feat(client-auto-scaling): Auto Scaling groups now support the ability to strictly balance instances across Availability Zones by configuring the AvailabilityZoneDistribution parameter. If balanced-only is configured for a group, launches will always be attempted in the under scaled Availability Zone even if it is unhealthy.

Author: awstools

clients/client-auto-scaling/src/commands/CreateAutoScalingGroupCommand.ts

@@ -208,6 +208,9 @@ export interface CreateAutoScalingGroupCommandOutput extends __MetadataBearer {}
  *     MinHealthyPercentage: Number("int"),
  *     MaxHealthyPercentage: Number("int"),
  *   },
+ *   AvailabilityZoneDistribution: { // AvailabilityZoneDistribution
+ *     CapacityDistributionStrategy: "balanced-only" || "balanced-best-effort",
+ *   },
  * };
  * const command = new CreateAutoScalingGroupCommand(input);
  * const response = await client.send(command);

clients/client-auto-scaling/src/commands/DescribeAutoScalingGroupsCommand.ts

@@ -247,6 +247,9 @@ export interface DescribeAutoScalingGroupsCommandOutput extends AutoScalingGroup
  * //         MinHealthyPercentage: Number("int"),
  * //         MaxHealthyPercentage: Number("int"),
  * //       },
+ * //       AvailabilityZoneDistribution: { // AvailabilityZoneDistribution
+ * //         CapacityDistributionStrategy: "balanced-only" || "balanced-best-effort",
+ * //       },
  * //     },
  * //   ],
  * //   NextToken: "STRING_VALUE",

clients/client-auto-scaling/src/commands/UpdateAutoScalingGroupCommand.ts

@@ -204,6 +204,9 @@ export interface UpdateAutoScalingGroupCommandOutput extends __MetadataBearer {}
  *     MinHealthyPercentage: Number("int"),
  *     MaxHealthyPercentage: Number("int"),
  *   },
+ *   AvailabilityZoneDistribution: { // AvailabilityZoneDistribution
+ *     CapacityDistributionStrategy: "balanced-only" || "balanced-best-effort",
+ *   },
  * };
  * const command = new UpdateAutoScalingGroupCommand(input);
  * const response = await client.send(command);

clients/client-auto-scaling/src/models/models_0.ts

@@ -744,6 +744,46 @@ export interface CompleteLifecycleActionType {
   InstanceId?: string;
 }
 
+/**
+ * @public
+ * @enum
+ */
+export const CapacityDistributionStrategy = {
+  BALANCED_BEST_EFFORT: "balanced-best-effort",
+  BALANCED_ONLY: "balanced-only",
+} as const;
+
+/**
+ * @public
+ */
+export type CapacityDistributionStrategy =
+  (typeof CapacityDistributionStrategy)[keyof typeof CapacityDistributionStrategy];
+
+/**
+ * <p>
+ *             Describes an Availability Zone distribution.
+ *         </p>
+ * @public
+ */
+export interface AvailabilityZoneDistribution {
+  /**
+   * <p>
+   *             If launches fail in an Availability Zone, the following strategies are available. The default is <code>balanced-best-effort</code>. </p>
+   *          <ul>
+   *             <li>
+   *                <p>
+   *                   <code>balanced-only</code> - If launches fail in an Availability Zone, Auto Scaling will continue to attempt to launch in the unhealthy zone to preserve a balanced distribution.</p>
+   *             </li>
+   *             <li>
+   *                <p>
+   *                   <code>balanced-best-effort</code> - If launches fail in an Availability Zone, Auto Scaling will attempt to launch in another healthy Availability Zone instead.</p>
+   *             </li>
+   *          </ul>
+   * @public
+   */
+  CapacityDistributionStrategy?: CapacityDistributionStrategy;
+}
+
 /**
  * <p>Describes an instance maintenance policy.</p>
  *          <p>For more information, see <a href="https://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-instance-maintenance-policy.html">Set instance maintenance policy</a> in the
@@ -2103,6 +2143,12 @@ export interface CreateAutoScalingGroupType {
    * @public
    */
   InstanceMaintenancePolicy?: InstanceMaintenancePolicy;
+
+  /**
+   * <p>The instance capacity distribution across Availability Zones.</p>
+   * @public
+   */
+  AvailabilityZoneDistribution?: AvailabilityZoneDistribution;
 }
 
