In practice, this isn't a problem. Any reasonably modern Linux kernel will do. The container image will usually be based on a Linux distribution (so, Ubuntu i

In practice, this isn't a problem. Any reasonably modern Linux kernel will do. The container image will usually be based on a Linux distribution (so, Ubuntu if you want it, often something lightweight like Alpine). Most applications don't actually see the kernel: they see the system library (eg. glibc, musl) and it hides differences in system call versions, etc. This is not a problem in general usage. A container will work on basically any Linux kernel.