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I'm still confused. This is the big thing I'm not really getting:

> which allows you to build both traditional container apps, as well as Wasm apps

I can already do that. Using Rust for the sake of example: `cargo build` can give me a WASM binary, and `docker build` can give me a container. Is Docker+WASM going to replace `cargo build`? Or is it going to wrap the WASM binary produced by cargo in another layer of abstraction? If the latter, how is this new layer of abstraction different from just using one of the WasmEdge docker containers [0]?

I'm not trying to be combative, I'm just sincerely confused at what problem this technical preview is intended to solve.

[0] https://wasmedge.org/book/en/quick_start/use_docker.html

> I'm just sincerely confused at what problem this technical preview is intended to solve.

This is all good feedback, and we’ll definitely try to explain the added value better in the future. The main advantages we see in this technical preview are:

1. Easy, reproducible dev environment to quickly & reliably develop cloud/edge apps that target Wasm, or code frontend apps that target a Wasm backend (for example, as part of a microservice architecture). This is particularly helpful if you build apps that have a mix of Wasm & container components[0]

2. Easy way to share & deploy Wasm artifacts, using trusted infra like Docker Hub, but also Dockerfiles and Docker Compose

3. Transparent, reliable way to deploy Wasm applications to existing container-based infrastructure such as k8s (via OCI images) — but these apps can also be “unpacked” to run natively on edge infrastructure

> is it going to wrap the WASM binary produced by cargo in another layer of abstraction? If the latter, how is this new layer of abstraction different from just using one of the WasmEdge docker containers [0]?

Our approach is close to this. First, it was built with the WasmEdge folks, so you’re correct to detect the similarity. Second, it does wrap resulting artifacts into a OCI image, because we believe that can generate a lot of advantages (points #2 and #3 above) BUT you can also easily unpack the Wasm payload from the binary image at deploytime/runtime if you’d rather deploy your app on Wasm-native infrastructure (as opposed to container-native infra)

Appreciate the feedback. Hope the above helps.

[0]: https://docs.docker.com/desktop/wasm/#running-a-multi-servic...

I think you are falling into a “deeply-technical explainer” trap. You’ve been so deeply engrossed in the use-cases of this novel technical combo that they are all assumed understood from your POV.

And, this tech is so general that there’s a second trap of “What can it do? It can do anything! Sure, but what can it do??” Again, because I’m your head “anything” is pre-supposed to a narrow set of goals that this tech fulfills very nicely. It cannot, for example, take my dog for a walk. So, it can’t do “anything” ;p It’s hard to get out of that head-space because you’ve been so deep in it for so so long.

But, I and 85% of people here have no idea what narrow set of goals Docker+Wasm fulfills. Something about apps and security something something. Mostly for servers probably.

Some awesome-fit exemplar use cases would help a lot.

What's confusing to me is the "main advantages" Tim describes are the same as Docker, so I'm left wondering what's different about it from Docker? The only thing I can parse out of it that's different is 'apps can also be “unpacked” to run natively on edge infrastructure', but I'm not entirely sure what that means.

My best guess is that Tim is trying to say, "now can run your Docker apps on AWS Lambda"?

AWS announced support for containers on Lambda last year[0]

> the "main advantages" [redacted] describes are the same as Docker

Yup, that’s it! If you value Docker to build container apps, we think this will help you build Wasm apps in the same way, and the only container-centric abstraction this Technical Preview uses (packaging artifacts as OCI images) can be bypassed, if you prefer to deploy your artifacts as native Wasm binaries. The latter can be helpful if you are trying to get the full speed & efficiency benefits of a Wasm-native deployment, as the shim in our OCI package introduces a small performance penalty.

[0]: https://aws.amazon.com/blogs/containers/containerizing-lambd...

So the distillation is something like this?

"Docker images can now be deployed directly to the WASM runtime! This means your AWS Lambdas, Cloudflare Workers, etc. will boot faster and cost less..."

When you rehash what Docker already does, it's watering down the messaging. Even adding "AWS announced support for containers on Lambda last year" in the last reply made the voice in my head ask again, "What's different about it? How is it better?"

That’s not quite right. You can’t take an existing container app and just "export" it as Wasm. (Technically you might, but it would require a pretty big re-architecture and re-write, as Wasm doesn’t support garbage collection or multithreading at the moment. It also requires you use a language that can be compiled to Wasm, which can be limiting. Due to this, Wasm — at this stage — is probably best fitted to functions rather than full apps, although that is changing quickly.)

What you can however, is build apps for Wasm (or apps that combine Wasm and containers) with the same ease you currently enjoy when building pure container apps, i.e. see my comment above [0]

[0]: https://news.ycombinator.com/item?id=33324093

I think what's missing is why you'd want to do that.

If I have a rust app on a scratch image, why would I want to turn it into a wasm container?

My assumption is because wasm can run on multiple platforms (x86 and arm) so one image supports both, is that correct? Are there other reasons not as obvious?

Assuming you had code that somehow could either be packaged as a linux container, or as a Wasm binary, then the advantage of the latter would be that yes Wasm supports multiple CPU architectures out of the box, it also consumes less resources (memory, etc.), will usually have faster start times, and the Wasm security sandboxing is stronger.

> it also consumes less resources (memory, etc.)

Really? I would not have expected that. Is that just under the assumption that most apps have an underlying OS (like alpine) and aren't on a scratch container?

I am trying to head around this.

what are the limitations of this? ok, for example can you deploy postgres on the browser with this? can you have a full OS container running on the browser with this, say ubuntu shell frontend with some javascript and an ubuntu container running on the browser?