 /**
@@ -3481,6 +3527,14 @@ export interface AutoScalingGroup {
    * @public
    */
   InstanceMaintenancePolicy?: InstanceMaintenancePolicy;
+
+  /**
+   * <p>
+   *             The instance capacity distribution across Availability Zones.
+   *         </p>
+   * @public
+   */
+  AvailabilityZoneDistribution?: AvailabilityZoneDistribution;
 }
 
 /**
@@ -8241,4 +8295,12 @@ export interface UpdateAutoScalingGroupType {
    * @public
    */
   InstanceMaintenancePolicy?: InstanceMaintenancePolicy;
+
+  /**
+   * <p>
+   *             The instance capacity distribution across Availability Zones.
+   *         </p>
+   * @public
+   */
+  AvailabilityZoneDistribution?: AvailabilityZoneDistribution;
 }

clients/client-auto-scaling/src/protocols/Aws_query.ts

@@ -253,6 +253,7 @@ import {
   AutoScalingGroupsType,
   AutoScalingInstanceDetails,
   AutoScalingInstancesType,
+  AvailabilityZoneDistribution,
   BaselineEbsBandwidthMbpsRequest,
   BatchDeleteScheduledActionAnswer,
   BatchDeleteScheduledActionType,
@@ -3248,6 +3249,17 @@ const se_AutoScalingNotificationTypes = (input: string[], context: __SerdeContex
   return entries;
 };
 
+/**
+ * serializeAws_queryAvailabilityZoneDistribution
+ */
+const se_AvailabilityZoneDistribution = (input: AvailabilityZoneDistribution, context: __SerdeContext): any => {
+  const entries: any = {};
+  if (input[_CDS] != null) {
+    entries[_CDS] = input[_CDS];
+  }
+  return entries;
+};
+
 /**
  * serializeAws_queryAvailabilityZones
  */
@@ -3598,6 +3610,13 @@ const se_CreateAutoScalingGroupType = (input: CreateAutoScalingGroupType, contex
       entries[loc] = value;
     });
   }
+  if (input[_AZD] != null) {
+    const memberEntries = se_AvailabilityZoneDistribution(input[_AZD], context);
+    Object.entries(memberEntries).forEach(([key, value]) => {
+      const loc = `AvailabilityZoneDistribution.${key}`;
+      entries[loc] = value;
+    });
+  }
   return entries;
 };
 
@@ -6359,6 +6378,13 @@ const se_UpdateAutoScalingGroupType = (input: UpdateAutoScalingGroupType, contex
       entries[loc] = value;
     });
   }
+  if (input[_AZD] != null) {
+    const memberEntries = se_AvailabilityZoneDistribution(input[_AZD], context);
+    Object.entries(memberEntries).forEach(([key, value]) => {
+      const loc = `AvailabilityZoneDistribution.${key}`;
+      entries[loc] = value;
+    });
+  }
   return entries;
 };
 
@@ -6800,6 +6826,9 @@ const de_AutoScalingGroup = (output: any, context: __SerdeContext): AutoScalingG
   if (output[_IMP] != null) {
     contents[_IMP] = de_InstanceMaintenancePolicy(output[_IMP], context);
   }
+  if (output[_AZD] != null) {
+    contents[_AZD] = de_AvailabilityZoneDistribution(output[_AZD], context);
+  }
   return contents;
 };
 
@@ -6906,6 +6935,17 @@ const de_AutoScalingNotificationTypes = (output: any, context: __SerdeContext):
     });
 };
 
+/**
+ * deserializeAws_queryAvailabilityZoneDistribution
+ */
+const de_AvailabilityZoneDistribution = (output: any, context: __SerdeContext): AvailabilityZoneDistribution => {
+  const contents: any = {};
+  if (output[_CDS] != null) {
+    contents[_CDS] = __expectString(output[_CDS]);
+  }
+  return contents;
+};
+
 /**
  * deserializeAws_queryAvailabilityZones
  */
@@ -9425,6 +9465,7 @@ const _ATS = "AttachTrafficSources";
 const _ATd = "AdjustmentType";
 const _ATdj = "AdjustmentTypes";
 const _AZ = "AvailabilityZones";
+const _AZD = "AvailabilityZoneDistribution";
 const _AZv = "AvailabilityZone";
 const _Ac = "Activities";
 const _Act = "Activity";
@@ -9441,6 +9482,7 @@ const _C = "Context";
 const _CASG = "CreateAutoScalingGroup";
 const _CCMS = "CustomizedCapacityMetricSpecification";
 const _CD = "CheckpointDelay";
+const _CDS = "CapacityDistributionStrategy";
 const _CF = "CapacityForecast";
 const _CIR = "CancelInstanceRefresh";
 const _CLA = "CompleteLifecycleAction";

