Is it possible to share a volume with 2 docker containters? - python

I can't run 2 containers whereas I can run each one them separately.
I have this 1st container/image related to this DockerFile
FROM debian:latest
RUN apt-get update && apt-get install python3-pip -y && pip3 install requests
ADD test1.py /app/container1/test1.py
WORKDIR /app/
CMD python3 container1/test1.py
I have this 2nd container/image related to this DockerFile
FROM debian:latest
RUN apt-get update && apt-get install python3-pip -y && pip3 install requests
ADD test2.py /app/container2/test2.py
WORKDIR /app/
CMD python3 container2/test2.py
No issues to create images:
docker image build ./authentif -t test1:latest
docker image build ./authoriz -t test2:latest
When I run the 1st container with this command:
docker container run -it --network my_network --name test1_container\
--mount type=volume,src=my_volume,dst=/app -e LOG=1\
--rm test1:latest
it works.
And If i want to check my volume:
sudo ls /var/lib/docker/volumes/my_volume/_data
I can see data in my volume
However when I want run the 2nd container:
docker container run -it --network my_network --name test2_container\
--mount type=volume,src=my_volume,dst=/app -e LOG=1\
--rm test2:latest
I have this error:
python3: can't open file '/app/container2/test2.py': [Errno 2] No such file or directory
If i delete everything and start over : if I start running the 2nd container it works but then id I want to run the 1st container, i have the error again.
why is that?
in my container1, let's assume that my script python writes data in a file, for example :
import os
print("test111111111")
if os.environ.get('LOG') == "1":
print("1111111")
with open('record.log', 'a') as file:
file.write("file11111")

I can't reproduce your issue. When I start 2 containers using
docker run -d --rm -v myvolume:/app --name container1 debian tail -f /dev/null
docker run -d --rm -v myvolume:/app --name container2 debian tail -f /dev/null
and then do
docker exec container1 /bin/sh -c 'echo hello > /app/hello.txt'
docker exec container2 cat /app/hello.txt
it prints out 'hello' as expected.

You are mounting the volume over /app, the directory that contains your application code. That hides the code and replaces it with something else.
The absolute best approach here, if you can handle it, is to avoid sharing files at all. Keep the data somewhere like a relational database (which may be stateful). Don't mount anything on to your containers. Especially if you're looking forward to a clustered environment like Kubernetes, sharing files can be surprisingly tricky.
If you can't get rid of the shared directory, then put it somewhere other than /app. You might need to configure the alternate directory using an environment variable.
docker container run ... \
--mount type=volume,src=my_volume,dst=/data \ # /data, not /app
...
What's actually happening in your setup is that Docker has a feature to copy the contents of the image into an empty named volume on first use. This only happens if the volume is completely empty, this only happens with a named Docker volume and not bind mounts, and this doesn't happen on other container systems like Kubernetes. (I'd discourage actually relying on this behavior.)
So when you run the first container, it sees that my_volume is empty and copies the test1 image into it; then the container sees the code it expects it in /app and it apparently works fine. The second container sees my_volume is non-empty, and so the volume contents (with the first image's code) hide what was in the image (the second image's code). I'd expect, if you started from scratch, whichever of the two containers you started first would work, but not the other, and if you change the code in the working image, a new container won't see that change (it will use the code out of the volume).

