use the cluster subnet to look up the node cidr block

google/resource_container_cluster.go

@@ -888,7 +888,7 @@ func resourceContainerClusterRead(d *schema.ResourceData, meta interface{}) erro
 		return err
 	}
 
-	if err := d.Set("ip_allocation_policy", flattenIPAllocationPolicy(cluster.IpAllocationPolicy, d, config)); err != nil {
+	if err := d.Set("ip_allocation_policy", flattenIPAllocationPolicy(cluster, d, config)); err != nil {
 		return err
 	}
 
@@ -1783,35 +1783,36 @@ func flattenPrivateClusterConfig(c *containerBeta.PrivateClusterConfig) []map[st
 	}
 }
 
-func flattenIPAllocationPolicy(c *containerBeta.IPAllocationPolicy, d *schema.ResourceData, config *Config) []map[string]interface{} {
-	if c == nil {
+func flattenIPAllocationPolicy(c *containerBeta.Cluster, d *schema.ResourceData, config *Config) []map[string]interface{} {
+	if c == nil || c.IpAllocationPolicy == nil {
 		return nil
 	}
-	node_cidr_block := ""
-	if c.SubnetworkName != "" {
-		subnetwork, err := ParseSubnetworkFieldValue(c.SubnetworkName, d, config)
+	nodeCidrBlock := ""
+	if c.Subnetwork != "" {
+		subnetwork, err := ParseSubnetworkFieldValue(c.Subnetwork, d, config)
 		if err == nil {
 			sn, err := config.clientCompute.Subnetworks.Get(subnetwork.Project, subnetwork.Region, subnetwork.Name).Do()
 			if err == nil {
-				node_cidr_block = sn.IpCidrRange
+				nodeCidrBlock = sn.IpCidrRange
 			}
 		} else {
 			log.Printf("[WARN] Unable to parse subnetwork name, got error while trying to get new subnetwork: %s", err)
 		}
 	}
+	p := c.IpAllocationPolicy
 	return []map[string]interface{}{
 		{
-			"use_ip_aliases": c.UseIpAliases,
+			"use_ip_aliases": p.UseIpAliases,
 
-			"create_subnetwork": c.CreateSubnetwork,
-			"subnetwork_name":   c.SubnetworkName,
+			"create_subnetwork": p.CreateSubnetwork,
+			"subnetwork_name":   p.SubnetworkName,
 
-			"cluster_ipv4_cidr_block":  c.ClusterIpv4CidrBlock,
-			"services_ipv4_cidr_block": c.ServicesIpv4CidrBlock,
-			"node_ipv4_cidr_block":     node_cidr_block,
+			"cluster_ipv4_cidr_block":  p.ClusterIpv4CidrBlock,
+			"services_ipv4_cidr_block": p.ServicesIpv4CidrBlock,
+			"node_ipv4_cidr_block":     nodeCidrBlock,
 
-			"cluster_secondary_range_name":  c.ClusterSecondaryRangeName,
-			"services_secondary_range_name": c.ServicesSecondaryRangeName,
+			"cluster_secondary_range_name":  p.ClusterSecondaryRangeName,
+			"services_secondary_range_name": p.ServicesSecondaryRangeName,
 		},
 	}
 }

google/resource_container_cluster_test.go

@@ -2260,22 +2260,15 @@ resource "google_compute_network" "container_network" {
 	auto_create_subnetworks = false
 }
 
-resource "google_compute_subnetwork" "container_subnetwork" {
-	name		  = "${google_compute_network.container_network.name}"
-	network		  = "${google_compute_network.container_network.name}"
-	ip_cidr_range = "10.128.0.0/9"
-	region		  = "us-central1"
-}
-
 resource "google_container_cluster" "with_ip_allocation_policy" {
 	name	   = "%s"
 	zone	   = "us-central1-a"
 	network    = "${google_compute_network.container_network.name}"
-	subnetwork = "${google_compute_subnetwork.container_subnetwork.name}"
 
 	initial_node_count = 1
 	ip_allocation_policy {
 		use_ip_aliases           = true
+		create_subnetwork        = true
 		cluster_ipv4_cidr_block  = "10.0.0.0/16"
 		services_ipv4_cidr_block = "10.1.0.0/16"
 		node_ipv4_cidr_block     = "10.2.0.0/16"

website/docs/r/container_cluster.html.markdown

@@ -416,6 +416,7 @@ API is `false`; afterwards, it's `true`.
     pick a specific range to use.
 
 * `node_ipv4_cidr_block` - (Optional) The IP address range of the node IPs in this cluster.
+    This should be set only if `create_subnetwork` is true.
     Set to blank to have a range chosen with the default size. Set to /netmask (e.g. /14)
     to have a range chosen with a specific netmask. Set to a CIDR notation (e.g. 10.96.0.0/14)
     from the RFC-1918 private networks (e.g. 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to