[SEJeff]

Thomas, what are your thoughts on micro-vms such as kata containers? You can use them as a backend for docker in place of runc.

I'm sure you're well aware, but for the readers, they are isolated with a CPU's VT instructions which are built to isolate VMS. I still think "containers don't contain" in a very Dan Walsh boston accent, but this seems like a respectable start.

https://katacontainers.io

[tptacek]

I have no strong opinion other than that untrusting cotenants shouldn't directly share a kernel.

[burnt-resistor]

They're slow and so unsuitable for dev work. They might be somewhat better for prod, but it depends on a wide selection of unproven hypervisors.

[tptacek]

Which "unproven" hypervisors are those? Kata works with Firecracker.

[burnt-resistor]

QEMU is more well-known and tested than Firecracker; i.e., a hacked version is used in Xen used everywhere in the past decade while Firecracker is primarily an Amazon-only thing. Cloud Hypervisor, Dragonball, and StratoVirt aren't well-known or battle-tested IMO. The problem is none of these possess true manageability and isolation features of any solid type 1 hypervisor which makes Kata equivalent to a user-space application rather than a reliable platform with harder resource isolation guarantees.

https://github.com/kata-containers/kata-containers/blob/main...

[tptacek]

Firecracker is probably the 2nd or 3rd most widely deployed hypervisor in production deployments. I think "Amazon-only" isn't doing the rhetorical lifting you mean it to do. The idea that it's "equivalent to a user-space application" makes very little sense.

[worthless-trash]

I think they mean in regards to cross kernel attacks. vms didn't protect across speculative execution attacks.

I believe there are even more course grained timing attacks with dma and memory that are waiting to be abused.

[tptacek]

No, that's true, VMs don't protect against microarchitectural attacks. But neither does shared-kernel isolation; in fact, shared-kernel is even worse at it. So if that's the concern, it doesn't make much sense in the threat model.

[burnt-resistor]

Isolation guarantees: Separate metal > type 1 hypervisors > type 2 hypervisors > containers > processes > OS threads > cooperative threads ;)

[worthless-trash]

Accurate and agree.