OpenTofu Variables

Variable precedence

Values are resolved in this order, lowest to highest:

1. Variable defaults (declared in variables.tf)
2. shared.tfvars (passed via -var-file=../shared.tfvars)
3. Provider-specific terraform.tfvars
4. -var flags on the command line
5. TF_VAR_ environment variables

Shared variables

tofu/remote/shared.tfvars holds values that apply to all providers. Both DigitalOcean and GKE declare these variables so neither produces an “undeclared variable” error when OpenTofu loads the shared file.

Variable	Type	Value	Notes
cluster_name	string	"ccafp"	Kubernetes cluster name
registry_name	string	"rs-inc"	Container registry name. Used by DigitalOcean; declared but unused by GKE (see below).

DigitalOcean variables

Defined in tofu/remote/digitalocean/variables.tf.

Cluster

Variable	Type	Default	Description
cluster_name	string	—	Kubernetes cluster name. Required; supplied by shared.tfvars.
region	string	"syd1"	DigitalOcean region slug.
node_size	string	"s-1vcpu-2gb"	Droplet size slug for worker nodes.
node_count	number	3	Initial number of worker nodes.

Autoscaling

Variable	Type	Default	Description
auto_scale	bool	true	Enable cluster autoscaling.
min_nodes	number	2	Minimum nodes when autoscaling.
max_nodes	number	4	Maximum nodes when autoscaling.

Registry

Variable	Type	Default	Description
registry_name	string	"rs-inc"	DigitalOcean container registry name. Overridden by shared.tfvars.

Maintenance window

Variable	Type	Default	Description
maintenance_day	string	"sunday"	Day of week for the maintenance window.
maintenance_start_time	string	"04:00"	Start time (UTC) for the maintenance window.

GKE variables

Defined in tofu/remote/google/variables.tf.

Project and cluster

Variable	Type	Default	Description
project_id	string	null	GCP project ID. Set via TF_VAR_project_id, GOOGLE_PROJECT, or terraform.tfvars.
cluster_name	string	—	GKE cluster name. Required; supplied by shared.tfvars.
region	string	"australia-southeast1"	GCP region.
zone	string	"australia-southeast1-a"	GCP zone. Zonal clusters get a free control plane under the GKE free tier.
deletion_protection	bool	true	Prevent accidental cluster deletion. The CLI destroy command accepts --i-am-sure to override.

Node pool

Variable	Type	Default	Description
machine_type	string	"e2-medium"	Node machine type.
node_count	number	3	Nodes per zone.
spot	bool	true	Use Spot VMs for worker nodes. Reduces cost; nodes may be preempted.
disk_size_gb	number	30	Boot disk size per node in GB.

Autoscaling

Variable	Type	Default	Description
auto_scale	bool	true	Enable node pool autoscaling.
min_nodes	number	1	Minimum nodes when autoscaling.
max_nodes	number	4	Maximum nodes when autoscaling.

Networking

Variable	Type	Default	Description
network_name	string	""	VPC network name. Empty string uses the default network.
subnet_cidr	string	"10.10.0.0/24"	Primary subnet CIDR range.
pod_cidr	string	"10.20.0.0/16"	Secondary IP range for pods.
service_cidr	string	"10.30.0.0/20"	Secondary IP range for services.

Registry

Variable	Type	Default	Description
artifact_registry_id	string	""	Artifact Registry repository ID. GKE uses this instead of registry_name.
registry_name	string	""	Unused by GKE. Declared for shared.tfvars compatibility so OpenTofu does not raise an undeclared variable error.