> Back in the day, people insisted that containers were not security boundaries and should not be treated as such. They're meant to contain things from going off the rails unintentionally, but an actual threat was another story.
> However, realistically, given the env that a container gives you, it certainly looks and feels like a security boundary.
It has to be secure. Browsers are using pretty much the same technologies (seccomp-bpf, cgroups, namespaces, etc) to tightly sandbox Javascript from websites. Browsers run wildly untrusted code from all over the web, and are expected to pass through many forms of malware, not letting them escape the sandbox.
If containers can't be made secure, we have bigger problems.
> So are we just going to be stuck in this retroactive security cleanup mode forever? My point is that if it were designed from the ground up with the hard security boundary in mind, would we have ended up with containers in the first place?
No! Linux and Unix APIs are a mess of patchworks. They are pretty much insecure by default, with rare exceptions.
We could make a new platform with a saner API and make it run on top of Linux, and write new backend services targeting it. I think WASI may just be that. The only problem is that wasm have some overhead / doesn't have access to all CPU features.