cluster-autoscaler无法扩展kubernetes集群

Question

I create a k8s cluster by kops on aws , the node auto scaling group configuration like:

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

the aws console shows current asg like:

desired:2; min:2; max:5

then I install the add-ons --- cluster-autoscaler by using the official doc , then I deploy a pod which current cluster can't supply the resource, but cluster-autoscaler doesn't add the node to the cluster, logs is like below:

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)

so why the cluster-autoscaler doesn't scale up the cluster by adding the ec2 nodes ? any answers are very appreciated

Answer 1

最终我找到了答案，我的默认nodes asg kops配置是t2.medium ，而我部署的Pod需要5000M的内存，因为我们都知道t2.medium内存是4GB ，无法满足要求，所以cluster-autoscaler无法扩展！

Answer 2

I faced a similar issue while trying to use Kubernetes autoscaling on Google Container Engine. This normally happens when your cluster doesn't contain enough nodes to accomodate anymore Kubernetes pod .

The solution to this is to enable autoscaling in your cluster (AWS EC2 in your case) along with kubernetes autoscaling.

Checkout the following Kubernetes documentation for autoscaling on AWS for further information: link .