googlecloudsdk.calliope.exceptions.HttpException: ResponseError: code=400, message=Autopilot clusters must be regional clusters.

Problem

Trying to create an auto-cluster either using terraform or gcloud cli, and specifying the region name returns the error that ‘Autopilot clusters must be regional clusters.

So with gcloud this is the command and output

kosmas: (master %%)$ gcloud container clusters create-auto test-cluster --region=europe-west6-b
Note: The Pod address range limits the maximum size of the cluster. Please refer to https://cloud.google.com/kubernetes-engine/docs/how-to/flexible-pod-cidr to learn how to optimize IP address allocation.
ERROR: (gcloud.container.clusters.create-auto) ResponseError: code=400, message=Autopilot clusters must be regional clusters.

Solution

Using the actual region name (that can be taken from the list of available zones/regions)

gcloud compute zones list

NAME                       REGION                   STATUS  NEXT_MAINTENANCE  TURNDOWN_DATE
us-east1-b                 us-east1                 UP
us-east1-c                 us-east1                 UP
...
europe-west6-b             europe-west6             UP
...

And using the correct region name (without the b)

gcloud container clusters create-auto test-cluster --region=europe-west6 --verbosity debug

...
Created [https://container.googleapis.com/v1/projects/gitlab-runner-343714/zones/europe-west6/clusters/test-cluster].
...
NAME          LOCATION      MASTER_VERSION   MASTER_IP     MACHINE_TYPE  NODE_VERSION     NUM_NODES  STATUS
test-cluster  europe-west6  1.21.6-gke.1503  xxx.xxx.xxx.xxx  e2-medium     1.21.6-gke.1503  3          RUNNING