Use Datastore Cluster name as input rather than a single datastore.

[petervansickel]

The Datastore cluster has multiple datastores associated with it and the ESX layer will determine the best place to assign the storage within the datastore cluster. Victor Havard and Stu Lipshires had a dialog on this in the #infrastructure Slack channel (see link below). The first time I tried to use the terraform for vmware I provided a datastore cluster name for the datastore parameter. Once I found out that fails, I drilled down to the datastore layer in vCenter and picked one that had the most space available. That seems less than ideal, particularly when an ICP cluster needs a large chunk of storage.

See thread in Slack channel: https://ibmcase.slack.com/archives/C5BLKUFGF/p1547742072090600

[petervansickel]

I forgot to add, Stu did some looking and the terraform VMware provisioner supports a datastore_cluster parameter. https://www.terraform.io/docs/providers/vsphere/d/datastore_cluster.html