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It doesn't. Imagine you just want to run some utility written in Python (let's use youtube-dl since it is been on front page lately), why do I need to install D

It doesn't. Imagine you just want to run some utility written in Python (let's use youtube-dl since it is been on front page lately), why do I need to install Docker to run a simple command? For isolation? No thanks. Virtualenv was created to isolate overwrittkng and installing dependencies. Also, want to emulate multi-sites on single machine deployment? You need virtualenv.

icebraining 9y ago
Docker does solve those problems, even if you and I prefer to use other solutions. And by the way, you don't actually need virtualenv :) we run multiple webapps on a machine by just installing dependencies in a directory (pip -t) in the git repo, and then adding the appropriate PYTHONPATH in the service's startup config. As long as you don't need multiple versions of the Python interpreter, this works fine.
- eeZah7Ux 9y ago
  > Docker does solve those problems ...with a very computationally expensive solution, and without improving other aspects like security. A systemd unit on a "chroot" can do the same and provide isolation.
  - floatboth 9y ago
    Is it really computationally expensive? Containers/jails/zones are essentially chroots "on steroids", isolating things other than the filesystem (networking, hostname, process IDs, users, etc.)
    - 0xCMP 9y ago
      Once built a docker container is not expensive, but the idea with Docker is to create immutable, layered containers and rebuilding every time there is a change. Unlike with nodejs, it's harder to volume mount python packages installed in the docker container and so no one does it. Change in requirements means rebuilding the container which is a very computationally and IO expensive process. So if you can get away with it virtualenv is better, but putting everything in a container so you can simply ship a container is also useful. It's a compromise.
      - icebraining 9y ago
        Rebuilding the container shouldn't be expensive, that's what layers are for.
        0xCMP 9y ago
        A layer with your pip requirements being added and then installed is the most expensive part of building a python container so if you change your requirements you invalidate the cache for that layer (and possibly the other layers above).

icebraining 9y ago

Docker does solve those problems, even if you and I prefer to use other solutions. And by the way, you don't actually need virtualenv :) we run multiple webapps on a machine by just installing dependencies in a directory (pip -t) in the git repo, and then adding the appropriate PYTHONPATH in the service's startup config. As long as you don't need multiple versions of the Python interpreter, this works fine.

eeZah7Ux 9y ago
> Docker does solve those problems ...with a very computationally expensive solution, and without improving other aspects like security. A systemd unit on a "chroot" can do the same and provide isolation.
- floatboth 9y ago
  Is it really computationally expensive? Containers/jails/zones are essentially chroots "on steroids", isolating things other than the filesystem (networking, hostname, process IDs, users, etc.)
  - 0xCMP 9y ago
    Once built a docker container is not expensive, but the idea with Docker is to create immutable, layered containers and rebuilding every time there is a change. Unlike with nodejs, it's harder to volume mount python packages installed in the docker container and so no one does it. Change in requirements means rebuilding the container which is a very computationally and IO expensive process. So if you can get away with it virtualenv is better, but putting everything in a container so you can simply ship a container is also useful. It's a compromise.
    - icebraining 9y ago
      Rebuilding the container shouldn't be expensive, that's what layers are for.
      - 0xCMP 9y ago
        A layer with your pip requirements being added and then installed is the most expensive part of building a python container so if you change your requirements you invalidate the cache for that layer (and possibly the other layers above).