Merge pull request #5 from TwinProduction/mixed-instance-policy-overr…

…ides

Classify instance as outdated if instance type is no longer part of MixedInstancePolicy's instance types overrides

README.md

@@ -20,6 +20,17 @@ be spun up before draining the old nodes. This is much better, because simply us
 completely useless in the event that the ASG's update on the launch configuration/template is a change of instance type.
 
 
+## Behavior
+
+On interval, this application:
+1. Iterates over each ASG defined by the `AUTO_SCALING_GROUP_NAMES` environment variable
+2. Iterates over each instances of each ASGs
+3. Checks if there's any instances with an outdated launch template version
+4. **If ASG uses MixedInstancesPolicy**, checks if there's any instances with an instance type that isn't part of the list of instance type overrides
+5. Checks if there's any instances with an outdated launch configuration
+6. If any of the conditions defined in the step 3, 4 or 5 are met for any instance, begin the rolling update process for that instance
+
+
 ## Usage
 
 | Environment variable | Description | Required | Default |

cloudtest/cloudtest.go

@@ -100,7 +100,7 @@ func (m *MockAutoScalingService) UpdateAutoScalingGroup(_ *autoscaling.UpdateAut
 	return &autoscaling.UpdateAutoScalingGroupOutput{}, nil
 }
 
-func CreateTestAutoScalingGroup(name, launchConfigurationName string, launchTemplateSpecification *autoscaling.LaunchTemplateSpecification, instances []*autoscaling.Instance) *autoscaling.Group {
+func CreateTestAutoScalingGroup(name, launchConfigurationName string, launchTemplateSpecification *autoscaling.LaunchTemplateSpecification, instances []*autoscaling.Instance, withMixedInstancesPolicy bool) *autoscaling.Group {
 	asg := &autoscaling.Group{
 		AutoScalingGroupName: aws.String(name),
 		Instances:            instances,
@@ -111,8 +111,21 @@ func CreateTestAutoScalingGroup(name, launchConfigurationName string, launchTemp
 	if len(launchConfigurationName) != 0 {
 		asg.SetLaunchConfigurationName(launchConfigurationName)
 	}
-	if launchTemplateSpecification != nil {
-		asg.SetLaunchTemplate(launchTemplateSpecification)
+	if withMixedInstancesPolicy {
+		asg.SetMixedInstancesPolicy(&autoscaling.MixedInstancesPolicy{
+			LaunchTemplate: &autoscaling.LaunchTemplate{
+				LaunchTemplateSpecification: launchTemplateSpecification,
+				Overrides: []*autoscaling.LaunchTemplateOverrides{
+					{InstanceType: aws.String("c5.2xlarge")},
+					{InstanceType: aws.String("c5n.2xlarge")},
+					{InstanceType: aws.String("c5d.2xlarge")},
+				},
+			},
+		})
+	} else {
+		if launchTemplateSpecification != nil {
+			asg.SetLaunchTemplate(launchTemplateSpecification)
+		}
 	}
 	return asg
 }
@@ -121,6 +134,7 @@ func CreateTestAutoScalingInstance(id, launchConfigurationName string, launchTem
 	instance := &autoscaling.Instance{
 		LifecycleState: aws.String(lifeCycleState),
 		InstanceId:     aws.String(id),
+		InstanceType:   aws.String("c5.2xlarge"),
 	}
 	if len(launchConfigurationName) != 0 {
 		instance.SetLaunchConfigurationName(launchConfigurationName)

main.go

@@ -272,21 +272,23 @@ func SeparateOutdatedFromUpdatedInstances(asg *autoscaling.Group, ec2Svc ec2ifac
 	}
 	targetLaunchConfiguration := asg.LaunchConfigurationName
 	targetLaunchTemplate := asg.LaunchTemplate
+	var targetLaunchTemplateOverrides []*autoscaling.LaunchTemplateOverrides
 	if targetLaunchTemplate == nil && asg.MixedInstancesPolicy != nil && asg.MixedInstancesPolicy.LaunchTemplate != nil {
 		if config.Get().Debug {
 			log.Printf("[%s] using mixed instances policy launch template", aws.StringValue(asg.AutoScalingGroupName))
 		}
 		targetLaunchTemplate = asg.MixedInstancesPolicy.LaunchTemplate.LaunchTemplateSpecification
+		targetLaunchTemplateOverrides = asg.MixedInstancesPolicy.LaunchTemplate.Overrides
 	}
 	if targetLaunchTemplate != nil {
-		return SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplate, asg.Instances, ec2Svc)
+		return SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplate, targetLaunchTemplateOverrides, asg.Instances, ec2Svc)
 	} else if targetLaunchConfiguration != nil {
 		return SeparateOutdatedFromUpdatedInstancesUsingLaunchConfiguration(targetLaunchConfiguration, asg.Instances)
 	}
 	return nil, nil, errors.New("AutoScalingGroup has neither launch template nor launch configuration")
 }
 
-func SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplate *autoscaling.LaunchTemplateSpecification, instances []*autoscaling.Instance, ec2Svc ec2iface.EC2API) ([]*autoscaling.Instance, []*autoscaling.Instance, error) {
+func SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplate *autoscaling.LaunchTemplateSpecification, overrides []*autoscaling.LaunchTemplateOverrides, instances []*autoscaling.Instance, ec2Svc ec2iface.EC2API) ([]*autoscaling.Instance, []*autoscaling.Instance, error) {
 	var (
 		oldInstances   []*autoscaling.Instance
 		newInstances   []*autoscaling.Instance
@@ -319,6 +321,8 @@ func SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplat
 		case aws.StringValue(instance.LaunchTemplate.LaunchTemplateId) != aws.StringValue(targetLaunchTemplate.LaunchTemplateId):
 			fallthrough
 		case !compareLaunchTemplateVersions(targetTemplate, targetLaunchTemplate, instance.LaunchTemplate):
+			fallthrough
+		case overrides != nil && len(overrides) > 0 && !isInstanceTypePartOfLaunchTemplateOverrides(overrides, instance.InstanceType):
 			oldInstances = append(oldInstances, instance)
 		default:
 			newInstances = append(newInstances, instance)
@@ -327,6 +331,15 @@ func SeparateOutdatedFromUpdatedInstancesUsingLaunchTemplate(targetLaunchTemplat
 	return oldInstances, newInstances, nil
 }
 
+func isInstanceTypePartOfLaunchTemplateOverrides(overrides []*autoscaling.LaunchTemplateOverrides, instanceType *string) bool {
+	for _, override := range overrides {
+		if aws.StringValue(override.InstanceType) == aws.StringValue(instanceType) {
+			return true
+		}
+	}
+	return false
+}
+
 func SeparateOutdatedFromUpdatedInstancesUsingLaunchConfiguration(targetLaunchConfigurationName *string, instances []*autoscaling.Instance) ([]*autoscaling.Instance, []*autoscaling.Instance, error) {
 	var (
 		oldInstances []*autoscaling.Instance