Add support for node_locations to google_container_node_pool. (#4478)

Signed-off-by: Modular Magician <magic-modules@google.com>

website/docs/r/container_cluster.html.markdown

@@ -129,11 +129,9 @@ throughout the region. `region` has been deprecated in favour of `location`.
 the provider zone is used to create a zonal cluster.
 
 * `node_locations` - (Optional) The list of zones in which the cluster's nodes
-should be located. These must be in the same region as the cluster zone for
-zonal clusters, or in the region of a regional cluster. In a multi-zonal cluster,
-the number of nodes specified in `initial_node_count` is created in
-all specified zones as well as the primary zone. If specified for a regional
-cluster, nodes will be created in only these zones.
+are located. Nodes must be in the region of their regional cluster or in the
+same region as their cluster's zone for zonal clusters. If this is specified for
+a zonal cluster, omit the cluster's zone.
 
 -> A "multi-zonal" cluster is a zonal cluster with at least one additional zone
 defined; in a multi-zonal cluster, the cluster master is only present in a
@@ -194,10 +192,11 @@ for more details. Structure is documented below.
     Defaults to `false`
 
 * `initial_node_count` - (Optional) The number of nodes to create in this
-    cluster's default node pool. Must be set if `node_pool` is not set. If
-    you're using `google_container_node_pool` objects with no default node pool,
-    you'll need to set this to a value of at least `1`, alongside setting
-    `remove_default_node_pool` to `true`.
+cluster's default node pool. In regional or multi-zonal clusters, this is the
+number of nodes per zone. Must be set if `node_pool` is not set. If you're using
+`google_container_node_pool` objects with no default node pool, you'll need to
+set this to a value of at least `1`, alongside setting
+`remove_default_node_pool` to `true`.
 
 * `ip_allocation_policy` - (Optional) Configuration for cluster IP allocation. As of now, only pre-allocated subnetworks (custom type with secondary ranges) are supported.
     This will activate IP aliases. See the [official documentation](https://cloud.google.com/kubernetes-engine/docs/how-to/ip-aliases)

website/docs/r/container_node_pool.html.markdown

@@ -98,12 +98,11 @@ resource "google_container_cluster" "primary" {
 
 ## Argument Reference
 
-* `cluster` - (Required) The cluster to create the node pool for.  Cluster must be present in `zone` provided for zonal clusters.
+* `cluster` - (Required) The cluster to create the node pool for. Cluster must be present in `zone` provided for zonal clusters.
 
 - - -
 
-* `location` - (Optional) The location (region or zone) in which the cluster
-resides.
+* `location` - (Optional) The location (region or zone) of the cluster.
 
 * `zone` - (Optional, Deprecated) The zone in which the cluster resides. `zone`
 has been deprecated in favor of `location`.
@@ -119,8 +118,9 @@ type-specific `region` for regional clusters / `zone` for zonal clusters.
 * `autoscaling` - (Optional) Configuration required by cluster autoscaler to adjust
     the size of the node pool to the current cluster usage. Structure is documented below.
 
-* `initial_node_count` - (Optional) The initial node count for the pool. Changing this will force
-    recreation of the resource.
+* `initial_node_count` - (Optional) The initial number of nodes for the pool. In
+regional or multi-zonal clusters, this is the number of nodes per zone. Changing
+this will force recreation of the resource.
 
 * `management` - (Optional) Node management configuration, wherein auto-repair and
     auto-upgrade is configured. Structure is documented below.
@@ -131,6 +131,16 @@ type-specific `region` for regional clusters / `zone` for zonal clusters.
     See the [official documentation](https://cloud.google.com/kubernetes-engine/docs/how-to/flexible-pod-cidr)
     for more information.
 
+* `node_locations` - (Optional, [Beta](https://terraform.io/docs/providers/google/provider_versions.html))
+The list of zones in which the node pool's nodes should be located. Nodes must
+be in the region of their regional cluster or in the same region as their
+cluster's zone for zonal clusters. If unspecified, the cluster-level
+`node_locations` will be used.
+
+-> Note: `node_locations` will not revert to the cluster's default set of zones
+upon being unset. You must manually reconcile the list of zones with your
+cluster.
+
 * `name` - (Optional) The name of the node pool. If left blank, Terraform will
     auto-generate a unique name.