Posts tagged: docker

Today I learned that docker creates an empty /.dockerenv file to indicate that you are running in a docker container. Other runtimes like podman commonly use /run/.containerenv. kubernetes uses neither of these, the most common way to detect if you are running in kubernetes is to check for the presence of the KUBERNETES_SERVICE_HOST environment variable. There will also be a directory at /var/run/secrets/kubernetes.io/serviceaccount that contains the service account credentials if you are running in kubernetes.

I learned to today that setting MEMORY on your minecraft server causes the JVM to egregiously allocate all of that memory. Not setting it causes slow downs and potential crashes, but setting INIT_MEMORY and MAX_MEMORY gives us the best of both worlds. It is allowed to use more, but does not gobble it all up on startup.

In this economy we need to save all the memory we can!

Here is a non-working snippet for a minecraft server deployment in kubernetes.

containers: - name: dungeon image: itzg/minecraft-server env: - name: EULA value: "true" - name: INIT_MEMORY value: "512M" - name: MAX_MEMORY value: "3G"

and in docker compose

Diun, looks like a very interesting tool to monitor for image updates, it does not make any change, it only makes notifications. This feels like an easy start to getting image updates started with low effort, keep git ops, but requires manual updates. I see this as a tool that would be a great start and pair well with automated image updaters to ensure they are working as expected.

I recently noticed that my og images were missing emoji. They were taken using headless chrome in a container. I fixed it by adding an emoji font in the containerfile / dockerfile.

RUN apt-get update && apt-get install -y \ # Add fonts with emoji support fonts-noto-color-emoji \ && rm -rf /var/lib/apt/lists/*

Before #

Here’s what they were looking like with broken emoji fonts.

And now with the fixed emoji font.

I put thought bubbles on my thoughts posts and stars on my github stars posts

Today I learned that the docs in postiz are a bit behind, (fantastic docs btw, they are to the point, and cover almost all of what you need). The docs state that you need to include an R2 bucket to handle uploads.

This issue shows that more work has been done, one of which is local storage. The compose file they use in the quick start has the required env variables to set this up.

STORAGE_PROVIDER: "local" UPLOAD_DIRECTORY: "/uploads" NEXT_PUBLIC_UPLOAD_DIRECTORY: "/uploads"

looking into my running instance I can see my images there.

Dang context can really cause you to pull your hair out. Context seems so freaking convenient, but I’ve avoided it and just ssh in for these reasons. Maybe I’ll come around eventually but for now ssh is my friend.

Nice example of adding a healthcheck to fastapi, and integrating it with docker. Don’t forget to include curl in the install, nice touch.

bootc is the underlying technology that enables OS’s like bazzite, and Aurora from the uBlue ecosystem.

Hynek has a sick dockerfile setup for using uv in python projects.

This page is gold. It lays out all of the distrobox assemble api with some good examples of how to get access to things like podman and kind from inside of containers.

Especially this example.

Today I learned that you can use init_hooks to access host machine commands from inside a distrobox container. This is super handy for things that you cannot get to from inside the container and need ran outside (docker, podman, flatpak, xdg-open).

Docker no Docker, what!!!

So fly.io uses Dockerfiles to deploy your app, but no docker. They use containerd to download your docker images into firecracker microvms to run your app. Firecracker is the same tech that runs aws lambda functions.

Fascinating short post on the beans under the hood at fly.io and how they scale your app globally.

Great listen for anyone interested in productionizing python code with docker. Itamar brings up some

Don’t trust base images for security, upgrade your packages. Vulnerabilties become published and solved giving the bad guys istructions how to wreck your day and these fixes wont come to your docker application for up to two weeks due to image build tatency.

For job based containers pre-compile your pyc for faster startup.

Alpine linux is probably not what you want for python. Many packages such as postgres ship pre-copiled binaries that work for most linux distributions wich use glibc, but alpine uses musl so the binaries will be incompatable requiring you to need to install a bunch of build dependencies.

The convention of “z-pages” comes from google and reduces the likelihood of collisions with application endpoints and keep the convention across all applications.

I’ve been using this for a few weeks now and it’s fantastic. It’s reminds me of lazygit, it gives a nice quick interface into the things I need and it just works. Yes I can git status to see what changed, then diff the files, then commit hunks, but lazygit can do that in just a few keystrokes. lazydocker does this for docker. It gives me a nice view into whats running, what’s eating up disk space, and the networks I have. And if I see I have a bunch of exited containers, there is a bulk command righ there to clean them up.

tldr docker ps on steroids

Really cool tui to inspect docker imaages that runs with docker.

A very straightforward guide to moving your docker data, such as container storage to a different location. In my case I wanted it off of my boot drive.

On void linux. Under `/etc/containers/` there is a file called `registries.conf`. It is complemented by `man 5 containers-registries.conf`. Change (for me lines 11-12) which say [registries.search] registries = [] to

[registries.search] registries = ['docker.io']

(drawn from https://www.projectatomic.io/blog/2018/05/podman-tls/)