Kubernetes: using OpenStack Cinder from one cloud provider while nodes on another

Question

Maybe my question does not make sense, but this is what I'm trying to do:

• I have a running Kubernetes cluster running on CoreOS on bare metal.
• I am trying to mount block storage from an OpenStack cloud provider with Cinder.

From my readings, to be able to connect to the block storage provider, I need kubelet to be configured with cloud-provider=openstack, and use a cloud.conf file for the configuration of credentials.

I did that and the auth part seems to work fine (i.e. I successfully connect to the cloud provider), however kubelet then complains that it cannot find my node on the openstack provider.

I get:

Unable to construct api.Node object for kubelet: failed to get external ID from cloud provider: Failed to find object

This is similar to this question:

Unable to construct api.Node object for kubelet: failed to get external ID from cloud provider: Failed to find object

However, I know kubelet will not find my node at the OpenStack provider since it is not hosted there! The error makes sense, but how do I avoid it?

In short, how do I tell kubelet not to look for my node there, as I only need it to look up the storage block to mount it?

Is it even possible to mount block storage this way? Am I misunderstanding how this works?

Mikael

There is a Kubernetes slack channel where you may want to ask this question as well. – Otes

The slack channel only seems to be for google, redhat, coreos or intel emails. How do i contact the 'team admin' to get an invite? – Mikael

Hmm, I'm not sure. I didn't follow when they moved from irc to slack. I assumed that since they mention it on their page it was public, but I apologize if I sent you on a wild goose chase. – Otes

The slack channel is open to public, but you do have to get the invite and register. – Harwill

i did register for the invite but never got it. now the site says I already got the invite and i need to check for that email i never received. So it's going nowhere. Anyways, I'm more interested in an answer to the question above which I'm stuck with, than with the slack thing. – Mikael

Answer 1

There seem to be new ways to attach Cinder storage to bare metal, but it's apparently just PoC

http://blog.e0ne.info/post/Attach-Cinder-Volume-to-the-Ironic-Instance-without-Nova.aspx

Mikael

Answer 2

Unfortunately, I don't think you can decouple the cloud provider for the node and that for the volume, at least not in the vanilla kubernetes.

Harwill

is there a way to register my own nodes on OpenStack then? – Mikael