Machine Locations

This document describes how to configure the location of a CAPG cluster’s compute resources. By default, CAPG requires the user to specify a GCP region for the cluster’s machines by setting the GCP_REGION environment variable as outlined in the CAPI quickstart guide. The provider then picks a zone to deploy the control plane and worker nodes in and generates the according portions of the cluster’s YAML manifests.

It is possible to override this default behaviour and exercise more fine-grained control over machine locations as outlined in the rest of this document.

Control Plane Machine Location

Before deploying the cluster, add a failureDomains field to the spec of your GCPCluster definition, containing a list of allowed zones:

apiVersion: infrastructure.cluster.x-k8s.io/v1alpha4
kind: GCPCluster
metadata:
  name: capi-quickstart
spec:
  network:
    name: default
  project: cyberscan2
  region: europe-west3
+  failureDomains:
+    - europe-west3-b

In this example configuration, only a single zone has been added, ensuring the control plane is provisioned in europe-west3-b.

Node Pool Location

Similar to the above, you can override the auto-generated GCP zone for your MachineDeployment, by changing the value of the failureDomain field at spec.template.spec.failureDomain:

apiVersion: cluster.x-k8s.io/v1alpha4
kind: MachineDeployment
metadata:
  name: capi-quickstart-md-0
spec:
  clusterName: capi-quickstart
  # [...]
  template:
    spec:
      # [...]
      clusterName: capi-quickstart
-      failureDomain: europe-west3-a
+      failureDomain: europe-west3-b

When combined like this, the above configuration effectively instructs CAPG to deploy the CAPI equivalent of a zonal GKE cluster.

Placement policies

To attach an existing Compute Engine placement policy at instance creation, set resourcePolicies in the GCPMachineTemplate referenced by the worker MachineDeployment (or by the control plane):

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: GCPMachineTemplate
metadata:
  name: workers-with-placement
spec:
  template:
    spec:
      instanceType: n2-standard-2
      resourcePolicies:
        - projects/my-project/regions/us-central1/resourcePolicies/my-spread-policy

The policy must already exist in the same region as the VM. Full resource URLs are also accepted. CAPG attaches the policy in the instance creation request; Google Cloud validates policy compatibility and chooses placement. CAPG does not create or delete the referenced policy, or set Kubernetes node placement labels.

This is creation-time configuration. To change the policy, create a new machine template and roll out replacement machines; editing an existing GCPMachine spec is not supported. Omitting resourcePolicies preserves the existing behavior of creating an instance without an explicitly configured policy.