codegen/sdk-codegen/aws-models/auto-scaling.json

@@ -918,6 +918,12 @@
           "traits": {
             "smithy.api#documentation": "<p>An instance maintenance policy.</p>"
           }
+        },
+        "AvailabilityZoneDistribution": {
+          "target": "com.amazonaws.autoscaling#AvailabilityZoneDistribution",
+          "traits": {
+            "smithy.api#documentation": "<p>\n            The instance capacity distribution across Availability Zones.\n        </p>"
+          }
         }
       },
       "traits": {
@@ -2299,6 +2305,20 @@
         }
       }
     },
+    "com.amazonaws.autoscaling#AvailabilityZoneDistribution": {
+      "type": "structure",
+      "members": {
+        "CapacityDistributionStrategy": {
+          "target": "com.amazonaws.autoscaling#CapacityDistributionStrategy",
+          "traits": {
+            "smithy.api#documentation": "<p>\n            If launches fail in an Availability Zone, the following strategies are available. The default is <code>balanced-best-effort</code>. </p>\n         <ul>\n            <li>\n               <p>\n                  <code>balanced-only</code> - If launches fail in an Availability Zone, Auto Scaling will continue to attempt to launch in the unhealthy zone to preserve a balanced distribution.</p>\n            </li>\n            <li>\n               <p>\n                  <code>balanced-best-effort</code> - If launches fail in an Availability Zone, Auto Scaling will attempt to launch in another healthy Availability Zone instead.</p>\n            </li>\n         </ul>"
+          }
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>\n            Describes an Availability Zone distribution.\n        </p>"
+      }
+    },
     "com.amazonaws.autoscaling#AvailabilityZones": {
       "type": "list",
       "member": {
@@ -2625,6 +2645,23 @@
         }
       }
     },
+    "com.amazonaws.autoscaling#CapacityDistributionStrategy": {
+      "type": "enum",
+      "members": {
+        "BALANCED_ONLY": {
+          "target": "smithy.api#Unit",
+          "traits": {
+            "smithy.api#enumValue": "balanced-only"
+          }
+        },
+        "BALANCED_BEST_EFFORT": {
+          "target": "smithy.api#Unit",
+          "traits": {
+            "smithy.api#enumValue": "balanced-best-effort"
+          }
+        }
+      }
+    },
     "com.amazonaws.autoscaling#CapacityForecast": {
       "type": "structure",
       "members": {
@@ -3098,6 +3135,12 @@
           "traits": {
             "smithy.api#documentation": "<p>An instance maintenance policy. For more information, see <a href=\"https://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-instance-maintenance-policy.html\">Set instance maintenance policy</a> in the\n            <i>Amazon EC2 Auto Scaling User Guide</i>.</p>"
           }
+        },
+        "AvailabilityZoneDistribution": {
+          "target": "com.amazonaws.autoscaling#AvailabilityZoneDistribution",
+          "traits": {
+            "smithy.api#documentation": "<p>The instance capacity distribution across Availability Zones.</p>"
+          }
         }
       }
     },
@@ -10912,6 +10955,12 @@
           "traits": {
             "smithy.api#documentation": "<p>An instance maintenance policy. For more information, see <a href=\"https://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-instance-maintenance-policy.html\">Set instance maintenance policy</a> in the\n            <i>Amazon EC2 Auto Scaling User Guide</i>.</p>"
           }
+        },
+        "AvailabilityZoneDistribution": {
+          "target": "com.amazonaws.autoscaling#AvailabilityZoneDistribution",
+          "traits": {
+            "smithy.api#documentation": "<p>\n            The instance capacity distribution across Availability Zones.\n        </p>"
+          }
         }
       }
     },