Topic
Using Firecracker-style microVMs with their own kernels as a middle ground between shared-kernel containers and full VMs.
Netlify moved Edge Functions off hosted V8 isolates onto Firecracker MicroVMs in its own network, cutting warm overhead from 25-40 ms to a 5-6 ms median. A dev.to analysis argues that for other edge teams, removing an external network hop can matter as much as a faster runtime.
Reality
Microsoft made Azure Container Apps Express generally available on a sandbox layer that starts isolated microVMs from prewarmed pools in under a second. The agent-oriented engineering sits in that layer, while Express on top keeps a narrow slice of Container Apps features.
Reality
Docker Cloud Sandboxes let one command move a coding agent's microVM sandbox from laptop to cloud, for runs Docker pitches at up to 21 hours. Where an agent runs becomes a CLI choice, though commenters argue the harder limit is which outside services it can reach.
Reality
Docker's new Cloud Sandboxes run AI agents unattended for hours in microVMs on Docker-hosted compute that scales from 1 to 16 vCPUs. Teams that adopt it move agent secrets and policy enforcement into Docker's cloud, on isolation claims that so far come only from Docker.
Reality
Amazon patched a symlink-following chown in Firecracker's jailer that only affected aarch64. Behind it sits a seccomp policy that permits io_uring, and researcher antitree shows how that hands back file-system calls the filter denies.
Reality
The V2 runtime allocates session memory on demand and hands it back mid-run, and it restores each new instance from a snapshot of an already prepared environment. AWS measured P75 cold starts of 1.9 to 2.0 seconds on images from 200 MB to 2 GB.
Reality
Firecracker's sub-200ms boot is real, but it only counts on a host you are already paying for by the hour, which is why an experimental GitHub Actions runner project stands or falls on its author's scheduler.
Reality
Encore's crackling drives Firecracker on Linux and Apple's hypervisor on macOS. Getting one set of images to boot on both meant re-implementing much of what Docker and a Linux host do for free.
Reality
A developer who once preached managed databases now runs Postgres on a Firecracker microVM. The interesting part is not the price gap, it is which job moves back onto your desk.
Reality