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55 points by _ananos_ 11 hours ago | 12 comments

Lliora 6 hours ago

Ran gVisor on a Pi 4 cluster for home IoT sandboxing. Memory overhead is real—about 120MB per sandbox vs 15MB for raw containers. On 4GB boards that limits you to ~25 isolated services before OOM kicks in. Also, syscall拦截 adds 30-40% CPU overhead on ARM. Works fine for untrusted Python scripts, but I wouldn’t run anything compute-heavy.

eptcyka 3 hours ago

Wouldn’t compute workloads be fine as they should not be syscall bound?

_ananos_ 2 hours ago

yeap -- compute would be nearly the same. I suspect you need some kind of I/O to make your compute useful (get input for the computation / produce output etc.) so, still, this would have a negative effect overall.

geerlingguy 8 hours ago

> Fair warning: compiling a kernel on the Pi itself takes several hours.

One nit: this should only take about 40 minutes on a Pi 5, assuming you're compiling with -j6 to use all the cores.

(Still faster to cross-compile)

pelcg 6 hours ago

That is kind of what I was thinking too, and cross-compilation is still the fastest way to build for a different target.

bionade24 8 hours ago

Using distcc networked compilation instead of cross-compiling is reasonably fast too and easier to set up if one isn't familiar with either.

uber1024 7 hours ago

the most frustrating part with having to compile a custom kernel is the maintenance burden (packaging/updating etc.), and not the time it takes to build…

I had a similar issue with networking modules for calico (k8s cni) on both rpis and jetson boards…

_ananos_ 8 hours ago

well, the tricky detail here (which we do not mention in the post, our bad) is that we got the raspbian config (cp /boot/config ... .config && make oldconfig) which includes most modules, and that's why it took more.

But yeap, good point about using the -j flag, it really accelerates the build!

pelcg 6 hours ago

What use-cases are there for gVisor on Raspbian, given that the target is a Raspberry Pi?

_ananos_ 6 hours ago

the simplest one (and the one we're targetting) is multi-tenant services. You want to sandbox your service so that it doesn't affect the rest of the services running.

<shameless plug> We're building a container runtime to do this, and we are comparing alternatives, that's how we got there: https://github.com/urunc-dev/urunc</shameless plug>

bitwize 2 hours ago

gVisor's architecture is fascinating. Years ago I wrote an essay that was kind of a response to all the cracks about "systemd-kerneld" that have been made over the years. Written in character as "Fake Lennart Poettering", it proposed a strategy, using techniques inspired by NetBSD's rump kernel libraries, to turn systemd into a kernel, which would then load a Linux image and "pass through" all system calls to it except those systemd wanted to intercept. Which is kinda the opposite of what gVisor does!

Some guy on a German Linux forum thought my idea was an actual plan by the systemd team, and another poster had to correct him that the author was "FAKE Lennart Poettering", so the joke either didn't land or landed all too well, depending on your perspective...

_ananos_ 25 minutes ago

well, jokes aside, what you're describing, is kind of what a "secure" (with many air/literal quotes) MCP/Agentic architecture looks like :D

In this context we're experimenting with gvisor on various platforms, and we're preparing a demo for kubecon about a fine-grained sandboxing approach for AI agent tasks spawned from a sandboxed agent.