PR comments

pkg/cloudprovider/aws/cloudprovider.go

@@ -34,8 +34,13 @@ import (
 )
 
 const (
-	// CacheTTL restricts QPS to AWS APIs to this interval for verifying setup resources.
-	CacheTTL = 5 * time.Minute
+	// CacheTTL restricts QPS to AWS APIs to this interval for verifying setup
+	// resources. This value represents the maximum eventual consistency between
+	// AWS actual state and the controller's ability to provision those
+	// resources. Cache hits enable faster provisioning and reduced API load on
+	// AWS APIs, which can have a serious import on performance and scalability.
+	// DO NOT CHANGE THIS VALUE WITHOUT DUE CONSIDERATION
+	CacheTTL = 60 * time.Second
 	// CacheCleanupInterval triggers cache cleanup (lazy eviction) at this interval.
 	CacheCleanupInterval = 10 * time.Minute
 	// ClusterTagKeyFormat is set on all Kubernetes owned resources.

pkg/cloudprovider/aws/launchtemplate.go

@@ -119,12 +119,18 @@ func (p *LaunchTemplateProvider) Get(ctx context.Context, provisioner *v1alpha1.
 }
 
 func (p *LaunchTemplateProvider) ensureLaunchTemplate(ctx context.Context, options *launchTemplateOptions) (*ec2.LaunchTemplate, error) {
+	var launchTemplate *ec2.LaunchTemplate
 	name := launchTemplateName(options)
+	// 1. Read from cache
+	if launchTemplate, ok := p.cache.Get(name); ok {
+		return launchTemplate.(*ec2.LaunchTemplate), nil
+	}
+	// 2. Attempt to find an existing LT.
 	output, err := p.ec2api.DescribeLaunchTemplatesWithContext(ctx, &ec2.DescribeLaunchTemplatesInput{
 		LaunchTemplateNames: []*string{aws.String(name)},
 	})
-	var launchTemplate *ec2.LaunchTemplate
 	if aerr, ok := err.(awserr.Error); ok && aerr.Code() == "InvalidLaunchTemplateName.NotFoundException" {
+		// 3. Create LT if one doesn't exist
 		launchTemplate, err = p.createLaunchTemplate(ctx, options)
 		if err != nil {
 			return nil, fmt.Errorf("creating launch template, %w", err)
@@ -134,9 +140,10 @@ func (p *LaunchTemplateProvider) ensureLaunchTemplate(ctx context.Context, optio
 	} else if len(output.LaunchTemplates) != 1 {
 		return nil, fmt.Errorf("expected to find one launch template, but found %d", len(output.LaunchTemplates))
 	} else {
-		zap.S().Debugf("Successfully discovered launch template %s", name)
+		zap.S().Debugf("Discovered launch template %s", name)
 		launchTemplate = output.LaunchTemplates[0]
 	}
+	// 4. Populate cache
 	p.cache.Set(name, launchTemplate, CacheTTL)
 	return launchTemplate, nil
 }

pkg/cloudprovider/aws/utils/predicates/tags.go

@@ -17,7 +17,7 @@ func HasNameTag(name string) func([]*ec2.Tag) bool {
 	}
 }
 
-// HasNameTag returns a func that returns true if tag exists with tagKey
+// HasTagKey returns a func that returns true if tag exists with tagKey
 func HasTagKey(tagKey string) func([]*ec2.Tag) bool {
 	return func(tags []*ec2.Tag) bool {
 		for _, tag := range tags {