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Introduction of Docker ENTRYPOINT. Docker entrypoint is a Dockerfile directive or instruction that is used to specify the executable which should run when a container is started from a Docker image. It has two forms, the first one is the 'exec' form and the second one is the 'shell' form.
Step 1: Create a script.sh file and copy the following contents. Step 2: You should have the script.sh is the same folder where you have the Dockerfile. Create the Dockerfile with the following contents which copy the script to the container and runs it part of the ENTRYPOINT using the arguments from CMD.
Example of using CMD and ENTRYPOINT togetherIf both ENTRYPOINT and CMD are present, what is written in CMD is executed as an option of the command written in ENTRYPOINT. If an argument is added at the time of docker run , the contents of CMD will be overwritten and the ENTRYPOINT command will be executed.
ENTRYPOINT is the other instruction used to configure how the container will run. Just like with CMD, you need to specify a command and parameters. However, in the case of ENTRYPOINT we cannot override the ENTRYPOINT instruction by adding command-line parameters to the `docker run` command.
I was tearing my hair out with an issue very similar to this. In my case /bin/bash DID exist. But actually the problem was Windows line endings.
In my case the git repository had an entry point script with Unix line endings (\n). But when the repository was checked out on a windows machine, git decided to try and be clever and replace the line endings in the files with windows line endings (\r\n).
This meant that the shebang didn't work because instead of looking for /bin/bash, it was looking for /bin/bash\r.
The solution for me was to disable git's automatic conversion:
git config --global core.autocrlf input
Then check out the repository again and rebuild.
Some more helpful info here: How to change line-ending settings and here http://willi.am/blog/2016/08/11/docker-for-windows-dealing-with-windows-line-endings/
the vault:latest image does not contain /bin/bash which you try to call with your shebang #!/bin/bash. You should either change that to #!/bin/sh or completely remove the shebang from your script.
Without seeing your image, my initial idea is that you don't have /bin/bash in your image. Changing the first line of your docker-entrypoint.sh to:
#!/bin/sh
will likely resolve it.
Another possibility:
Check that the file is not saved with Windows line endings (CRLF). If it is, save it with Unix line endings (LF) and it will be found.
I struggled for hours because I haven't noticed anywhere explained that you need to copy the file in the location where the VM can access the file, preferably globally like so:
COPY docker-entrypoint.sh /usr/local/bin/
(I had thought it should just be automatically accessible since it's part of the dockerfile context)
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