Related

Docker : Add a valid entrypoint for multiple python script

Helli, I have to build a Docker image for the following bioinformatics tool: https://github.com/CAMI-challenge/CAMISIM. Their dockerfile works but takes a long time to build and I would like to build my own, slightly differently, to learn. I face issues: there are several python script that I should be able to choose to run, not only a main. If I add one script in particular as an ENTRYPOINT then the behavior isn't exactly what I shoud have.
The Dockerfile:
FROM ubuntu:20.04
ENV DEBIAN_FRONTEND=noninteractive
USER root
#COPY ./install_docker.sh ./
#RUN chmod +x ./install_docker.sh && sh ./install_docker.sh
RUN apt-get update && \
apt install -y git python3-pip libxml-simple-perl libncursesw5 && \
git clone https://github.com/CAMI-challenge/CAMISIM.git && \
pip3 install numpy ete3 biom-format biopython matplotlib joblib scikit-learn
ENTRYPOINT ["python3"]
ENV PATH="/CAMISIM/:${PATH}"
This yields :
sudo docker run camisim:latest metagenomesimulation.py --help
python3: can't open file 'metagenomesimulation.py': [Errno 2] No such file or directory
Adding that script as an ENTRYPOINT after python3 allows me to use it with 2 drawbacks: I cannot use another script (I could build a second docker image but that would be a bad solution), and it outputs:
ERROR: 0
usage: python metagenomesimulation.py configuration_file_path
#######################################
# MetagenomeSimulationPipeline #
#######################################
Pipeline for the simulation of a metagenome
optional arguments:
-h, --help show this help message and exit
-silent, --silent Hide unimportant Progress Messages.
-debug, --debug_mode more information, also temporary data will not be deleted
-log LOGFILE, --logfile LOGFILE
output will also be written to this log file
optional config arguments:
-seed SEED seed for random number generators
-s {0,1,2}, --phase {0,1,2}
available options: 0,1,2. Default: 0
0 -> Full run,
1 -> Only Comunity creation,
2 -> Only Readsimulator
-id DATA_SET_ID, --data_set_id DATA_SET_ID
id of the dataset, part of prefix of read/contig sequence ids
-p MAX_PROCESSORS, --max_processors MAX_PROCESSORS
number of available processors
required:
config_file path to the configuration file
You can see there is an error that should'nt be there, it actually does not use the help flag. The original Dockerfile is:
FROM ubuntu:20.04
RUN apt update
RUN apt install -y python3 python3-pip perl libncursesw5
RUN perl -MCPAN -e 'install XML::Simple'
ADD requirements.txt /requirements.txt
RUN cat requirements.txt | xargs -n 1 pip install
ADD *.py /usr/local/bin/
ADD scripts /usr/local/bin/scripts
ADD tools /usr/local/bin/tools
ADD defaults /usr/local/bin/defaults
WORKDIR /usr/local/bin
ENTRYPOINT ["python3"]
It works but shows the error as above, so not so much. Said error is not present when using the tool outside of docker. Last time I made a Docker image I just pulled the git repo and added the main .sh script as an ENTRYPOINT and everything worked despite being more complex (see https://github.com/Louis-MG/Metadbgwas).
Why would I need ADD and moving everything ? I added the git folder to the path, why can't I find the scripts ? How is it different from the Metadbgwas image ?
In your first setup, you start in the image root directory / and run git clone to check out the repository into /CAMISIM. You never change the current directory, though, so when you try to run python3 metagenomesimulation.py --help it's looking in / and not /CAMISIM, hence the "not found" error.
You can fix this just by changing the current directory. At any point after you check out the repository, run
WORKDIR /CAMISIM
You should also delete the ENTRYPOINT line. For each of the scripts you could run as a top-level entry point, check two things:
Is it executable; if you ls -l metagenomesimulation.py are there x in the permission listing? If not, on the host system, run chmod +x metagenomesimulation.py and commit to source control. (Or you could RUN chmod ... in the Dockerfile if you really can't change the repository.)
Does it have a "shebang" line? The very first line of the script should be
#!/usr/bin/env python3
If both of these things are true, then you can just run ./metagenomesimulation.py without explicitly saying python3; since you add the directory to $PATH as well, you can probably run it without specifying the ./... file location.
(Probably deleting the ENTRYPOINT line on its own is enough, given that ENV PATH setting, but your script still might be confused by starting up in the wrong directory.)
The long "help" output just suggests to me that the script is expecting a configuration file name as a parameter and you haven't provided it, or else you've repeated the script name in both the entrypoint and command parts of the container command string.
In the end very little was recquired and the original Dockerfile was correct, the same error is displayed anyway, that is due to the script itself.
What was missing was a link to the interpreter, so I could remove the ENTRYPOINT and actually interpret the script instead of having python look for it in its own path. The Dockerfile:
FROM ubuntu:20.04
ENV DEBIAN_FRONTEND=noninteractive
USER root
RUN ln -s /usr/bin/python3 /usr/bin/python
RUN apt-get update && \
apt install -y git python3-pip libxml-simple-perl libncursesw5 && \
git clone https://github.com/CAMI-challenge/CAMISIM.git && \
pip3 install numpy ete3 biom-format biopython matplotlib joblib scikit-learn
ENV PATH="/CAMISIM:${PATH}"
Trying WORKDIR as suggested instead of the PATH yielded an error.

