Docker: unable to prepare context: unable to evaluate symlinks in Dockerfile path: GetFileAttributesEx

kalyani chaudhari

while executing following command:

docker build -t docker-whale .

check that Dockerfile is present in your current working directory.

If you are working on windows 8 you would be using Docker toolbox. From the mydockerbuild directory run the below command as your Dockerfile is a textfile

docker build -t docker-whale -f ./Dockerfile.txt .

The name of the file should be Dockerfile and not .Dockerfile. The file should not have any extension.

satya

Just Remove the extension .txt from Dockerfile and run the command

docker build -t image-name 

It will work for sure.

I had named my file dockerfile instead of Dockerfile (capitalized), and once I changed that, it started processing my "Dockerfile".

I have got this error (in MacBook) though I used correct command to create image,

docker build -t testimg .

Later I found that path is the problem. Just navigate to the correct path that contains docker file. Just double check your current working directory .Nothing to panic!

I had created my DockerFile by VS2017 Docker Support tool and had the same error. After a while I realised I was not in the correct directory that contains the Dockerfile (~\source\repos\DockerWebApplication\). cd'ed to the correct file (~/source/repos/DockerWebApplication/DockerWebApplication) which was inside the project and successfully created the docker image.

In windows 10... period is first parameter

docker build . -t docker-whale

That's just because Notepad add ".txt" at the end of Dockerfile

In WSL, there seems to be a problem with path conversion. The location of the Dockerfile in Ubuntu (where I'm running docker and where Dockerfile lives) is "/home/sxw455/App1", but neither of these commands worked:

$ pwd
/home/sxw455/App1
$ ll
total 4
drwxrwxrwx 0 sxw455 sxw455 4096 Dec 11 19:28 ./
drwxr-xr-x 0 sxw455 sxw455 4096 Dec 11 19:25 ../
-rwxrwxrwx 1 sxw455 sxw455  531 Dec 11 19:26 Dockerfile*
-rwxrwxrwx 1 sxw455 sxw455  666 Dec 11 19:28 app.py*
-rwxrwxrwx 1 sxw455 sxw455   12 Dec 11 19:27 requirements.txt*

$ docker build -t friendlyhello .
unable to prepare context: unable to evaluate symlinks in Dockerfile path: GetFileAttributesEx C:\Windows\System32\Dockerfile: The system cannot find the file specified.

$ docker build -t friendlyhello "/home/sxw455/App1"
unable to prepare context: path "/home/sxw455/App1" not found

But in Windows, the actual path is:

C:\Users\sxw455\AppData\Local\Packages\CanonicalGroupLimited.Ubuntu18.04onWindows_79rhkp1fndgsc\LocalState\rootfs\home\sxw455\App1

And so I had to do this (even though I ran it from bash):

$ docker build -t friendlyhello 
"C:\Users\sxw455\AppData\Local\Packages\CanonicalGroupLimited.Ubuntu18.04onWindows_79rhkp1fndgsc\LocalState\rootfs\home\sxw455\App1"

Sending build context to Docker daemon   5.12kB
Step 1/7 : FROM python:2.7-slim
 ---> 0dc3d8d47241
Step 2/7 : WORKDIR /app
 ---> Using cache
 ---> f739aa02ce04
Step 3/7 : COPY . /app
 ---> Using cache
 ---> 88686c524ae9
Step 4/7 : RUN pip install --trusted-host pypi.python.org -r requirements.txt
 ---> Using cache
 ---> b95f02b14f78
Step 5/7 : EXPOSE 80
 ---> Using cache
 ---> 0924dbc3f695
Step 6/7 : ENV NAME World
 ---> Using cache
 ---> 85c145785b87
Step 7/7 : CMD ["python", "app.py"]
 ---> Using cache
 ---> c2e43b7f0d4a
Successfully built c2e43b7f0d4a
Successfully tagged friendlyhello:latest
SECURITY WARNING: You are building a Docker image from Windows against a non-Windows Docker host. All files and directories added to build context will have '-rwxr-xr-x' permissions. It is recommended to double check and reset permissions for sensitive files and directories.

I had similar problems with environment variables during the initial installation, and followed some advice that said to install the Windows DockerCE and hack the environment variables rather than installing the Ubuntu DockerCE, because (I hope I remembered this correctly) that WSL does not fully implement systemctl. Once the Windows Docker CE installation is done and environment variables are set, docker then works fine under WSL/Ubuntu.

I had originally created my Dockerfile in PowerShell and though I didn't see an extension on the file it showed as a PS File Type...once I created the file from Notepad++ being sure to select the "All types (.)" File Type with no extension on the File Name (Dockerfile). That allowed my image build command to complete successfully....Just make sure your Dockerfile has a Type of "File"...

The problem is that the file name should be Dockerfile and not DockerFile or dockerfile it should be D capital followed by ockerfile in lower-case pls note

niteshkumarmodi

To build Dockerfile save automated content in Dockerfile. not Dockerfile because while opening a file command:

$ notepad Dockerfile 

(A text file is written so file cannot build)

To build file run:

$ notepad Dockerfile

and Now run:

$ docker build -t docker-whale .

Make sure you are in current directory of Dockerfile.

Most importantly make sure your file name is Dockerfile if you use another name it won't work(at least it did not for me.)

Also if you are in the same dir where the Dockerfile is use a . i.e. docker build -t Myubuntu1:v1 . or use the absolute path i.e docker build -t Myubuntu1:v1 /Users/<username>/Desktop/Docker

I my case (run from Windows 10)
1) Rename the file myDockerFile.Dockerfile to Dockerfile (without file extension).
Then run from outside the folder this command:

docker build .\Docker-LocalNifi\ 

This is working for me and for my colleagues at work, hope that will also work for you

Make sure file name "Dockerfile" is not saved with any extension. Just create a file without any extension.

And make sure Dockerfile is in same directory from where you are trying to building docker image.

I got this on Windows when the path I was working in was under a Junction directory. So my fix was to not work under that path.

On Mac it works for below command. (hope your .Dockerfile is in your root directory).

docker build -t docker-whale -f .Dockerfile .

The issue is related to the DockerFile creation procedure.

In order to work, open cmd, cd to the directory of interest and type:

abc>DockerFile

This will create a file called DockerFile inside your folder.

Now type:

notepad DockerFile 

This will open the DockerFile file in notepad and you will have to copy/paste the standard code provided.

Save the file and now, finally, build your image with Docker typing:

docker build -t docker-whale . 

This is working for me and I hope it helps others

Below command worked for me docker build -t docker-whale -f Dockerfile.txt .

Sudharsan S

I tried this and it worked:

$ docker build -t test_dotnet_image 
"C:\Users\ssundarababu\Documents\Docker\Learn\SimpleDockerfile"

Please see quotes+un-quotes around the foldername.

Note: In Folder "C:\Users\ssundarababu\Documents\Docker\Learn\SimpleDockerfile" I have my Dockerfile.