kuasar VS gvisor

Right now most early examples alas boot a container with a wasm runtime for each wasm instance, which is a sad waste. The whole advantage of wasm should be very lightweight low overhead wasm runtime instances atop a common wasm process. Having a process or container for each instance loses a ton of the benefit, makes it not much better than a regular container.

Thankfully there is work like the Containerd Sandbox API which enables new architectures like this. https://github.com/containerd/containerd/issues/4131

It's still being used to spawn a wasm processes per instance for now, but container runtime project Kuasar is already using the Sandbox API to save significant resources, and has already chimed in in comments on HN to express a desire to have shared-process/multi-wasm-instamxe runtimes, which could indeed allow sub ms spawning that could enable instance per request architectures. https://github.com/kuasar-io/kuasar

To be pedantic for a moment...

> You can't use Go to write a kernel ...

Not a production kernel, but MIT did use Go to "study the performance trade-offs of using a high-level language with garbage collection to implement a kernel" [1]

There is also gVisor [2] which implements, as best as I can describe, a kernel in user space. It's intent is to intercept syscalls made in containers and to redirect its execution in a sandbox.

> ... program a microcontroller ...

I'm not sure if one would classify this as a microcontroller, but USB Armory did write a, iirc, Go compliant runtime for bare metal ARM and RISC-V [3]

[1] https://github.com/mit-pdos/biscuit

[2] https://gvisor.dev/

[3] https://github.com/usbarmory/tamago

Although the documentation also mentions "youki", that is mentioned as a "drop-in replacement" of the default runtime basically doing the same, so let's stick with runc. The second runtime will be Kata runtime from Kata containers, since it runs small virtual machines which is good for showing how differently it uses the CPU and memory. This also adds a higher level of isolation with some downsides as well. And the third runtime will be runsc from gVisor which is a perfect third runtime to see how we can run containers and still have a little more secure isolation. I will show how we can recognize the differences by running commands from the isolated environments and from the host.

I find the README of the repo much better to quickly understand what this software is and isn't.

https://github.com/google/gvisor

If you think about it virtualization is just a narrowing of the application-kernel interface. In a standard setting the application has a wide kernel interface available to it with dozens (ex. seccomp) to 100's of syscalls. A vulnerablility in any one of which could result in complete system compromise.

With virtualization the attack surface is narrowed to pretty much just the virtualization interface.

The problem with current virtualization (or more specifically, the VMM's) is that it can be cumbersome, for example memory management is a serious annoyance. The kernel is built to hog memory for cache and etc. but you don't want the guest to be doing that - since you want to overcommit memory as guests will rarely use 100% of what is given to them (especially when the guest is just a jailed singular application), workarounds such as free page reporting and drop_caches hacks exist.

I would expect eventually to see high performance custom kernels for a application jails - for example: gVisor[1] acts as a syscall interceptor (and can use KVM too!) and a custom kernel. Or a modified linux kernel with patched pain points for the guest.

[1] <https://gvisor.dev/>

Hillai: Following our research, Alibaba took several steps to address the vulnerabilities we discovered. They limited image pull secret permissions to read-only access, preventing unauthorized uploads. Additionally, they implemented a secure container technology similar to Google's gVisor project. This technology hardens containers and makes them more difficult to escape from, adding another layer of security.

If you want to use netstack without Bazel, just use the go branch:

https://github.com/google/gvisor/tree/go

go get gvisor.dev/gvisor/pkg/tcpip@go

The go branch is auto generated with all of the generated code checked in.

Isn't gVisor kind of this as well?

"gVisor is an application kernel for containers. It limits the host kernel surface accessible to the application while still giving the application access to all the features it expects. Unlike most kernels, gVisor does not assume or require a fixed set of physical resources; instead, it leverages existing host kernel functionality and runs as a normal process. In other words, gVisor implements Linux by way of Linux."

https://github.com/google/gvisor