containerd-wasm-shims VS runc

Besides deploying the application locally and deploying to Fermyon Cloud, you can also deploy your Spin application to Kubernetes using the new Containerd integration for Spin.

Yeah, runtimeClass lets you specify which CRI plugin you want based on what you have available. Here's an example from the containerd documentation - you could have one node that can run containers under standard runc, gvisor, kata containers, or WASM. Without runtimeClass, you'd need either some form of custom solution or four differently configured nodes to run those different runtimes. That's how krustlet did it - you'd have kubelet/containerd nodes and krustlet/wasm nodes, and could only run the appropriate workload on each node type.

You can absolutely install the wasm shim without Desktop. (They won't tell you that because Desktop is a revenue stream for Mirantis.)

In your VM or WSL instance that's running Docker, get the shim from here: https://github.com/deislabs/containerd-wasm-shims (You might need to build it yourself)

Then specify the --runtime and --platform arguments like instructed in the doc, but with a slight modification:

--runtime=containerd-wasm-shim=/path/to/containerd/wasm/shim

This works because the container runtime is simply a Go binary, and Go binaries are completely self-contained.

I can speak to this. Containers, and by extension k8s, break a well known security boundary that has existed for a very long time - whether you are using a real (hardware) server or a virtual machine on the cloud if you pop that instance/server generally speaking you only have access to that server. Yeh, you might find a db config with connection details if you landed on say a web app host but in general you still have to work to start popping the next N servers.

That's not the case when you are running in k8s and the last container breakout was just announced ~1 month ago: https://github.com/opencontainers/runc/security/advisories/G... .

At the end of the day it is simply not a security boundary. It can solve other problems but not security ones.

It's interesting that, in light of things like this, you still see large software companies adding support for new components written in non-memory safe languages (e.g. C)

As an example Red Hat OpenShift added support for crun(https://github.com/containers/crun) this year(https://cloud.redhat.com/blog/whats-new-in-red-hat-openshift...), which is written in C as an alternative to runc, which is written in Go(https://github.com/opencontainers/runc)...

Rabbit hole indeed. That wasn't related to my job at the time, lol. The job change came with a company-provided computer and that put an end to the tinkering.

BTW, I found my hacks to make runc run on Chromebook: https://github.com/opencontainers/runc/compare/main...gabrys...

being the main author of crun, I can clarify that statement: I am not a fan of Go _for this particular use case_.

Using C instead of Go avoided a bunch of the workarounds that exists in runc to workaround the Go runtime, e.g. https://github.com/opencontainers/runc/blob/main/libcontaine...

runc

Not OP, but if I had to guess, a lot of this can be picked up by just observing common security issues in the Linux space, since similar mistakes and oversights have caused quite a few real-world CVEs in the past, e.g. this random example of a TOCTTOU vulnerability in runc.