upgrade-manager-v2: asg.Instances has duplicate entries.

[shreyas-badiger]

Is this a BUG REPORT or FEATURE REQUEST?:
Bug
What happened:
scalingGroup.Instances contains duplicate entries for the first instance.

 453 func (r *RollingUpgradeReconciler) IsScalingGroupDrifted(rollingUpgrade *v1alpha1.RollingUpgrade) bool {
 454     r.Info("checking if rolling upgrade is completed", "name", rollingUpgrade.NamespacedName())
 455     scalingGroup := awsprovider.SelectScalingGroup(rollingUpgrade.ScalingGroupName(), r.Cloud.ScalingGroups)
 456     for _, instance := range scalingGroup.Instances {
 457         if r.IsInstanceDrifted(rollingUpgrade, instance) {
 458             return true
 459         }
 460     }
 461     return false
 462 }

Line number 456 has duplicate entries.

How to reproduce it (as minimally and precisely as possible):
Just run a regular rolling upgrade and observe the following console logs.

2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	checking if rolling upgrade is completed	{"name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-03cae0d4406f494fc", "name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-03cae0d4406f494fc", "name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-04eea945491938f1b", "name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-0520d1cf7bd430da0", "name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-0ba5f6e688030f196", "name": "kube-system/test-rollup-5"}
2021-04-26T23:27:53.689-0700	INFO	controllers.RollingUpgrade	launch configuration name differs	{"instance": "i-0cf5683650641cddc", "name": "kube-system/test-rollup-5"}

Environment:

• rolling-upgrade-controller version 2
• Kubernetes version : 1.18