Kubernetes MaxVolumeCount少于每个节点的最大Pod

Question

I've just upgraded my Kubernetes cluster to version 1.7.11. This increased the maximum number of pods I can run per node from 40 to 100. However it seems like now I can only attach 39 volumes per node. If I try to create more I get:

No nodes are available that match all of the following predicates:: MaxVolumeCount (3), PodToleratesNodeTaints (1).

This is rather annoying because I was hoping to be able to put more than 40 pods on a node. I don't want to decrease the node size because that would limit the max amount of CPU I can allow a pod to use.

I've setup my cluster on AWS using Kops. Is there a way to change the MaxVolumeCount limit?

Is it normal to have a MaxVolumeCount limit of 39?

System info:

Kernel Version: 4.4.111-k8s
OS Image: Debian GNU/Linux 8 (jessie)
Container Runtime Version: docker://1.12.6
Kubelet Version: v1.7.11
Kube-Proxy Version: v1.7.11
Operating system: linux
Architecture: amd64

Answer 1

Not every pod needs a volume mounted. If you look at ie. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/volume_limits.html there are external factors at work here as the 40 EBS per instance is actually an AWS limitation, not kubernetes one. ALso, not every Volume needs to be backed by EBS, you can have ie. NFS (AWS EFS) which would not fall under the same limit.