The first impression from 'Docker + WASM' surely sounds like that is what it is, but after about 30 mins, I am not so sure that is actually the case.

I have some feedback, though more general: can you please stop pushing your flavor of Docker Dev Environments that only works with your proprietary application and get behind the https://containers.dev standard AKA Dev Containers?

You are going to lose this battle because your Dev Environments don't have a lot of buy-in and you're not standardized and open specced. I'd love to see Docker take a more OSS-friendly approach.

So putting it simply, it’s wasmtime with a “wasm-hub”, stapled onto docker?

And I guess dockerfile can serve as a wasm-playlist for stuffing a whole bunch of them in one container? Call it wasm-spotify

So if I understand you correctly, you want Docker to be a trusted host for wasm binaries as well as container images? Where the tooling you've made is intended to aid users along this path.

It sounds like you're anticipating a new market segment for artifact deployment and want to be its primary service provider.

This seems like a good way to muddle the remaining value prop that docker has. I have zero idea why I'd want wasm via docker tooling vs what exists, especially as people more more and more to not-docker for building and running their containers. I think I see what someone is trying to do, but I don't know any dev looking for this or having a problem solved by it.

> I don't know any dev looking for this or having a problem solved by it.

Judging by the reception at KubeCon & elsewhere today, we think at least some folks are excited by it. But it’s still early, and who knows, you may be right in the end. We launched this as a technical preview to test a hypothesis and learn from it, and so far the interactions from this HN thread alone have been greatly helpful.

Why were they excited? What use cases does this address?

Is the intention to containerize WASM binaries and manage them with Docker like you would any other container?

Genuine questions, I'm just trying to understand what this feature is and why someone would want to use it.

I tried to answer this above[0]. Instead of trying to explain it again, I’d encourage you to give it a try[1], and if after going through the 5-minute tutorial you still don’t get the point then a) maybe we messed up (and I’ll be sorry for having wasted your time!) or b) maybe it’s not for you (and I’ll also be sorry I wasted your time). It took me a while to wrap my head around this Docker+Wasm thing too when I first heard about it internally — then again it took me months to wrap my head around my first demo of Docker, so maybe I’m just dense!

[0]: https://news.ycombinator.com/item?id=33324093

[1]: https://docs.docker.com/desktop/wasm/

As a heads up, the download links to the technical preview builds of Docker seem to be incorrect on that page https://docs.docker.com/desktop/wasm/. The Windows, Mac OS Intel and Silicon each point to https://www.docker.com/download/wasm-preview/linuxamd64deb which is the linux build.

The article linked by the OP has the correct links.

Your second link answered my questions well, thanks.

It might be easier if you simplify it to, "We're trying not to be just the app you choose to run containers with. You can now use non-container runtimes like WASM."

So docker+WASM does not build a Linux container image with the WASM application inside but it builds a WASM application packaged as a docker image and started with docker run instead of (say) an ELF or Windows or Mac binary started with the OS exec, whatever it is?

If this is the case I'd leave docker outside the name of the technology. I imagine the confusion. At least one customer of mine doesn't fully get the difference between a docker image and a VM yet, after years they are using docker in production.

> So docker+WASM does not build a Linux container image with the WASM application inside but it builds a WASM application packaged as a docker image

With this preview, we are leveraging the OCI specification that defines how to build an image. Linux/Windows containers are the most common use of this specification, but many other types of artifacts exist (OPA policies, Helm charts, etc.).

When using any of these other artifact types, tooling has to know how to use that specific artifact type and run it (eg, extract the image and run it as a container or extract the Helm chart and deploy it). In our Wasm use case, we are doing the same thing... package and ship a Wasm module and we'll extract it and run it on the new Wasm runtime. That runtime then "converts" the Wasm module into native machine code for the OS you're running on.

> If this is the case I'd leave docker outside the name of the technology. I imagine the confusion.

That's great feedback! While most know us as "the container company", our mission doesn't even talk about containers. We want to help all developers succeed by reducing app complexity. We can certainly do more to help educate folks between the different types of workloads you might be running. We're still very early on in this process, so stay tuned (and keep the feedback coming)!

'Docker + WASM' definitely gave me the impression that docker is now leveraging wasm to be able to run your normal container workloads directly on the browser.

Like if you have any docker container, you can now take that, with some modification and run that directly on the browser. Reading further, I think this is totally not what it actually is.

You could say 'Docker for WASM applications' or 'Docker to deploy WASM apps' that would make the relationship more clear I think.

Now I get it! This should be the tagline, it’s the only thing in the thread that’s made sense to me

Basically yes: if you get value out of Docker for container apps today, we think you’ll get value out of Docker for Wasm apps tomorrow.

Seems promising. I think, based on what I read in this, that most folks don't know how challenging working with WASM is.

That’s our experience as well… This Technical Preview is an early downpayment, and we’re definitely looking for feedback on how one may could make the Wasm development experience better!

It's still not clear to me, so can you bundle source code into your Dockerfile and just have compilation being part of the docker compose step?

Great question! In the demo app we showed yesterday (source here - https://github.com/second-state/microservice-rust-mysql), the Dockerfile is leveraging a multi-stage build where the first stage builds the Wasm module and the second stage extracts the Wasm module into a "FROM scratch" image.

In Compose, the "server" service is running using the image that is produced by that build. It's then handed off to the new Wasm runtime, where the module is extracted and executed. Hope that helps! Feel free to follow up with more questions!

Hi Tim from Docker

How about getting docker running in WASM so I can run containers in the browser?

that's what I thought this was. I was disappointed.

I’ve been able to do this with VS Code Dev containers already. What issue is Docker trying to solve?