Xen is running full virtual machines. You run full operating systems on simulated hardware. The real “host” operating system is the hypervisor (Xen). Inside a VM, you have the concept of one or more CPUs but you do not know which actual CPU cores that maps to. The load can be distributed to any of them by the real host.
In something like Docker, you only run a single host kernel. On top of that you run sandbox environments that run on the kernel that “think” they have an environment to themselves but are actually sharing a single host kernel. The single host kernel directly manages the real hardware. Processes can run on any of the CPUs managed by the single host kernel.
In both of the above, updating the host means shutting the system down.
With this new approach, you have multiple kernels, all running natively on real hardware. Any given CPU is being managed by only one of the kernels. No hypervisor.
I mean isn’t this just Xen revisited? I don’t understand why this is necessary.
Xen is running full virtual machines. You run full operating systems on simulated hardware. The real “host” operating system is the hypervisor (Xen). Inside a VM, you have the concept of one or more CPUs but you do not know which actual CPU cores that maps to. The load can be distributed to any of them by the real host.
In something like Docker, you only run a single host kernel. On top of that you run sandbox environments that run on the kernel that “think” they have an environment to themselves but are actually sharing a single host kernel. The single host kernel directly manages the real hardware. Processes can run on any of the CPUs managed by the single host kernel.
In both of the above, updating the host means shutting the system down.
With this new approach, you have multiple kernels, all running natively on real hardware. Any given CPU is being managed by only one of the kernels. No hypervisor.