COPY statement does not actually copy my file

[rimelek (Ákos Takács)]

@juakesson

matlab-server:latest

This name is not mentioned in the documentation you shared. Please, share the Dockerfile that you used to build the base image unless it contains something that you can’t share. Sharing only a documentation would require us to check it, understand it and figure out what you did differently when we might not even know the tool that you are running in the container.

Also to avoid misunderstanding, please, format your codes as described in the bellow post:

How to format your forum posts

The Docker forum is using Discourse, which supports several ways to format your posts: Markdown; see commonmark.org/help for an interactive tutorial BBCode A small selection of HTML Any combination of the above Blank lines for formatting and readability Quite often you’ll need an empty line above specific formatting to make it work. You also need to type blank lines to create proper paragraphs; just pressing Return once and then typing a new block of text right below a previous block only…

@juakesson

However, when I run my container using the following line, I cannot find the files in the container filesystem via the terminal:

docker run --rm -p 9002:9002 matlab-server:new

How do you know that the file is not there? If you can share commands that actually shows what command indicated the file was missing, that can help us a lot to help you faster and ask better questions. Later you mentioned the “ls” command, but we all make mistakes, so the fact that you used “ls” doesn’t guarantee you used it correctly.

@juakesson

Could there be some issue with a .dockerignore

@ajeetraina

If you’re using a .dockerignore file,

@juakesson

I have not explicitly defined a .dockerignore-file

Can I ask why you suspected the reason could have been a dockerignore file when you don’t have one? Only to make sure we understand eachother correctly. Note that the filename would be .dockerignore and not .dockerignore-file or anything like that. If something created a .dockerignore file it is possible that you don’t see it because those files beginning with a dot are hidden by default.

However you also mentioned that

@juakesson

the only files that exist in this folder are the files that i added in the Dockerfile build

which indicates that indeed you don’t have a .dockerignore file or doesn’t match the files that you want to copy.

I also need to ask you to share the output of the following commands as it is very important to know what kind of Docker installation you are using.

docker info
docker version

You could also check if you have any ONBUILD instruction in the Dockerfile of the base image so it runs after your instructions and can remove the copied files.

@juakesson

docker run --rm -p 9002:9002 matlab-server:new

Was this the exact same command that you run? Didn’t you use any mounted folder?

Another reason of missing files could be that a command runs in your entrypoint removing the copied files. To help you with that, again, we need more information how you have built the base image exactly.

By the way, you chose the “Docker Hub” category and the question has nothing to do with Docker Hub, so based on the output of docker info we can move the topic to the correct category.