I got an error trying to start a new Hail cluster

I ran hailctl dataproc start test and received this error:

ERROR: (gcloud.dataproc.clusters.create) Error parsing [cluster].
The [cluster] resource is not properly specified.
Failed to find attribute [region]. The attribute can be set in the following ways:
 - provide the argument [--region] on the command line
 - set the property [dataproc/region]

What should I do?

As of gcloud 277.0.0 (2020-01-21), Dataproc clusters require an explicit region:

277.0.0 (2020-01-21)
  Breaking Changes
      ▪ **(App Engine)** Fixed longstanding issue where /path in
        dispatch.yaml was silently converted to /path/.
      ▪ **(Cloud Dataproc)**
      ▪ **(Cloud Dataproc)** Modified --region flag to be mandatory.
        ◆ To use Cloud Dataproc commands, pass --region flag on every
          invocation, or set dataproc/region configuration variable via gcloud
          config set dataproc/region.

Simply set a default dataproc region on every computer that you use, for example:

gcloud config set dataproc/region us-central1

Note that a region is more broad than a zone: us-central1 is a region, us-central1-a is a zone.

With this change, some dataproc resources that were created before may be in the global region.

If you are not seeing resources that you expect, like autoscaling policies, after setting the region argument, retry your command with --region global and see if that makes a difference.