Ongoing Investigations

Tag: docker

  • Containers Workshop Week 1: Hello, World!

    Just using this space quickly to type up some thoughts about Week 1 of the containers workshop we hosted in July. For a variety of reasons I’m only now getting the opportunity to work through the exercises, one week at a time, so here we go.

    Week 1 covered an introduction to containers: what they are, why they’re useful, where the idea comes from, and how to get started. Jim likened digital containers, which I often reductively describe as “scalable micro-servers”, to real-life shipping containers: a way to package a specific thing or set of things (in this case, softwares) in a way that keeps them isolated and secure, that standardizes how things are organized, that keeps them flexible and easy to rearrange, and that reduces the cost of (in real life) shipping or (on the web) hosting.

    Getting started meant going through the Reclaim Cloud interface, which I was already somewhat familiar with. We covered how to locate the Settings area, how to set up a new container using the marketplace, where that container and its nodes (component sub-containers) live, and how to access the settings, configuration, and terminal for a given node.

    The exercise for the week was to set up a Docker container using the marketplace’s installer and then use the terminal to run the command docker run hello-world. The tutorial video also showed how to poke around inside the environment topology, how to find a given container’s settings and file manager, how to create new files and folders, and several other things.

    This was a good combination refresher-intro — it helped me refamiliarize myself with tools I’d already used and understand a little more about how they work and what they’re made up of. It was also useful from a terminology standpoint, as that’s often where I’ve had issues in the past — while I can conceptualize things, understanding what a person or a tutorial is referring to with a given term can be really difficult for me.

    Questions and Takeaways:

    • I was still pretty unclear on what actually happened when I ran the docker run hello-world command. Something definitely ran, because the terminal printed out some introductory information, but when I navigated to the URL for my environment, I got an error that nothing was there.
    • While the container can just run the command and stop, it’s still active in the background and using resources — so what’s it using them for, if it isn’t doing anything?
    • How would I set up/program an environment to continue running indefinitely? I know it’s possible because that’s how Reclaim Cloud applications run, but I don’t know what I would need to do if I wanted to develop my own little application.
    • For that matter, how would I build custom Docker images for those little applications?
    • I need to review setting up SSH keys so that I can choose between the Reclaim Cloud terminal and my local terminal if I want.

  • Docker for Beginners: Hello, World!

    Today I got started exploring Docker for the first time, using A Docker Tutorial for Beginners. Reclaim Cloud runs using Docker containers, and a few of us will be doing some research on it in the next month or so, so it seemed like a good thing to try.

    Docker is, as I understand it, a system for running containers, which are a less resource-intensive alternative to virtual machines. You can spin up a container using a particular system, run it while you’re using it and pause it while you’re not, and interact with it through the command line.

    I spent most of today messing around with the Docker Desktop interface, which I found extremely frustrating — the tutorial itself was lovely, but… essentially, I understand that documentation is usually aimed at the lowest common denominator, but today I wish they had aimed a bit lower. Specifically, nearly all of the features that the documentation offered instructed you to click on a button shaped like a tiny whale, which would open a pulldown menu of options that you could then choose from. It took me forty-five minutes and another person’s help to find the tiny whale, which turned out to have been placed not anywhere in the actual window of Docker Desktop, but in my menu bar at the very top of the page, where it could blend in neatly with my clock, my battery and my Wi-Fi indicator.

    Today I worked up through the Hello, World! section of the tutorial, which got me through both how to set up Docker & Docker Desktop, and what some of the basic concepts and tools of Docker are. To the best of my understanding, Images are a bit like modules or applications – they tell Docker what any container modeled on that image will be capable of doing. Meanwhile, Containers are individual instances in which to run your programs.

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