I was trying to write a Docker log file on Ubuntu 20.04 by
sudo docker logs CONTAINER_ID >output.log
But it returned
-bash: output.log: Permission denied
How to solve the permission problem to save the logs? Is the problem inside the container or outside of it?
P.S. I had this container by docker run -d -v ~/desktop/usercode/Docker:/code -p 5000:5000 flask_app:1.0, and the Dockerfile is as below:
## Base Python Image for App
FROM python:3.9-rc-buster
# Setting up Docker environment
# Setting Work directory for RUN CMD commands
WORKDIR /code
# Export env variables.
ENV FLASK_APP app.py
ENV FLASK_RUN_HOST 0.0.0.0
###
#Copy requirements file from current directory to file in
#containers code directory we have just created.
COPY requirements.txt requirements.txt
#Run and install all required modules in container
RUN pip3 install -r requirements.txt
#Copy current directory files to containers code directory
COPY . .
#RUN app.
CMD ["flask", "run"]
And, the images are:
REPOSITORY TAG IMAGE ID CREATED SIZE
flask_app 1.0 90b2840f4d5d 29 minutes ago 895MB
python 3.9-rc-buster 50625b35cf42 9 months ago 884MB
The command you entered first creates output.log file in the same direction as you are, then drops the logs in that file; It seems that the problem is solved if you use the following command.
docker logs CONTAINER_ID > ~/output.log
This command creates a log file in the root path of the user you are. for example if your username is USER1 that file create at /home/USER1