buildkit VS crun

> We are uding docker-in-docker at the moment

You can also run a "less privileged" container with all the features of Docker by using rootless buildkit in Kubernetes. Here are some examples:

https://github.com/moby/buildkit/tree/master/examples/kubern...

https://github.com/moby/buildkit/blob/master/examples/kubern...

It's also possible to run dedicated buildkitd workers and connect to them remotely.

- BuildOp evaluates its input as additional LLB operations to add to the graph to allow for dynamic build graphs (also unused in the Dockerfile frontend)

With the Dockerfile Explorer, we run the Dockerfile frontend[1] that BuildKit uses inside of WASM to parse and produce the LLB output locally in your browser. We then embed the Monaco Editor so that you can change your Dockerfile to see how it impacts the LLB output that BuildKit will use to build your Docker image.

You can see a quick video and read more details on how it all works here: https://depot.dev/blog/dockerfile-explorer.

We'd love any feedback or ideas folks would like around this type of tool!

[0] https://github.com/moby/buildkit#exploring-llb

Now since Kubernetes works off of containerd I'll be taking a different approach on handling container builds by using nerdctl and the buildkit that comes bundled with it. I'll do this on the amd64 control plane node since it's beefier than my Raspberry Pi workers for handling builds and build related services. Go ahead and download and unpack the latest nerdctl release as of writing (make sure to check the release page in case there's a new one):

There's a 2-year-old moby/buildkit GitHub issue about frequent build cache misses when using the BuildKit docker-container driver and multi-stage builds. Anyone else in this sub run into this problem and/or have reasonable workarounds? It seems like something that should come up pretty often.

A couple months ago I encountered a bug in buildkit - when enabling OpenTelemetry tracing, we got occasional panics. With a bit of investigation, we found the cause, fixed and tested in our fork and internal deployments, and pushed to upstream.

I do some search in the internet and there seems to be no good solution, so I just create a feature request: https://github.com/moby/buildkit/issues/3859

Yeah, only Linux containers at the moment, BuildKit is the way we are constructing pipelines and doing caching. Split on if we will support non-linux hosts, but definitely want to find a good solution to not doing Docker-in-Docker.

Relevant issues are https://github.com/moby/buildkit/issues/3011 and https://github.com/moby/buildkit/issues/1512.

Yep pretty much.

The executables bundle crun (a container runtime)[0], and a fuse implementation of squashfs and overlayfs. Appended to that is a squashfs of the image.

At runtime the squashfs and overlayfs are mounted and the container is started.

[0]: https://github.com/containers/crun

cpu: 4 disk: 60 memory: 12 arch: host hostname: colima autoActivate: true forwardAgent: false # I only tested this with 'docker', not 'containerd': runtime: docker kubernetes: enabled: false version: v1.24.3+k3s1 k3sArgs: [] network: address: true dns: [] dnsHosts: host.docker.internal: host.lima.internal # Added: # - containerd-snapshotter: true (meaning containerd will be used for pulling images) # - default-runtime / runtimes: crun (instead of the default 'runc') docker: default-runtime: crun features: buildkit: true containerd-snapshotter: true runtimes: crun: path: /usr/local/bin/crun vmType: vz rosetta: true mountType: virtiofs mountInotify: false cpuType: host # This provisioning script installs WasmEdge and builds crun with wasmedge support: provision: - mode: system script: | [ -f /etc/docker/daemon.json ] && echo "Already provisioned!" && exit 0 echo "Install system updates:" apt-get update -y apt-get upgrade -y echo "Install WasmEdge and crun dependencies:" # NOTE: packages curl git python3 already installed: apt-get install -y make gcc build-essential pkgconf libtool libsystemd-dev libprotobuf-c-dev libcap-dev libseccomp-dev libyajl-dev libgcrypt20-dev go-md2man autoconf automake criu apt-get clean -y - mode: user script: | [ -f /etc/docker/daemon.json ] && echo "Already provisioned!" && exit 0 echo "Installing WasmEdge:" curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | sudo bash -s -- -p /usr/local echo echo "`wasmedge -v` installed!" # NOTE: I failed to Configure Wasmtime properly - turned off for now: #echo "Installing Wasmtime:" #curl -sSf https://wasmtime.dev/install.sh | bash #sudo cp .wasmtime/bin/* /usr/local/bin/ #rm -rf .wasmtime #echo "`wasmtime -V` installed!" echo "Install crun:" git clone https://github.com/containers/crun cd crun ./autogen.sh #./configure --with-wasmedge --with-wasmtime ./configure --with-wasmedge make sudo make install crun -v echo "crun installed! Replacing runc with crun:" # NOTE: replacing runc with runc is to simplify containerd config TRC=`which runc` sudo rm -rf $TRC sudo cp `which crun` $TRC echo "Configuring containerd:" sudo mkdir -p /etc/containerd/ containerd config default | sudo tee /etc/containerd/config.toml >/dev/null echo "Restarting/reloading docker/containerd services:" sudo systemctl daemon-reload sudo systemctl restart containerd # As soon as Colima writes its /etc/docker/daemon.json file (right after this provisioning script), # it will also start the Docker daemon. If we stop Docker here, the changes will actually take effect: sudo systemctl stop docker sshConfig: true mounts: [] env: {}

On this note, I was really surprised to find Red Hat's OCI runtime is written in C: https://github.com/containers/crun

Is anyone working on a Rust version?

It's interesting that, in light of things like this, you still see large software companies adding support for new components written in non-memory safe languages (e.g. C)

As an example Red Hat OpenShift added support for crun(https://github.com/containers/crun) this year(https://cloud.redhat.com/blog/whats-new-in-red-hat-openshift...), which is written in C as an alternative to runc, which is written in Go(https://github.com/opencontainers/runc)...

Kubernetes needs an OCI runtime to run containers with. Crun is one implementation it can use.

Docker also appears to be able to use crun for it's engine as well. https://github.com/containers/crun/issues/37

crun

Looks like https://github.com/containers/crun/issues/255 - start there.