Kubelet disregards "hostname-override" if cloud-provider=aws is set

[trondhindenes]

/kind bug

What happened:
Given a kubelet configured with --cloud-provider=aws, --hostname-override=ldm-0110069 and --register-node=true, the kubelet still tries to register with the api server as the "aws-specified" hostname (for example ip-something.eu-west-1.compute.internal). This is problematic for custom provisioners if the configured node cert doesn't include the "aws-format" node name, as kube-apiserver won't allow the node to register. In general there's very little information in the docs about what the "cloud-provider" flag actually does, but IMHO it's pretty clear that the "hostname-override" flag should "win" (especially since that flag is explicitly documented while the cloud-provider flag isnt).

What you expected to happen:
Kubelet should register with the configured value of --hostname-override.

How to reproduce it (as minimally and precisely as possible):
Configure a kubelet on an aws instance with the flags listed above. In order to verify that this indeed caused by the cloud-provider flag, remove that flag from the kublet parameter and restart the kubelet service/pod. The kubelet is now able to register to the api with the name specified in hostname-override

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version): 1.10.2
• Cloud provider or hardware configuration: aws
• OS (e.g. from /etc/os-release): ubuntu 16.04
• Kernel (e.g. uname -a):
• Install tools: custom
• Others:

[trondhindenes]

/sig aws

[liggitt]

/close

duplicate of #54482

when using --cloud-provider, the cloud provider is authoritative on the node name and addresses

that cannot be overridden via a kubelet flag, or the other components (apiserver, controller manager, etc) would have no trustworthy way of know what node name corresponded to a particular AWS instance.

See work in progress to allow labeling AWS instances with the desired node name in #61878

[trondhindenes]

Thanks. I still think the cloud-provider flag could have been documented better, it's next to impossible to figure out what it actually does (and doesn't). Thanks for replying anyway.

[liggitt]

I still think the cloud-provider flag could have been documented better, it's next to impossible to figure out what it actually does (and doesn't).

That's fair. Opened #64661 and kubernetes/website#8873 as a start