Python docker container shuts down immediately after finishing running the app, even if specified to stay in -d -t

I have a dockerfile
FROM python:3
WORKDIR /app
ADD ./venv ./venv
ADD ./data/file1.csv.gz ./data/file1.csv.gz
ADD ./data/file2.csv.gz ./data/file2.csv.gz
ADD ./requirements.txt ./venv/requirements.txt
WORKDIR /app/venv
RUN pip install --no-cache-dir -r requirements.txt
CMD ["python", "./src/script.py", "/app/data/file1.csv.gz", "/app/data/file2.csv.gz"]
After building an image from it and running it, the image runs the app as it should, but then the container shuts down immediately after finishing. This is definitely problematic since I can't expect the output file.
I have tried using docker run -d -t <imgname> and docker ps shows the app for a few seconds, but once again, as soon as it finishes the process, the container shuts itself down.
So it's impossible to access, even with docker exec <imgid> -it --entrypoint /bin/bash, it just immediately exits.
I've also tried adding a last RUN /bin/bash after the last CMD but it doesn't help either.
What can I do actually be able to log into the container and inspect the file?
As long as the container hasen't been removed, you will be able to get at the data. You can find the name of the container using docker ps -a.
Then, if you know the location of the file, you can copy it to your host using
docker cp <container name>:<file> .
Alternatively, you can commit the contents of the container to a new image and run a shell in that using
docker commit <container name> newimagename
docker run --rm -it newimagename /bin/bash
Then you can look around in the container and find your files.
Unfortunately there's no way to start the container up again and look around in it. docker start will start the container, but will run the same command again as was run when you did docker run.

container: volume dockerfile does not work

I m not able to launch new jupyter-notebook from my project.
Below my dockerfile.
FROM python:3.9.0
ARG WORK_DIR=/opt/dir1
RUN apt-get update && apt-get install cron -y && apt-get install -y default-jre
# Install python libraries
COPY requirements.txt /tmp/requirements.txt
RUN pip install --upgrade pip && pip install -r /tmp/requirements.txt
WORKDIR $WORK_DIR
EXPOSE 8888
# Copy etl code
# copy code on container under your workdir "/opt/dir1"
COPY . .
ENTRYPOINT ["sh", "-c"]
CMD ["jupyter-notebook --ip 0.0.0.0 --no-browser --allow-root]
VOLUME /home/data/dir1/
then in my terminal i did
#build
docker build -t my-python-app .
#run
docker run -it -p 8888:8888 my-python-app
#in container i did
jupyter notebook --ip 0.0.0.0 --no-browser --allow-root
I think that my VOLUME doesn't work because when i did modifications in file of container nothing happens in the host /home/data/dir1/.
Does anyone knows why and how to solve it?
You can use, docker run -it /bin/bash (image name)
and try to navigate to the folder you have set the volume to, and see if an error occurs and check permissions.
When using volumes, check on the host system you can access the folder. Afterwards check which user you are, Docker allows to parse your USER_ID and GROUP_ID to the container.
From there you can use the same user and group as you are on the host system. If you wanted to access the same folder on the host system, you can enter into permissions problems.
More information on this on the following webpage.
https://jtreminio.com/blog/running-docker-containers-as-current-host-user/
Maybe it's could be help you : try another way to start the volume inside container, for example add it within "run" command container creation. i've working with docker and i've never added volumes in this way (this doesn't mean you way is wrong)
Here two examples to working with volumens,I recommend you second link.
docker official docs , working with volumes example

running two separate Python-Flask api via a single docker file

I want to run two different python api files running on different ports via a single container.
My docker file looks like:
FROM python:3.7-slim-buster
RUN apt-get update && apt-get install -y libgtk2.0-dev cmake libpoppler-cpp-dev poppler-utils tesseract-ocr
WORKDIR /app
COPY requirements.txt ./
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
RUN chmod a+x run.sh
CMD ["./run.sh"]
And the .sh file looks like:
#!/bin/bash
exec python3 /app1/numberToWord.py &
exec python3 /app2/dollarToGbp.py &
While the docker build is a success without any error, the docker run doesn't throw any error and exits the command line. I'm curios to know where is it failing, any insight is highly appreciated.
Try using nohup to ignore hangup signal
Ex:
#!/bin/bash
nohup python3 /app1/numberToWord.py &
nohup python3 /app2/dollarToGbp.py &
When you run a container, you can specify the specific command to run. You can run two containers, from the same image, with different commands:
docker run -p 8000:8000 --name spelling -d image /app1/numberToWord.py
docker run -p 8001:8000 --name currency -d image /app2/dollarToGbp.py
The important points here are that each container runs a single process, in the foreground.
If your main command script makes it to the end and exits, the container will exit too. The script you show only launches background processes and then completes, and when it completes the container will exit. There needs to be some foreground process to keep the container running, and the easiest way to do this is to just launch the main server you need to run as the only process in the container.

