cri-dockerd VS compose-spec

$ wget https://github.com/Mirantis/cri-dockerd/releases/download/v0.3.9/cri-dockerd-0.3.9.amd64.tgz $ tar zxvf cri-dockerd-0.3.9.amd64.tgz $ cd cri-dockerd $ sudo mkdir -p /usr/local/bin $ sudo install -o root -g root -m 0755 cri-dockerd/usr/local/bin/cri-dockerd $ mkdir foo; cd foo $ git clone [email protected]:Mirantis/cri-dockerd.git $ cd cri-dockerd $ sudo install packaging/systemd/* /etc/systemd/system $ sudo sed -i -e 's,/usr/bin/cri-dockerd,/usr/local/bin/cri-dockerd,' /etc/systemd/system/cri-docker.service $ sudo systemctl daemon-reload $ sudo systemctl enable --now cri-docker.socket

I installed cri-dockerd using this documentation https://github.com/Mirantis/cri-dockerd

99% of what you just said is completely incorrect. containerd is not a facade for Docker, in fact the Docker engine is a facade for containerd. The OCI spec is also not a facade for Docker, Docker is simply one application which can create OCI compliant images which can be executed by runtimes like runc. Kubernetes has zero facades for Docker, unless you count the optional open-source cri-dockerd.

https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/ Adjust netplan for static IP Adding br_netfilter and overlay to kernel Creating /etc/modules-load.d/k8s.conf with bridging and forwarding https://kubernetes.io/docs/setup/production-environment/container-runtimes/#forwarding-ipv4-and-letting-iptables-see-bridged-traffic Installing docker components https://kubernetes.io/docs/setup/production-environment/container-runtimes/#docker Installing cri-dockerd https://github.com/Mirantis/cri-dockerd Disabling swap https://graspingtech.com/disable-swap-ubuntu/ install kubeadm kubectl kubelet https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

Im trying to learn how to set up kubernetes cluster with kubeadm. Im using official kubernetes documentation ( maybe there is a better source?). My goal is to set it up with cri-dockerd and systemd. And to be honest its quite hard task to do it. Informations are scattered arround with links and sometimes its hard to know the order which steps should be executed. I have 2 Virtualbox machines, connected together with NAT network. A master and worker node. I performed these steps on both of them: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/ Adjust netplan for static IP Adding br_netfilter and overlay to kernel Creating /etc/modules-load.d/k8s.conf with bridging and forwarding https://kubernetes.io/docs/setup/production-environment/container-runtimes/#forwarding-ipv4-and-letting-iptables-see-bridged-traffic Installing docker components https://kubernetes.io/docs/setup/production-environment/container-runtimes/#docker Installing cri-dockerd https://github.com/Mirantis/cri-dockerd Disabling swap install kubeadm kubectl kubelet https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/ configure kubelet cgroup driver https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/configure-cgroup-driver/ So currently im at the configuring cgroup driver. I tried to execute kubeadm init kubeadm-config.yaml but kubeadm found 2 CRI endpoints. So i tried to point the correct one with this command kubeadm join --cri-socket /var/run/cri-dockerd.sock but i got discover:Invalid value: ::: bootstrapToken or file must be set And now im completely lost. And also im confused is this a moment for installing CNI (probably i will try with Calico) for pod communication or should i start the cluster first?

But not to worry, you can still use Docker as a container runtime in Kubernetes using the cri-dockerd adapter. cri-dockerd provides a shim for Docker Engine that lets you control Docker via the Kubernetes CRI. ****

As of version 1.24, either one of the other supported runtimes (e.g. containerd or CRI-O) or, in case you still want to rely on Docker Engine, cri-dockerd must be used. Further information on precautions that may be necessary due to the removal of Dockershim is provided by Kubernetes in a guide.

Kubernetes requires a tool which implements the Container Runtime Interface, a standardized API for starting & managing containers. This is from 2015-2016[1].

For a while Kubernetes has included something called the "dockershim", it's own implementation of a CRI interface that, under the hood, calls Docker or Podman. There's also tools like kind[2] ("kubernetes in docker") that go further- not just hosting Kubernetes worker containers in Docker, but hosting the main kubernetes daemons also in Docker.

Kubernetes deprecated Dockershim, formally in December 2020, but is just throwing the switch now in the upcoming 1.24, expected mid-April[3]. A company Mirantis has pledged to take over support of Dockershim[4], and is calling the new effort "cri-dockerd"[5]. This should allow Kubernetes workers to continue to run via Docker or Podman.

Kind is unaffected, since it runs the main Kubernetes controllers in Docker, which then launch their own opencontainerd (one off the main CRI implementations) inside that Docker container, nested like, so no dockership/cri-dockerd is needed).

[1] https://kubernetes.io/blog/2016/12/container-runtime-interfa...

[2] https://kind.sigs.k8s.io/

[3] https://kubernetes.io/blog/2022/01/07/kubernetes-is-moving-o...

[4] https://www.mirantis.com/blog/mirantis-to-take-over-support-...

[5] https://github.com/Mirantis/cri-dockerd

Specification: https://compose-spec.io

https://github.com/compose-spec/compose-spec/blob/master/spe...

There are a number of incorrect statements in this post.

1) One should neither be using the "latest" nor just the "version" tag as the version can still vary depending on when it is pulled.

Instead, one should use a combination of version + hash, say alpine:3.18.2@sha256:82d1e9d7ed48a7523bdebc18cf6290bdb97b82302a8a9c27d4fe885949ea94d1 for reproducibility reasons. This provides for human readable versions as well as the specific hash.

2) Next, afaik, Compose has removed the need for version tags. All of the compose.yml files that I now use do not specify versions.

See https://github.com/compose-spec/compose-spec/blob/master/04-...

Docker Compose v2 specifications provide a useful Secrets feature which may also be used for standalone Compose Application Stacks and not just in Docker Swarm mode. With Docker Secrets the environment variables that contain credentials for other subsystems are mounted into the Telegraf Container as files. These secret files are read through the Docker Secret Store plugin and passed to the respective plugins in a relatively safe manner. By using the Docker Secret Store Plugin, one can also avoid credentials that were previously visible via environment variables, to be now hidden behind runtime secret files within the container. Standard Method with Environment Variables As an example, it is possible to pass the credentials to a plugin via the environment variable placeholder in a telegraf configuration file where the credentials for a plugin exist in a .env file (e.g. MQTT input Plugin)

also the docker-compose.yml file is very picky about what you have in it and where. Please read this so you know how to format it https://github.com/compose-spec/compose-spec/blob/master/spec.md

As part my quadlet helper tool, podlet, I'm adding functionality to convert compose files into k8s yaml to use with quadlet as an alternative to creating a bunch of separate quadlet files, which I've also added functionality for. So I would like to be able to transform the options on compose volumes into k8s yaml. For example, using the volume.podman.io/driver annotation to change the volume driver for a specific volume if possible.

If you find this helpful feature, please leave your feedback and suggestions here.

The compose spec will give what you need. https://github.com/compose-spec/compose-spec/blob/master/spec.md

Indeed, as per the compose-spec a lot of what was version specific is going away

Hello everyone, I just made a tool to visualize compose files, and all the parsing rules follow the [compose-spec](https://github.com/compose-spec/compose-spec/blob/master/spec.md). I hope this tool will help you :D