Replace target tracking scaling with simple scaling

Using simple scaling should allow us to utilise https://docs.aws.amazon.com/cli/latest/reference/autoscaling/execute-policy.html to test behaviour more deterministically.
guardian · Sep 2, 2024 · f13e703 · f13e703
1 parent e990c09
commit f13e703
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Showing 2 changed files with 72 additions and 76 deletions.
diff --git a/packages/cdk/lib/__snapshots__/scaling-asg-rolling-update.test.ts.snap b/packages/cdk/lib/__snapshots__/scaling-asg-rolling-update.test.ts.snap
@@ -29,6 +29,11 @@ exports[`The ScalingAsgRollingUpdate stack matches the snapshot 1`] = `
     "gu:cdk:version": "TEST",
   },
   "Outputs": {
+    "AutoscalingGroupName": {
+      "Value": {
+        "Ref": "AutoScalingGroupScalingASG8AF02C37",
+      },
+    },
     "LoadBalancerScalingDnsName": {
       "Description": "DNS entry for LoadBalancerScaling",
       "Value": {
@@ -38,6 +43,22 @@ exports[`The ScalingAsgRollingUpdate stack matches the snapshot 1`] = `
         ],
       },
     },
+    "ScaleInArn": {
+      "Value": {
+        "Fn::GetAtt": [
+          "ScaleIn",
+          "Arn",
+        ],
+      },
+    },
+    "ScaleOutArn": {
+      "Value": {
+        "Fn::GetAtt": [
+          "ScaleOut",
+          "Arn",
+        ],
+      },
+    },
   },
   "Parameters": {
     "AMIScaling": {
@@ -192,79 +213,6 @@ exports[`The ScalingAsgRollingUpdate stack matches the snapshot 1`] = `
         },
       },
     },
-    "AutoScalingGroupScalingScalingPolicyScaleOnRequest26CCAA7B": {
-      "DependsOn": [
-        "ListenerScaling76B5CBA7",
-      ],
-      "Properties": {
-        "AutoScalingGroupName": {
-          "Ref": "AutoScalingGroupScalingASG8AF02C37",
-        },
-        "PolicyType": "TargetTrackingScaling",
-        "TargetTrackingConfiguration": {
-          "PredefinedMetricSpecification": {
-            "PredefinedMetricType": "ALBRequestCountPerTarget",
-            "ResourceLabel": {
-              "Fn::Join": [
-                "",
-                [
-                  {
-                    "Fn::Select": [
-                      1,
-                      {
-                        "Fn::Split": [
-                          "/",
-                          {
-                            "Ref": "ListenerScaling76B5CBA7",
-                          },
-                        ],
-                      },
-                    ],
-                  },
-                  "/",
-                  {
-                    "Fn::Select": [
-                      2,
-                      {
-                        "Fn::Split": [
-                          "/",
-                          {
-                            "Ref": "ListenerScaling76B5CBA7",
-                          },
-                        ],
-                      },
-                    ],
-                  },
-                  "/",
-                  {
-                    "Fn::Select": [
-                      3,
-                      {
-                        "Fn::Split": [
-                          "/",
-                          {
-                            "Ref": "ListenerScaling76B5CBA7",
-                          },
-                        ],
-                      },
-                    ],
-                  },
-                  "/",
-                  {
-                    "Fn::GetAtt": [
-                      "TargetGroupScalingFC90421F",
-                      "TargetGroupFullName",
-                    ],
-                  },
-                ],
-              ],
-            },
-          },
-          "TargetValue": 5,
-        },
-      },
-      "Type": "AWS::AutoScaling::ScalingPolicy",
-    },
     "CertificateScaling767DD870": {
       "DeletionPolicy": "Retain",
       "Properties": {
@@ -727,6 +675,28 @@ exports[`The ScalingAsgRollingUpdate stack matches the snapshot 1`] = `
       },
       "Type": "AWS::IAM::Policy",
     },
+    "ScaleIn": {
+      "Properties": {
+        "AdjustmentType": "ChangeInCapacity",
+        "AutoScalingGroupName": {
+          "Ref": "AutoScalingGroupScalingASG8AF02C37",
+        },
+        "PolicyType": "SimpleScaling",
+        "ScalingAdjustment": -1,
+      },
+      "Type": "AWS::AutoScaling::ScalingPolicy",
+    },
+    "ScaleOut": {
+      "Properties": {
+        "AdjustmentType": "ChangeInCapacity",
+        "AutoScalingGroupName": {
+          "Ref": "AutoScalingGroupScalingASG8AF02C37",
+        },
+        "PolicyType": "SimpleScaling",
+        "ScalingAdjustment": 1,
+      },
+      "Type": "AWS::AutoScaling::ScalingPolicy",
+    },
     "SsmSshPolicy4CFC977E": {
       "Properties": {
         "PolicyDocument": {

diff --git a/packages/cdk/lib/scaling-asg-rolling-update.ts b/packages/cdk/lib/scaling-asg-rolling-update.ts
@@ -3,8 +3,9 @@ import { GuStack } from '@guardian/cdk/lib/constructs/core';
 import { GuCname } from '@guardian/cdk/lib/constructs/dns';
 import { GuEc2AppExperimental } from '@guardian/cdk/lib/experimental/patterns/ec2-app';
 import type { App } from 'aws-cdk-lib';
-import { Duration, Tags } from 'aws-cdk-lib';
+import { CfnOutput, Duration, Tags } from 'aws-cdk-lib';
 import type { CfnAutoScalingGroup } from 'aws-cdk-lib/aws-autoscaling';
+import { CfnScalingPolicy } from 'aws-cdk-lib/aws-autoscaling';
 import { InstanceClass, InstanceSize, InstanceType } from 'aws-cdk-lib/aws-ec2';
 
 interface ScalingAsgRollingUpdateProps {
@@ -61,8 +62,33 @@ export class ScalingAsgRollingUpdate extends GuStack {
 			'testing-asg-rolling-update.service',
 		);
 
-		autoScalingGroup.scaleOnRequestCount('ScaleOnRequest', {
-			targetRequestsPerMinute: 5,
+		const scaleOutPolicy = new CfnScalingPolicy(this, 'ScaleOut', {
+			autoScalingGroupName: autoScalingGroup.autoScalingGroupName,
+			policyType: 'SimpleScaling',
+			adjustmentType: 'ChangeInCapacity',
+			scalingAdjustment: 1,
+		});
+
+		const scaleInPolicy = new CfnScalingPolicy(this, 'ScaleIn', {
+			autoScalingGroupName: autoScalingGroup.autoScalingGroupName,
+			policyType: 'SimpleScaling',
+			adjustmentType: 'ChangeInCapacity',
+			scalingAdjustment: -1,
+		});
+
+		new CfnOutput(this, 'ScaleOutArn', {
+			key: 'ScaleOutArn',
+			value: scaleOutPolicy.attrArn,
+		});
+
+		new CfnOutput(this, 'ScaleInArn', {
+			key: 'ScaleInArn',
+			value: scaleInPolicy.attrArn,
+		});
+
+		new CfnOutput(this, 'AutoscalingGroupName', {
+			key: 'AutoscalingGroupName',
+			value: autoScalingGroup.autoScalingGroupName,
 		});
 
 		const cfnAsg = autoScalingGroup.node.defaultChild as CfnAutoScalingGroup;