Add support for IPAM like Whereabouts

[kanlkan]

Problem

DRANET currently does not provide a built-in mechanism for managing IP address ranges for network devices.
As a result, IP address allocation must be implemented separately or reimplemented.

Proposal

Add support for the Whereabouts IPAM project in DRANET.

Whereabouts is primarily designed as a CNI-based IPAM plugin. However, its core IP range management logic can also be reused as a library. By importing it as a library, DRANET could leverage its existing functionality for IP allocation without depending on the CNI plugin interface.

Whereabouts is already widely used in Kubernetes environments and provides a well-tested implementation for managing IP address ranges. Reusing it would avoid reimplementing similar functionality in DRANET and provide a familiar IPAM mechanism for users.

Example

I have prepared a sample implementation demonstrating this approach.
Some demonstration manifests are also included to show how the feature could be used.
https://github.com/kanlkan/dranet/blob/feature/whereabouts-ipam/temp/README.md

Feedback on this approach would be appreciated.
If the direction looks reasonable, I can open a PR with the proposed implementation.

[aojea]

if we need to handle IPAM I prefer to first design the IPAM feature rather than bring this CNI dependencies

[kanlkan]

@aojea
Thank you for your comment.
I agree that the IPAM feature itself should be designed first.

This prototype was mainly intended to explore a minimal implementation path, not to introduce CNI dependencies into DRANET. In the sample, Whereabouts is used only as a library for its core IPAM logic, and the IPAM-related part is kept behind a small API boundary with minimal changes to the existing code.

So I see this as a practical option, rather than the final IPAM design for DRANET. If we later decide to support a richer DRANET-specific IPAM model, the current structure should still allow the backend implementation to be replaced.

[aojea]

We have a lot of ipam libraries, do not worry about that, sketch the feature and make a proposal

[kanlkan]

@aojea
Understood.
The main IPAM requirement I have in mind at this stage is support for managing allocation from explicitly specified IP ranges. If you have a particular IPAM library in mind that fits this requirement well, please point me to it.
I will sketch the feature around that requirement and prepare a sample implementation based on the proposed design.

[aojea]

https://github.com/kubernetes-sigs/kindnet/blob/main/site/content/docs/design/cni/index.md#cni-kindnet

code in https://github.com/kubernetes-sigs/kindnet/blob/8d883e4cd445d13f3ad3e3696e343b61a4d42676/cmd/cni-kindnet/netconf.go#L191

The question is how do we design global state, and is something I've been discussing this week during kubecon with @npinaeva , we may need to design a new component/cluster controller in dranet that handles global state like:

• ipam
• fabric infiniband domains
• fabric vlans ???
• fabric rails?

should be the DeviceClass object the holder of the Global State? I want to avoid having CRDs if possible

[kanlkan]

@aojea
Thank you for pointing this out.

should be the DeviceClass object the holder of the Global State? I want to avoid having CRDs if possible

I do not think DeviceClass should hold the global state.
DeviceClass should mainly be used to specify the DRA driver, filter/select devices, and provide class-level configuration for them. Global state such as IPAM or fabric-wide settings seems like a separate concern.

[tamilmani1989]

can you describe the usecase for this feature? Is this for ipoib interface or any network interface that dra moves inside pod ?

[kanlkan]

@tamilmani1989
My current use case is SR-IOV VFs on RDMA NICs (RoCEv2). However, the IPAM feature itself is not limited to that case and could support any network interfaces that DRA assigns to Pods.

[sathieu]

Cluster-API also has IPAM contract and providers. It's governed by CRDs.

https://cluster-api.sigs.k8s.io/reference/providers.html?highlight=Providers#ip-address-management-ipam

[aojea]

I have a more native proposal, I just need to prototype it, still on vacation this week, will publish the code in a PR for feedback, just please bear with me some time more and keep adding ideas