*`failover_ratio` - (Optional) Ratio (0 to 1) of failed nodes before using the
backup pool (which must also be set).
*`health_checks` - (Optional) List of zero or one healthcheck names.
*`instances` - (Optional) List of instances in the pool. They can be given as
URLs, or in the form of "zone/name". Note that the instances need not exist
at the time of target pool creation, so there is no need to use the Terraform
interpolators to create a dependency on the instances from the target pool.
*`name` - (Required) A unique name for the resource, required by GCE. Changing
this forces a new resource to be created.
*`session_affinity` - (Optional) How to distribute load. Options are "NONE" (no affinity). "CLIENT\_IP" (hash of the source/dest addresses / ports), and "CLIENT\_IP\_PROTO" also includes the protocol (default "NONE").