4 ms·

What exactly is involved in converting them to root filesystems?

iampims 6y ago
I’d love to know more about this as well. That’s the part usually nobody talks about.
e12e 6y ago
Have a look at: https://stackoverflow.com/questions/23436613/how-can-i-convert-a-docker-image-into-a-vagrant-virtualbox-box#42845276 https://stackoverflow.com/questions/23436613/how-can-i-conve... Or "slim": https://news.ycombinator.com/item?id=20182141 https://news.ycombinator.com/item?id=20182141 Typically, a docker filesystem doesn't include a proper unit (docker will inject "tiny init") - so you would probably have to add a kernel, and init, somehow. I think I'd prefer to just create a vm, rather than re-use the pre-built docker.
- e12e 6y ago
  Ed: a proper "init" not "unit"
CodesInChaos 6y ago
The linked article contains a script building the file system. It creates a block device using `qemu-img`, adds an empty filesystem using `mkfs.ext4` and then simply mounts it and copies in the files. The previous posts cover this topic in more detail: Day 43: Building VM images - https://jvns.ca/blog/2021/01/21/day-43--building-vm-images/ https://jvns.ca/blog/2021/01/21/day-43--building-vm-images/ Day 44: Building my VMs with Docker - https://jvns.ca/blog/2021/01/22/day-44--got-some-vms-to-start-in-firecracker/ https://jvns.ca/blog/2021/01/22/day-44--got-some-vms-to-star...
nicwolff 6y ago
It may not be what fly.io does but there's a walkthrough of the basic idea here https://iximiuz.com/en/posts/from-docker-container-to-bootable-linux-disk-image/ https://iximiuz.com/en/posts/from-docker-container-to-bootab...
tptacek 6y ago
It's not a big secret or anything but it's changed recently and Jerome would do a better job of describing it than I would; apart from the filesystem stuff, we have an init we wrote in Rust that does a bunch of the lifting.
jeromegn 6y ago
We use containerd with the devmapper snapshotter! Works nicely. We create a hard link to the resulting device for the root drive inside firecracker.

I’d love to know more about this as well. That’s the part usually nobody talks about.

e12e 6y ago

Have a look at: https://stackoverflow.com/questions/23436613/how-can-i-convert-a-docker-image-into-a-vagrant-virtualbox-box#42845276 https://stackoverflow.com/questions/23436613/how-can-i-conve... Or "slim": https://news.ycombinator.com/item?id=20182141 https://news.ycombinator.com/item?id=20182141 Typically, a docker filesystem doesn't include a proper unit (docker will inject "tiny init") - so you would probably have to add a kernel, and init, somehow. I think I'd prefer to just create a vm, rather than re-use the pre-built docker.

e12e 6y ago
Ed: a proper "init" not "unit"

CodesInChaos 6y ago

The linked article contains a script building the file system. It creates a block device using `qemu-img`, adds an empty filesystem using `mkfs.ext4` and then simply mounts it and copies in the files. The previous posts cover this topic in more detail: Day 43: Building VM images - https://jvns.ca/blog/2021/01/21/day-43--building-vm-images/ https://jvns.ca/blog/2021/01/21/day-43--building-vm-images/ Day 44: Building my VMs with Docker - https://jvns.ca/blog/2021/01/22/day-44--got-some-vms-to-start-in-firecracker/ https://jvns.ca/blog/2021/01/22/day-44--got-some-vms-to-star...

nicwolff 6y ago

It may not be what fly.io does but there's a walkthrough of the basic idea here https://iximiuz.com/en/posts/from-docker-container-to-bootable-linux-disk-image/ https://iximiuz.com/en/posts/from-docker-container-to-bootab...

tptacek 6y ago

It's not a big secret or anything but it's changed recently and Jerome would do a better job of describing it than I would; apart from the filesystem stuff, we have an init we wrote in Rust that does a bunch of the lifting.

jeromegn 6y ago

We use containerd with the devmapper snapshotter! Works nicely. We create a hard link to the resulting device for the root drive inside firecracker.