Support Docker Swarm

[drozzy]

Has anyone used this with docker swarm mode?
Will it work and if yes, could someone provide an example in a stack file?

Thank you very much.

[fatih]

Unfortunately, there are no docker swarm mode examples. Currently, our main focus is to support Kubernetes. I'll update the README.md in the future for other CO's. Thanks!

[drozzy]

A Container Storage Interface (CSI) Driver for DigitalOcean Block Storage. The CSI plugin allows you to use DigitalOcean Block Storage with your preferred Container Orchestrator.

Maybe replace with: "with Kubernetes".

[fatih]

Sure, but this doesn't main that it's not meant to be used with others. If any other CO supports the CSI plugin, somehow is still able to use it. What I mean is that our focus is currently supporting Kubernetes, it doesn't mean the CSI is only meant for Kubernetes. Hope this clarifies it better :) Thanks again for the feedback

[drozzy]

I just wish you supported Docker Swarm Mode (it is way better than old swarm, and much easier to learn than K8s).
Thanks for the explanation.

[olljanat]

FYI. Docker 23.0.0 added CSI support for Swarm mode so unless this plugin uses Kubernetes specific implementation (works as controller, etc) it should be possible to make it working with Docker Swarm now.

I have build some example scripts and guidance to https://github.com/olljanat/csi-plugins-for-docker-swarm which you might find useful.

[timoreimann]

Hi @olljanat,

thanks for the update. The DigitalOcean CSI driver should not come with any Kubernetes-specific implementations (unless we accidentally introduced some, which should be considered a bug). We do use some library functionality from the Kubernetes ecosystem but they should not affect compatibility (e.g., mount helpers).

FWIW, we had a Nomad users trying out the DigitalOcean driver some time ago, which has led to an upstream Nomad ticket being filed to get some CSI spec non-compliance fixed on their end. I haven't heard back from them since then, which makes me assume our driver should generally be usable with container orchestrators other than Kubernetes.

Our main usage is definitely Kubernetes as described earlier in this issue; if anyone spots a problem possibly related to the DigitalOcean driver not behaving in accordance with the spec, however, please do file a new issue on our repo. (End user support pertaining to the configuration or usage of the driver in other orchestrators is definitely out of scope though and should be directed towards the respective orchestrator's community and channels.)

[s4ke]

For anyone considering picking this up: Even though I don't have any digitalocean servers, I think porting the CSI driver to Swarm should be doable. For the Hetzner CSI this meant that we only had to bundle the controller and node binary into a single all in one binary and then create the tooling to build a docker plugin.

You can find the PR over at hetznercloud/csi-driver#376
and a preliminary discussion over at hetznercloud/csi-driver#374

[s4ke]

@timoreimann Docker Swarm plugins have to be packaged specifically for use with Swarm, so it would be great for digitalocean users who want to try this if they can use an official source. Would you accept PRs that add the necessary tooling to build sucha plugin if anyone is interested in working on the CSI support for Swarm?

[timoreimann]

Hey @s4ke, thanks for the offer. Two quick questions:

1. Can you (or anyone else active in this issue right now) confirm that you currently have the need to run the DO CSI driver in Docker Swarm? (Basically trying to confirm here that we have a real use case.)
2. Can you roughly outline the work required to support Docker Swarm with the DO CSI driver? (For what it's worth, the Controller and Node service portions already live in the same binary, though it might not be possible to run them at the same time right now.)

[s4ke]

@timoreimann to be clear. We don't use digitalocean right now so I can't do the work. I can assist with packaging questions as can @olljanat.

[timoreimann]

AFAICS, the last user in this discussion who expressed direct interest in seeing Docker Swarm support was from more than 4 years ago. I'd prefer to see a real world need expressed before committing to any work. At that point though, I'm generally open to external contributions.

[djmaze]

I would be interested as well. Previously I wasn't aware that there could be any chance for CSI compatibility with Swarm so I developed my own minimalistic (non-CSI) plugin in the meantime. But it would very helpful to have a robust and centrally supported CSI alternative. Also, would be willing to test.

[timoreimann]

Thanks @djmaze.

The next step should be to outline the work that needs to be done. This will allow us to ensure it fits with the existing CSI driver structure. Afterwards, any volunteer(s) may drive the work.