> Fly.io takes Docker containers and converts them into fleets of Firecracker micro-vms running in racks around the world. If you have a working Docker containe

> Fly.io takes Docker containers and converts them into fleets of Firecracker micro-vms running in racks around the world. If you have a working Docker container, you can run it close to your users, whether they're in Singapore or Amsterdam, with just a couple of commands. FWIW these are OCI images, which can be built with other tools besides Docker. These are not the same thing as containers. I think Docker is overrated and am glad to be using a Containerfile instead of a Dockerfile (it's the same format). Firecracker is great but there is an alternative: https://katacontainers.io/ https://katacontainers.io/ There seems to be confusion as to what Firecracker is doing. Docker in Docker isn't really Docker in Docker when it's in a MicroVM - except for being run by an OCI image. https://community.fly.io/t/fly-containers-as-a-ci-runners/1072 https://community.fly.io/t/fly-containers-as-a-ci-runners/10... Docker uses LXC containers, and an LXC container inside an LXC container is likely to have performance problems. MicroVMs, on the other hand, are similar to VPSes. fly.io suggests that "CPU cores, for instance, should only ever be doing work for one microVM". https://fly.io/docs/reference/architecture/ https://fly.io/docs/reference/architecture/ These MicroVM's are not cheap, and maybe it would be nice to be able to share a VCPU between multiple containers in a lot of situations. Fly.io could be burning a lot of investor money. I think WASM and Deno are good ways to break down a MicroVM with a whole VCPU into smaller sandboxed entities. Also Docker run by an OCI image makes more sense in a MicroVM that has a whole CPU than it does in an LXC container with less than a whole CPU. I do think fly.io is pretty cool. I hope they find ways to educate people more about the difference between a MicroVM (not invented by AWS) and a LXC container and to get people making more use of their heavier weight "containers". Edit: I noticed that in their free tier and low cost plan, they have shared CPUs. https://fly.io/docs/about/pricing/ https://fly.io/docs/about/pricing/ They are charging quite a bit more for one dedicated CPU than DigitalOcean, Vultr, and Lightsail. The cheapest one is $31.00/mo. It's quite similar to Google Could Run. It looks like Cloud Run doesn't have an option to run less than a vCPU in memory though. That means you can pay fly.io $6/mo for a MicroVM with a gig of memory and not have a full cold start, but have a shared CPU which will of course cause latency but probably typically less than a cold start, but you can't pay Google $6/mo and get that. https://cloud.google.com/run/pricing https://cloud.google.com/run/pricing Also websockets can stay open with a shared CPU, but can't in between the VM stopping and starting. I don't know if the $6/mo 1GB MicroVM with a shared vCPU is sustainable, but if so, it's a pretty impressive way to host an app that uses websockets for super cheap. Edit 2: I said "They are charging quite a bit more for one dedicated CPU than DigitalOcean, Vultr, and Lightsail." - I was actually wrong here. It is more for self-hosting if you would run a database like PostgreSQL/MySQL in a VPS (they don't discourage it, and it's pretty simple to do) but wouldn't run a database like PostgreSQL/MySQL in a Fly.io VM (they might discourage it, and it's a bit tricky to do).