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Question Detail

I just downloaded Docker Toolbox for Windows 10 64bit today. I’m going through the tutorial. I’m receving the following error when trying to build an image using a Dockerfile.

Steps:

  • Launched Docker Quickstart terminal.
  • testdocker after creating it.
  • Prepare Dockerfile as documented in “Build your own image” web link
  • ran below command

docker build -t docker-whale .

Error: $ docker build -t docker-whale .

unable to prepare context: unable to evaluate symlinks in Dockerfile path: GetFileAttributesEx C:\Users\Villanueva\Test\testdocker\Dockerfile: The system cannot find the file specified.

BTW: I tried several options mentioned @ https://github.com/docker/docker/issues/14339

    $ docker info
    Containers: 4
     Running: 0
     Paused: 0
     Stopped: 4
    Images: 2
    Server Version: 1.10.1
    Storage Driver: aufs
     Root Dir: /mnt/sda1/var/lib/docker/aufs
     Backing Filesystem: extfs
     Dirs: 20
     Dirperm1 Supported: true
    Execution Driver: native-0.2
    Logging Driver: json-file
    Plugins:
     Volume: local
     Network: bridge null host
    Kernel Version: 4.1.17-boot2docker
    Operating System: Boot2Docker 1.10.1 (TCL 6.4.1); master : b03e158 - Thu Feb 11 22:34:01 UTC 2016
    OSType: linux
    Architecture: x86_64
    CPUs: 1
    Total Memory: 996.2 MiB
    Name: default
    ID: C7DS:CIAJ:FTSN:PCGD:ZW25:MQNG:H3HK:KRJL:G6FC:VPRW:SEWW:KP7B
    Debug mode (server): true
     File Descriptors: 32
     Goroutines: 44
     System Time: 2016-02-19T17:37:37.706076803Z
     EventsListeners: 0
     Init SHA1:
     Init Path: /usr/local/bin/docker
     Docker Root Dir: /mnt/sda1/var/lib/docker
    Labels:
     provider=virtualbox

Thanks.

Question Answer

while executing following command:

docker build -t docker-whale .

check that Dockerfile is present in your current working directory.

The error message is misleading. The problem has nothing to do with symlinks really. It is usually only that docker cannot find the Dockerfile describing the build.

Typical reasons are these:

  • Dockerfile has wrong name.
    It must be called Dockerfile. If it is called, for instance, dockerfile, .Dockerfile, Dockerfile.txt, or other, it will not be found.
  • Dockerfile is not in context.
    If you say docker build contextdir, the Dockerfile must be at contextdir/Dockerfile. If you have it in, say, ./Dockerfile instead, it will not be found.
  • Dockerfile does not exist at all.
    Sounds silly? Well, I got the above error message from my GitLab CI after I had written a nice Dockerfile, but forgotten to check it in. Silly? Sure. Unlikely? No.

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.

  1. Make sure you moved to the directory where Dockerfile is located.
  2. Make sure your Dockerfile is extension-less. That is, not Dockerfile.txt, Dockerfile.rtf, or any other.
  3. Make sure you named Dockerfile, and not DockerFile, dockerfile or any other.

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

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

docker build -t image-name 

It will work for sure.

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!

That’s just because Notepad add “.txt” at the end of Dockerfile

This command worked for me:

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

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 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.

Two ways to build a dockerfile:

You can decide not to specify the file name of which to build from and just build it specifying a path (doing it this way the file name must be Dockerfile with no extension appended, eg: docker build -t docker-whale:tag path/to/Dockerfile

or

You can specify a file with -f and it doesn’t matter what extension (within reason .txt, .dockerfile, .Dockerfile etc..) you decide to use, eg docker build -t docker-whale:tag /path/to/file -f docker-whale.dockerfile.

In windows 10, period is first parameter

docker build . -t docker-whale

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

Be sure your DOCKERfile is in the ROOT of the application directory, I had mine in src which resulted in this error because Docker was not finding the path to DOCKERfile

The error means that docker build is either using a PATH | URL that are incorrectly input or that the Dockerfile cannot be found in the current directory. Also, make sure that when running the command from an integrated terminal (e.g. bash inside your IDE or text editor) you have the admin permissions to do so.
Best if you can check the PATH from your terminal with pwd (in bash shell or dir if using a simple cli on windows) and copy the exact path where you want the image to be build.

docker build C:\windows\your_amazing_directory

docker build --help will also show you available options to use in case of malformed or illegal commands.

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.

In case if we have multiple docker files in our environment just Dockerfile wont suffice our requirement.

docker build -t ihub -f Dockerfile.ihub .

So use the file (-f argument) command to specify your docker file(Dockerfile.ihub)

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

I erroneously created Dockerfile.txt in my working directory leading to the above-mentioned error while build

The fix was to remove the .txt extension from the file.

The file name should be Dockerfile only without any extension.

Execute docker build -t getting-started . in your project directory and make sure Dockerfile is present and having no .txt extension.
If you are on Windows, check the ‘file name extension’ in the under the view tab in the
File Explorer to show whether .txt is there or not and remove it if the former is true.
Good Luck.

I also faced the same issues and it was resolved when i created file named with DockerFile and mentioned all the command which wanted to get executed while creation of any image.

If you have mounted a second drive to an NTFS folder as a ‘mounted volume’ then you can get this issue.

Move you files to a drive location outside of the mounted volume.

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