables.tf#L17) | Dataproc cluster config. | object({…})
| | {}
|
| [iam](variables-iam.tf#L24) | IAM bindings in {ROLE => [MEMBERS]} format. | map(list(string))
| | {}
|
| [iam_bindings](variables-iam.tf#L31) | Authoritative IAM bindings in {KEY => {role = ROLE, members = [], condition = {}}}. Keys are arbitrary. | map(object({…}))
| | {}
|
| [iam_bindings_additive](variables-iam.tf#L46) | Individual additive IAM bindings. Keys are arbitrary. | map(object({…}))
| | {}
|
diff --git a/modules/dataproc/variables.tf b/modules/dataproc/variables.tf
index a8164aaf24..371c6b449f 100644
--- a/modules/dataproc/variables.tf
+++ b/modules/dataproc/variables.tf
@@ -47,9 +47,9 @@ variable "dataproc_config" {
}))
master_config = optional(object({
num_instances = number
- machine_type = string
- min_cpu_platform = string
- image_uri = string
+ machine_type = optional(string)
+ min_cpu_platform = optional(string)
+ image_uri = optional(string)
disk_config = optional(object({
boot_disk_type = string
boot_disk_size_gb = number