Azure Container Instances developer here...
Each container has hypervisor level isolation. We are not relying on kernel level isolation for security isolation between different user's containers.
Each container has hypervisor level isolation. We are not relying on kernel level isolation for security isolation between different user's containers.
The container security model will almost certainly improve in the future, but for now I'm only ok with other people in my same company sharing the kernel, not incentivised attackers.
[edit]
I'm going to unfud my comment. Some further reading makes me think maybe they spin up something like kvm containers and use a minimal distribution such that they can get to "seconds". If it were me, I'd have pre-running instances of the base image that were ready for a customer to attach and own.