Develop Reference

how to mount a local volume for my docker?

i am newbie to the Linux and docker. I am using the below command to run the docker:
sudo nvidia-docker run --gpus all -p 8888:8888 -it -v /home/pyman/PEYMAN:??????? 21bbc6c8f7ed
where; /home/pyman/PEYMAN is my local directory
and 21bbc6c8f7ed is the image ID.
after running this command, the workspace root changes to root#0ce2ee24bac0:/workspace#
then I type jupyter notebook and run it, and it provides two links which only the second link opens the jupyter notebook in the browser.
http://hostname:8888/?token=xxxxxxxxxxx
http://127.0.0.1:8888/?token=xxxxxxxxxxx
but I dont know what is my container_dir in the first command to put in ?????, and how to get the directory. is the container_dir the same directory that jupyter is?

The container_dir is the path inside the container, where you'd like to see your mounted files. The directory inside container does not even have to exist, yon can pick almost any place to mount your files. If you work with jupyter, it makes sense to add your files to the working directory:
docker run -v /home/pyman/PEYMAN:/workspace/myfiles
Once inside the container you will find /home/pyman/PEYMAN in /workspace/myfiles.

Calling Docker command within Dockerized app

It's been asked before but I haven't been able to find the answer so far. I have a script which is called via a Flask app. It's Dockerized and I used docker-compose.yml. The docker command, which worked outside of Docker, creates a html file using openscad. As you can see below, it takes a variable path:
cmd_args = f"docker run -v '{path}':/documents/ --rm --name manual-asciidoc-to-html " \
f"asciidoctor/docker-asciidoctor asciidoctor -D /documents *.adoc"
Popen(cmd_args, shell=True)
time.sleep(1)
When the script executes, the print out in Terminal shows:
myapp | /bin/sh: 1: docker: not found
How can I get this docker command to run in my already running docker container?

I don’t really get what you are trying to say here but I‘m assuming you want to run the docker command from within your container. You don’t really do it that way. The way to communicate with the docker daemon from within a container is to add the Docker Unix socket from the host system to the container using the -v when starting the container or adding it to the volumes section of your docker-compose:
volumes:
- /var/run/docker.sock:/var/run/docker.sock
After doing that you should be able to use a docker API (https://github.com/docker/docker-py) to connect to the Daemon from within the container and do the actions you want to. You should be able to convert the command you initially wanted to execute to simple docker API calls.
Regards
Dominik

Configuring a dockerfile to 'read' from a directory?

I am building a webapp (a simple flask site) that uses docker. I want my development code to not reside within docker, but be executed by the development environment (using python3) I have defined in my dockerfile. I know that I can use the COPY . . syntax in a dockerfile to copy my source code into the image for execution, but that violates my aim of separating the container from my source. Is there a way to have a docker container read and execute the code that it is in the directory I run the docker container run command from?
Right now my container uses the copy company to copy all the source code into the container. It then uses the CMD command to automatically run the flask app:
CMD [ "python", "flask_app/server.py" ]
(I'm storing all my flask code in a directory called flask_app). I'm assuming this works because all this has been copied into the container (according to the specifications given in the dockerfile) and is being executed when I run the container. I would like for the container to instead access and execute flask_app/server.py without copying this information into itself -- is this possible? If so, how?

Instead of using COPY to move the code into the container, you'll use a "bind mount" (https://docs.docker.com/storage/bind-mounts/).
When you run the container, you'll do it with a command like this:
docker run --mount type=bind,source=<path_outside_container>,target=<path_inside_container> <image_tag>
For portability, I recommending putting this line in a script intended to be run from the repository root, and having the <path_outside_container> be "$(pwd)", so that it will work on other people's computers. You'll need to adjust <path_inside_container> and your CMD depending on where you want the code to live inside the container.
(Obviously you can also put whatever other options you'd like on the command, like --it --rm or -p <whatever>.)

Setting up graph-tool on Docker Toolbox for WIndows

I followed the graph-tool docker installation instructions here. I've set up Docker Toolbox (can't use Docker for Windows, not on Pro), and I've gotten jupyter running with the Docker image.
However, I need to access a notebook in my C: drive. For the sake of this post let's say the notebook is in C:\Users\Gab\Desktop. I've successfully moved into that location, but when I run the command docker run -p 8888:8888 -p 6006:6006 -it -u user -w /home/user tiagopeixoto/graph-tool bash, it opens a bash in /home/user, not in the directory I cd'd into previously.
From what I understand, the -w /home/user is what tells it where to open, but I'm not sure how to tell it to open in the Desktop folder.
How can I set things up properly so that I can run the command jupyter notebook --ip 0.0.0.0, and still be able to access the notebook I need?
Thanks!

Here's the deal with Docker. When you execute the docker run command, what happens is that an entirely new subsystem is created which is separate from your host Operating System ( this is known as a Docker container ). This subsystem runs the tiagopeixoto/graph-tool image in it so hence the graph-tool ( and hence jupyter-notebook ) and the entrypoint /home/user is present inside this system instead of the host OS you use to run the Docker container ( in your case its Windows ). Unfortunately for you the notebook that you wish to view using jupyter-notebook isn't present inside the container and is located elsewhere ( Windows to be exact ).
What you can do in this case is mount a folder of the host Operating System to the container such that this folder contains the notebook you wish to view :-
Open a new command prompt, and type in this command as follows :- docker run -p 8888:8888 -p 6006:6006 -v /c/Users/Gab/Desktop:/mnt/temp/ -it -u user -w /home/user tiagopeixoto/graph-tool bash
The main difference to note here is the -v switch which mounts the C:\Users\Gab\Desktop volume from the host system to the Docker container in /mnt/temp/. Once that is done try viewing the notebook present in /mnt/temp in jupyter-notebook.
According to this post there exists an issue related to mounting a volume in Windows, so please check this out as well :- docker toolbox mount file on windows

Why does django inside a container needs the "it" flag?

I try to run django on a docker container using sqllite as the db and the django dev server. So far I was able to launch locally the django server:
python .\manage.py runserver
I can build the docker image using Dockerfile:
docker build . -t pythocker
But when I run the image with docker run -p 8000:8000 pythocker no output is shown and the machine is not reachable, I have to kill the running container.
If I add the -it flag on the docker run command then the server is running and I can go to http://192.168.99.100:8000 and display the django welcome page. Why is this flag mandatory here?
Docker logs on the container gives nothing. I also tried to add custom logging inside the manage.py but it's not diplayed in the console or in the docker logs.
I am using the Docker Windows toolbox as I have only a windows home computer.