rm: cannot remove '/etc/nginx/conf.d/*': No such file or directory

[IavTavares]

I'm trying to dockerize a flask + gunicorn app with nginx.

Here's the initial part of my dockerfile:

FROM ubuntu
ARG DEBIAN_FRONTEND=noninteractive
ARG DEBCONF_NONINTERACTIVE_SEEN=true
# it seems to be important ARGs related to shell come before any run
RUN apt-get update && apt-get install -y python3 python3-pip ffmpeg libsm6 libxext6
RUN apt-get install -y imagemagick

RUN apt-get install nginx -y

COPY . . 
RUN rm /etc/nginx/conf.d/default.conf

when building the docker image, I get the error message: rm: cannot remove '/etc/nginx/conf.d/default.conf': No such file or directory.

Even if i change the RUN command to RUN rm /etc/nginx/conf.d/*, I still get the same error message. It makes me think that there's no directory with that name.

But isn't it supposed to exit according to the documentation?

[brianehlert]

you might find this blog useful: https://www.nginx.com/blog/deploying-nginx-nginx-plus-docker/
Also, run your container and verify the path. I believe you are expecting a very old path.

[lucacome]

@IavTavares there are a couple of problems:

• you didn't install the necessary dependencies, for example lsb-release so it won't be able to automatically resolve the ubuntu version (you could just replace lsb_release -cs with focal in this case or the version you're using)
• you're actually not adding anything any text to those files because you have a | before the >

FROM ubuntu
ARG DEBIAN_FRONTEND=noninteractive
ARG DEBCONF_NONINTERACTIVE_SEEN=true

RUN apt-get update && apt-get install -y python3 python3-pip ffmpeg libsm6 libxext6
RUN apt install -y curl gnupg2 ca-certificates lsb-release ubuntu-keyring
RUN apt-get install -y imagemagick

RUN curl -fssL https://nginx.org/keys/nginx_signing.key | gpg --dearmor > /usr/share/keyrings/nginx-archive-keyring.gpg

# choosing mainline nginx image
RUN printf "%s\n" "deb [signed-by=/usr/share/keyrings/nginx-archive-keyring.gpg] \
    http://nginx.org/packages/mainline/ubuntu `lsb_release -cs` nginx" > /etc/apt/sources.list.d/nginx.list
RUN printf "%s\n" "Package: *" "Pin: origin nginx.org" "Pin: release o=nginx" \
    "Pin-Priority: 900" > /etc/apt/preferences.d/99nginx
# we need to update apt after this

RUN apt update && apt install nginx -y

COPY . .
RUN rm /etc/nginx/conf.d/*

this is an example of how I changed your Dockerfile (I prefer to use prinft to echo, it's cleaner to me 😄 )

[IavTavares]

@lucacome Hi Luca, thanks for the help! Sorry for the late reply, but life happened... I'll try today your suggestion, and keep you posted. ;)

[IavTavares]

@lucacome
So, Luca, I've tried the following:

RUN apt update && apt install -y python3 python3-pip ffmpeg libsm6 libxext6

RUN apt install -y curl gnupg2 ca-certificates lsb-release ubuntu-keyring

RUN curl -fssL https://nginx.org/keys/nginx_signing.key | gpg --dearmor > /usr/share/keyrings/nginx-archive-keyring.gpg

# choosing stable nginx image
RUN echo "deb [signed-by=/usr/share/keyrings/nginx-archive-keyring.gpg] \
    http://nginx.org/packages/ubuntu focal nginx" > /etc/apt/sources.list.d/nginx.list
RUN echo -e "Package: *\nPin: origin nginx.org\nPin: release o=nginx\nPin-Priority: 900\n" \
    > /etc/apt/preferences.d/99nginx

# we need to update apt after this
RUN apt update && apt install nginx -y

And got the following error message:
E: Invalid record in the preferences file /etc/apt/preferences.d/99nginx, no Package header
I don't seem to find a solution online...

[lucacome]

@IavTavares

it looks like echo -e is the problem as it's printing -e to the file.
Docker uses sh as the default shell when building a Dockerfile (and in most distributions, sh is actually a symlink to ash that has echo as a builtin command and it doesn't support -e), so the implementation is different than for example in bash (I guess the most popular shell).

That's why I prefer to use printf 🙂 but you could also change the shell by adding SHELL ["/bin/bash", "-c"] in your Dockerfile, before the RUN commands

As a side note, usually when I see that a step is not behaving correctly or as I think it should, I just comment out the lines after that (in this case RUN apt-update ... and build the container, then I just run the container and inspect the files to see that everything is in order.

I hope it helps.

[IavTavares]

@lucacome Many thanks for all the help. I've just solved the problem! ;)