containerd VS nerdctl

Containerd and nerdctl

Kubernetes on the backend used to utilize docker for much of its container runtime solutions. One of the modular features of Kubernetes is the ability to utilize a Container Runtime Interface or CRI. The problem was that Docker didn't really meet the spec properly and they had to maintain a shim to translate properly. Instead users could utilize the popular containerd or cri-o runtimes. These follow the Open Container Initiative or OCI's guidelines on container formats.

Container Engine: A runtime that executes and manages containers. Docker and containerd are popular container engines.

Multiple container runtimes are supported, like conatinerd, cri-o, or other CRI compliant runtimes.

This is a failed attempt to upstream part of containerd changes: https://github.com/containerd/containerd/pull/8789

Other part of containerd changes waits for gods-know-what: https://github.com/containerd/containerd/pull/9054

But I haven't gave up yet.

containerd is required by kubernetes to handle containers on its behalf. A big thanks to the HostAfrica blog for the information on setting containerd up for debain. So the containerd install will need to happen on both the WSL2 instance and the Raspberry Pis. For WSL2 you can just install containerd directly:

The context deadline exceeded: unknown is also in containerd, and is a known problem.

Get:1 https://download.docker.com/linux/ubuntu focal/stable amd64 containerd.io amd64 1.6.21-1 [28.3 MB]

Docker Desktop adds a bunch of stuff to simplify local development and that’s why it has a larger memory footprint. You don’t use that when deploying but something like https://containerd.io/.

What about the docker-cli? colima also ships with a docker-compatible cli to interact with containerd called nerdctl. We can execute the same docker cli commands like:

Using nerdctl: https://github.com/containerd/nerdctl

I'd really disagree that compose files are somehow one-shot, or blindly modified. To the contrary, really, we have them checked in with the source code. Upon deployment to the cluster, the (running) services will be intelligently updated or replaced (in a rolling manner, causing zero downtime). LXC might be more elegant, but I have no idea what simple, file-based format I could use to let engineers describe the environment their app should run in without compose.

I need something that even junior devs can start up with a single command, that can be placed in the VCS along with the code, and that will not require deep Linux knowledge to get running. Open for suggestions here, really.

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):

That's why nerdctl, their cli binary, is so well named.

Well, it is indeed a good option. However, containerd is a good alternative that is growing even among developers. Please see: https://github.com/containerd/nerdctl

Nerdctl/containerd has IPFS support :)

https://github.com/containerd/nerdctl/blob/main/docs/ipfs.md

nerdctl supports IPFS for both image pulling and pushing, including encrypted images and eStargz lazy pulling. For building, the current method is a locally hosted translator so that the traditional pulls can be converted to work over IPFS. They even have docs on running it on k8s node, though if my reading is correct this isn't exactly a cloud native approach (running systemd services on each node...).