Automated cherry pick of #8038: Fix Handling of LaunchTemplate Versions for #8261: Fix RollingUpdate behaviour when using LaunchTemplates for #8567: Treat nil of LaunchTemplateSpecification.Version as $Default

upup/pkg/fi/cloudup/awstasks/autoscalinggroup.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"reflect"
 	"sort"
+	"strconv"
 	"strings"
 
 	"k8s.io/kops/upup/pkg/fi"
@@ -30,6 +31,7 @@ import (
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/autoscaling"
+	"github.com/aws/aws-sdk-go/service/ec2"
 	"k8s.io/klog"
 )
 
@@ -271,6 +273,7 @@ func (v *AutoscalingGroup) RenderAWS(t *awsup.AWSAPITarget, a, e, changes *Autos
 				LaunchTemplateName: e.LaunchTemplate.ID,
 			}
 		}
+
 		// @check if we are using mixed instance policies
 		if e.UseMixedInstancesPolicy() {
 			// we can zero this out for now and use the mixed instance policy for definition
@@ -284,7 +287,7 @@ func (v *AutoscalingGroup) RenderAWS(t *awsup.AWSAPITarget, a, e, changes *Autos
 					SpotMaxPrice:                        e.MixedSpotMaxPrice,
 				},
 				LaunchTemplate: &autoscaling.LaunchTemplate{
-					LaunchTemplateSpecification: &autoscaling.LaunchTemplateSpecification{LaunchTemplateName: e.LaunchTemplate.ID},
+					LaunchTemplateSpecification: &autoscaling.LaunchTemplateSpecification{LaunchTemplateName: e.LaunchTemplate.ID, Version: aws.String("1")},
 				},
 			}
 			p := request.MixedInstancesPolicy.LaunchTemplate
@@ -345,12 +348,26 @@ func (v *AutoscalingGroup) RenderAWS(t *awsup.AWSAPITarget, a, e, changes *Autos
 			return req.MixedInstancesPolicy
 		}
 
+		launchTemplateVersion := "1"
+		if e.LaunchTemplate != nil {
+			dltRequest := &ec2.DescribeLaunchTemplatesInput{
+				LaunchTemplateNames: []*string{e.LaunchTemplate.ID},
+			}
+			dltResponse, err := t.Cloud.EC2().DescribeLaunchTemplates(dltRequest)
+			if err != nil {
+				klog.Warningf("could not find existing LaunchTemplate: %v", err)
+			} else {
+				launchTemplateVersion = strconv.FormatInt(*dltResponse.LaunchTemplates[0].LatestVersionNumber, 10)
+			}
+		}
+
 		if changes.LaunchTemplate != nil {
 			// @note: at the moment we are only using launch templates when using mixed instance policies,
 			// but this might change
 			setup(request).LaunchTemplate = &autoscaling.LaunchTemplate{
 				LaunchTemplateSpecification: &autoscaling.LaunchTemplateSpecification{
 					LaunchTemplateName: changes.LaunchTemplate.ID,
+					Version:            &launchTemplateVersion,
 				},
 			}
 			changes.LaunchTemplate = nil
@@ -381,6 +398,7 @@ func (v *AutoscalingGroup) RenderAWS(t *awsup.AWSAPITarget, a, e, changes *Autos
 				setup(request).LaunchTemplate = &autoscaling.LaunchTemplate{
 					LaunchTemplateSpecification: &autoscaling.LaunchTemplateSpecification{
 						LaunchTemplateName: e.LaunchTemplate.ID,
+						Version:            &launchTemplateVersion,
 					},
 				}
 			}

upup/pkg/fi/cloudup/awsup/aws_cloud.go

@@ -591,25 +591,30 @@ func findAutoscalingGroupLaunchConfiguration(c AWSCloud, g *autoscaling.Group) (
 	if g.MixedInstancesPolicy != nil {
 		if g.MixedInstancesPolicy.LaunchTemplate != nil {
 			if g.MixedInstancesPolicy.LaunchTemplate.LaunchTemplateSpecification != nil {
-				// honestly!!
-				name = aws.StringValue(g.MixedInstancesPolicy.LaunchTemplate.LaunchTemplateSpecification.LaunchTemplateName)
-				request := &ec2.DescribeLaunchTemplateVersionsInput{
-					LaunchTemplateName: &name,
-				}
-
-				versions, err := c.EC2().DescribeLaunchTemplateVersions(request)
-				if err != nil {
-					return "", fmt.Errorf("error finding versions for launch template: %v", err)
-				}
-
 				var version string
-				for _, v := range versions.LaunchTemplateVersions {
-					if *v.DefaultVersion {
-						version = strconv.FormatInt(*v.VersionNumber, 10)
-						break
+				name = aws.StringValue(g.MixedInstancesPolicy.LaunchTemplate.LaunchTemplateSpecification.LaunchTemplateName)
+				//See what version the ASG is set to use
+				mixedVersion := aws.StringValue(g.MixedInstancesPolicy.LaunchTemplate.LaunchTemplateSpecification.Version)
+				//Correctly Handle Default and Latest Versions
+				if mixedVersion == "" || mixedVersion == "$Default" || mixedVersion == "$Latest" {
+					request := &ec2.DescribeLaunchTemplatesInput{
+						LaunchTemplateNames: []*string{&name},
+					}
+					dltResponse, err := c.EC2().DescribeLaunchTemplates(request)
+					if err != nil {
+						return "", fmt.Errorf("error describing launch templates: %v", err)
 					}
+					launchTemplate := dltResponse.LaunchTemplates[0]
+					if mixedVersion == "" || mixedVersion == "$Default" {
+						version = strconv.FormatInt(*launchTemplate.DefaultVersionNumber, 10)
+					} else {
+						version = strconv.FormatInt(*launchTemplate.LatestVersionNumber, 10)
+					}
+				} else {
+					version = mixedVersion
 				}
-
+				klog.V(4).Infof("Launch Template Version Specified By ASG: %v", mixedVersion)
+				klog.V(4).Infof("Launch Template Version we are using for compare: %v", version)
 				if name != "" {
 					launchTemplate := name + ":" + version
 					return launchTemplate, nil