Micro VMs are not lower overhead than Docker! Where are people getting this idea that micro VMs are faster? Micro VMs provide greater security isolation, resour

Micro VMs are not lower overhead than Docker! Where are people getting this idea that micro VMs are faster? Micro VMs provide greater security isolation, resource isolation, and allow the guest to run a different kernel/OS than the host, but they aren’t “faster”. OCI runtimes can spawn a container orders of magnitude faster than Firecracker can spawn a VM, even though Firecracker is quite fast and light compared to traditional VM runners. If you’re a hosting provider like Fly or AWS, micro VMs are an important primitive for those reasons. But if you’re a company building out a cluster to run your own apps, you are probably fine to share a Linux kernel version and reign in or relocate noisy neighbors. After all you will probably use the same base Docker container as a starting point for your similar, homogenous apps. If you’re sharing base layers, why not share the kernel at runtime?