amazon-web-services - cluster-autoscaler无法扩展kubernetes集群

Question

我在k8s上通过kops创建了aws集群，节点自动缩放组配置如下:

metadata:
creationTimestamp: "2017-03-21T03:53:26Z"
name: nodes
spec:
  associatePublicIp: true
  image: kope.io/k8s-1.4-debian-jessie-amd64-hvm-ebs-2016-10-21
  machineType: t2.medium
  maxSize: 5
  minSize: 2
  role: Node
  zones:
  - us-west-1a
  - us-west-1c

aws控制台显示当前asg，例如:

desired:2; min:2; max:5

然后我使用 official doc安装 add-ons --- cluster-autoscaler，然后部署一个Pod，当前集群无法提供资源，但是 cluster-autoscaler不会将节点添加到集群，日志如下所示:

admin@ip-10-0-52-252:/var/log$kubectl logs -f cluster-autoscaler-1581749901-fqbzk -n kube-system
I0322 07:08:43.407683       1 event.go:216] Event(api.ObjectReference{Kind:"Pod", Namespace:"default", Name:"new-mq-test-951523717-trd2s", UID:"9437ac54-0ecd-11e7-8779-0257a5d4c012", APIVersion:"v1", ResourceVersion:"189546", FieldPath:""}): type: 'Normal' reason: 'NotTriggerScaleUp' pod didn't trigger scale-up (it wouldn't fit if a new node is added)
I0322 07:08:43.407910       1 event.go:216] Event(api.ObjectReference{Kind:"Pod", Namespace:"default", Name:"new-mq-test-951523717-n986l", UID:"9437a3db-0ecd-11e7-8779-0257a5d4c012", APIVersion:"v1", ResourceVersion:"189543", FieldPath:""}): type: 'Normal' reason: 'NotTriggerScaleUp' pod didn't trigger scale-up (it wouldn't fit if a new node is added)

那么，为什么 cluster-autoscaler无法通过添加ec2节点来扩展集群呢？任何答案都非常感谢

Answer 1

最终我找到了答案，我的默认kops asg的nodes配置是t2.medium，而我部署了需要5000M进行存储的Pod，因为我们所有的kont t2.medium内存都是4GB，它不能满足要求，所以cluster-autoscaler不能放大!