What should I put for Docker CMD and ENTRYPOINT for Flask app running "python myapp.py images/*"

I am trying to run a Flask app using Docker.
Normally, to execute the Flask app, I run this inside of my Terminal:
python myapp.py images/*
I am unsure of how to convert that to Docker CMD syntax (or if I need to edit ENTRYPOINT).
Here is my docker file:
RUN apt-get update -y
RUN apt-get install -y python-pip python-dev build-essential hdf5-tools
COPY . ~/myapp/
WORKDIR ~/myapp/
RUN pip install -r requirements.txt
ENTRYPOINT ["python"]
CMD ["myapp.py"]
Inside of requirements.txt:
flask
numpy
h5py
tensorflow
keras
When I run the docker image:
person#person:~/Projects/$ docker run -d -p 5001:5000 myapp
19645b69b68284255940467ffe81adf0e32a8027f3a8d882b7c024a10e60de46
docker ps:
Up 24 seconds 0.0.0.0:5001->5000/tcp hardcore_edison
When I got to localhost:5001 I get no response.
Is it an issue with my CMD parameter?
EDIT:
New Dockerfile:
RUN apt-get update -y
RUN apt-get install -y python-pip python-dev build-essential hdf5-tools
COPY . ~/myapp/
WORKDIR ~/myapp/
EXPOSE 5000
RUN pip install -r requirements.txt
CMD ["python myapp.py images/*.jpg "]
With this new configuration, when I run:
docker run -d -p 5001:5000 myapp
I get:
docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"python myapp.py images/*.jpg \": stat python myapp.py images/*.jpg : no such file or directory": unknown.
When I run:
docker run -d -p 5001:5000 myapp python myapp.py images/*.jpg
I get the Docker image to run, but now when I go to localhost:5001, it complains that the connection was reset.
I'm glad you've already solved this issue. I put up this answer just for those who still have the same confusions like you do about ENTRYPOINT and CMD executives.
In a Dockerfile, ENTRYPOINT and CMD are two similar executives, but still have strong difference between them. The most important one(only seems to me) is that CMD could be overwritten but ENTRYPOINT not.
To explain this, I may offer you guys the command blow:
docker run -tid --name=container_name image_name [command]
As we can see, command is optional, and it(if exists) could overwrite CMD defined in Dockerfile.
Let's back to your issue. You may have two ways to achieve your purpose-->
ENTRYPOINT ["python"] and CMD ["/path/to/myapp.py", "/path/to/images/*.jpg"].
CMD python /path/to/myapp.py /path/to/images/*.jpg. This is mentioned by #David Maze above.
To understand the first one, you may take CMD as arguments for ENTRYPOINT.
A simple example below.
Dockerfile-->
FROM ubuntu:18.04
ENTRYPOINT ["cat"]
CMD ["/etc/hosts"]
Build image named test-cmd-show and start a container from it.
docker run test-cmd-show
This would show the content in /etc/hosts file. And go on...
docker run test-cmd-show /etc/resolv.conf
And this would show us the content of /etc/resolv.conf file. And go on ...
docker run test-cmd-show --help
This would show the help information for command cat.
Fantastic, right?
Somehow, we could do more research though this functionality.
Add a relevant question: What's the difference between CMD and ENTRYPOINT?
The important thing is that you need a shell to expand your command line, so I’d write
CMD python myapp.py images/*
When you just write CMD like this (without the not-really-JSON brackets and quotes) Docker will implicitly feed the command line through a shell for you.
(You also might consider changing your application to support taking a directory name as configuration in some form and “baking it in” to your application, if these images will be in a fixed place in the container filesystem.)
I would only set ENTRYPOINT when (a) you are setting it to a wrapper shell script that does some first-time setup and then exec "$#"; or (b) when you have a FROM scratch image with a static binary and you literally cannot do anything with the container besides run the one binary in it.
One issue I found was that the app wasn't accessible to Docker. I added this to app.run:
host='0.0.0.0'
According to this:
Deploying a minimal flask app in docker - server connection issues
Next, Docker panics when you add a directory to the CMD parameters.
So, I removed ENTRYPOINT and CMD and manually added the command to the Docker run:
docker docker run -d -p 5001:5000 myappdocker python myapp.py images/*.jpg

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