feat: add compact placement feature for node pools

Use a compact placement policy to specify that nodes within the node pool should be placed in closer physical proximity to each other within a zone. Having nodes closer to each other can reduce network latency between nodes, which can be useful for tightly-coupled batch workloads.

PiperOrigin-RevId: 488490422

google/container/v1/cluster_service.proto

@@ -2994,6 +2994,23 @@ message NodePool {
     ERROR = 6;
   }
 
+  // PlacementPolicy defines the placement policy used by the node pool.
+  message PlacementPolicy {
+    // Type defines the type of placement policy.
+    enum Type {
+      // TYPE_UNSPECIFIED specifies no requirements on nodes
+      // placement.
+      TYPE_UNSPECIFIED = 0;
+
+      // COMPACT specifies node placement in the same availability domain to
+      // ensure low communication latency.
+      COMPACT = 1;
+    }
+
+    // The type of placement.
+    Type type = 1;
+  }
+
   // The name of the node pool.
   string name = 1;
 
@@ -3063,6 +3080,9 @@ message NodePool {
   // Upgrade settings control disruption and speed of the upgrade.
   UpgradeSettings upgrade_settings = 107;
 
+  // Specifies the node placement policy.
+  PlacementPolicy placement_policy = 108;
+
   // Output only. [Output only] Update info contains relevant information during a node
   // pool update.
   UpdateInfo update_info = 109 [(google.api.field_behavior) = OUTPUT_ONLY];