docker build network error when trying to pip install

Question

I am building my first docker install as part of learning django. I have my docker install working. docker info is ok. and hello-world says successfull. But when I run the Dockerfile suggested by the turorial in my Django 3.0 Pro Book by Will Vincent. I get what look like a network dns error.

################ Error:

    Step 6/7 : RUN pip install pipenv && pipenv install --system
 ---> Running in 585e5020f53a
    WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f339144df10>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/pipenv/
   
 WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f3391f05a90>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/pipenv/
   
    WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f3391f05e90>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/pipenv/
    
    WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f3391f05ad0>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/pipenv/
    
    WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f33915ddd90>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution')': /simple/pipenv/
    
    ERROR: Could not find a version that satisfies the requirement pipenv (from versions: none)
    
    ERROR: No matching distribution found for pipenv
The command '/bin/sh -c pip install pipenv && pipenv install --system' returned a non-zero code: 1

####################

Dockerfile try to build:

Pull base image

FROM python:3.7

# Set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

# Set work directory
WORKDIR /code

# Install dependencies
COPY Pipfile Pipfile.lock /code/
RUN pip install pipenv && pipenv install --system

# Copy project
COPY . /code/

It is failing on the RUN pip install.... line.

I have added dns nameserver entries directly into my /etc/resolver.conf file as other have suggested in my search here. not worked.

I assume there is some issue within Docker trying to run pip in the container? This is my first Docker install so exhausted search for answer.

On OS version Centos8

Thanks bill sanderson

Answer 1

Ok, we can try a couple of things. First thing I would do:

• In the Dockerfile add this(with google's dns):

RUN echo "nameserver 8.8.8.8" > /etc/resolv.conf && pip install pipenv && pipenv install --system

It is important to do in the same RUN command.

• Another option is:

docker build --network=host -t yourimage:yourversion .