init-snapshot VS image-spec

Compare init-snapshot vs image-spec and see what are their differences.

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init-snapshot image-spec
5 24
240 3,125
0.0% 1.0%
0.0 7.8
almost 3 years ago 10 days ago
Rust Go
MIT License Apache License 2.0
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.


Posts with mentions or reviews of init-snapshot. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-02-27.
  • Firecracker internals: deep dive inside the technology powering AWS Lambda(2021)
    9 projects | | 27 Feb 2023
    At CodeSandbox we use Firecracker to run our VMs (more info here:

    To answer the questions:

    > what version of the kernel do you use (the github page says 5.10 but isn't that quite old?)

    Right, they have tested with 5.10, but it also works with higher kernel versions. Our host currently runs 5.19 and we're planning to upgrade to 6.1 soon. The guest runs 5.15.63, we use a config very similar to the recommended config by FC team (it's in the FC repo). It's important to mention that we had to disable async pagefaulting (a KVM feature) with more modern kernel versions, as VMs could get stuck waiting for an PF resolve.

    > What do you use to build the 'micro' images

    We created a CLI that creates a rootfs from a Docker image. It pulls the image, creates a container and then extracts the fs from it to an ext4 disk. For the init, we forked the open sourced init from the Fly team ( and changed/added some functionality.

    > How do you keep timesync of you're not using a timesync daemon?

    IIRC we expose the time as a PTP device (handled by kvm) and run phc2sys to sync the time in an interval. Firecracker has some documentation on this, where it recommends chrony. It can also be done with vsock, but it would be more manual.

    > Handle kernel and app logs without adding an log daemon, and same through vsocks, etc?

    The init forwards stdout/stderr of the command it runs to its own stdout, which Firecracker then logs out by itself. A supervisor reads these and writes the logs to files.

  • The Reclaimer of Heroku's Magic
    5 projects | | 15 May 2022
    Unless they’ve changed things, there is no containerization within the VM a la kata. They run their own custom init inside the VM and use it to start the entry point. is the source.
  • Docker without Docker
    5 projects | | 2 Jun 2021
    Jerome wrote our init in Rust, and, after being cajoled by Josh Triplett, [we released the code (, which you can go read.


Posts with mentions or reviews of image-spec. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2024-01-08.
  • Dive: A tool for exploring a Docker image, layer contents and more
    4 projects | | 8 Jan 2024
    Eventually, once zstd support gets fully supported, and tiny gzip compression windows are not a limitation, then compressing a full layer would almost certainly have a better ratio over several smaller layers

  • Containers - entre historia y runtimes
    3 projects | | 26 Apr 2023
  • Pushing container images to GitHub Container Registry with GitHub Actions
    3 projects | | 1 Dec 2022
    GitHub Container Registry stores container images within your organization or personal account, and allows you to associate an image with a repository. It currently supports both the Docker Image Manifest V2, Schema 2 and Open Container Initiative (OCI) specifications.
  • The cloud-agnostic-architecture illusion
    5 projects | | 19 Aug 2022
    We build all services as containerized workloads, i.e., OCI images - sometimes called Docker images. We deploy these to the Kubernetes product offered by the cloud vendor. Whenever we need some capability, containers are the answer. This insulates our applications from the vendor. In principle, we could switch providers as long as Kubernetes is available.
  • Containerd... Do I use Docker to build the container image? I miss the Docker Shim
    5 projects | /r/kubernetes | 25 Jun 2022
    Build images with anything that makes OCI compliant images, push, and profit.
  • Opensource Server Hosting/Management Web Panel
    3 projects | /r/admincraft | 22 Jun 2022
    it's funny that you mention this because it is actually the thing that is next on my agenda for the image, as you can probably see already I bake in OCI image annotations in our image, which is great for including some core pieces of meta data. In addition to this though I will soon be including custom labels for Base64 encoded YAMLs for Kubernetes deployments using this image. I will look at including helm configuration as well. Then it should be just as easy as: $ docker pull $ docker image inspect | jq -r ".[].Config.Labels.\"org.arcadiatech.crafty.k8s.deployment\"" | base64 -d | kubectl apply -f -
  • My director is mad that I accepted another internal position for a 26% raise when he was told he could only give me a 10%
    6 projects | /r/antiwork | 15 May 2022
    They still don't do anything really of substance, they're just gateways to their vendor's world - booking systems, payment systems, etc. You learn those as you go along. Yes, as a potential employee, you need to be able to tick those boxes on your CV, but if you understand the underlying technology, it's mostly a matter of booking your own AWS or Azure server for $5-10 a month for a few weeks, and fooling around. (Docker is a bit different in the sense that they were the first to popularize today's de-facto container image standard, the "Docker container", which has since been accepted as a proper standard and renamed to "OCI image format"; but at the end of the day, at this point in time, Docker in itself is still just a company out for the money, and the multi-GB installation of their product can, for the essential functionality part, be replaced by a few hundred lines of Bash code. The cool boys today don't use Docker, they use [Podman(, which is essentially a much more lightweight drop-in replacement ;-) )
  • `COPY –chmod` reduced the size of my container image by 35%
    7 projects | | 25 Mar 2022
    I think the OP is confusing the runtime and image format a bit here. At runtime OverlayFS can use metadata-only copy up to describe changed files, but the container image is still defined as a sequence of layers where each layer is a tar file. There's no special handling for metadata-only changes of a file from a parent layer. As the OCI image spec puts it [1]:

    > Additions and Modifications are represented the same in the changeset tar archive.


  • Criticize My Dockerfile
    2 projects | /r/docker | 27 Nov 2021
    You don't have any LABELs. Consider the OCI spec:
  • After a couple of months of tinkering and coding, my own self-coded dashboard!
    4 projects | /r/selfhosted | 1 Oct 2021
    Great app. I'd really like to see it developed and improved. Docker image is quite properly done: multi-stage build and user (not root) running application. Just add LABELs according to OCI Image Format Specification and maybe a HEALTHCHECK, and it will be a perfect model.

What are some alternatives?

When comparing init-snapshot and image-spec you can also consider the following projects:

skopeo - Work with remote images registries - retrieving information, images, signing content

nixpacks - App source + Nix packages + Docker = Image

ovh-ipxe-customer-script - Boot OVH server with your own iPXE script

distroless - 🥑 Language focused docker images, minus the operating system.

go-containerregistry - Go library and CLIs for working with container registries

dive - A tool for exploring each layer in a docker image

flyctl - Command line tools for services


asmttpd - Web server for Linux written in amd64 assembly.

fpm - Effing package management! Build packages for multiple platforms (deb, rpm, etc) with great ease and sanity.

bocker - Docker implemented in around 100 lines of bash

docker-lock - Automatically manage image digests in Dockerfiles, docker-compose files, and Kubernetes manifests by tracking them in a separate Lockfile