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CompSciGuy139
CompSciGuy139

Reputation: 107

Docker Volumes mounting issue

I am trying to dynamically mount a volume from the container to the host and it works but there is a hitch. I am using the following command:

    docker run -it --name Test1 -v $HOME/.myapp_configs/specificConfig.txt:/bin/specificConfig.txt:rw docker-image /bin/bash

The issue lies in that if the mount point on the host does not exist the docker command creates it but assigns it root:root rather than $USER:$USER like I would expect. I gather that this is more than likely a direct result of the namespace mapping issue that has been identified with Docker.

Does anyone have any thoughts on how I can force the host mount point to be created with the appropriate permissions? i.e.

    drwxr-xr-x. 3 $USER $USER  31 Aug 21 15:02  ~/.myapp_configs/specificConfig.txt

instead of...

    drwxr-xr-x. 3  root  root  31 Aug 21 15:02  ~/.myapp_configs/specificConfig.txt

Thanks,

Bruce

Upvotes: 0

Views: 629

Answers (1)

Thomasleveil
Thomasleveil

Reputation: 103965

What about making sure the file exists before running the container?

the command could look like:

test -f $HOME/.myapp_configs/specificConfig.txt || touch $HOME/.myapp_configs/specificConfig.txt
docker run -it --name Test1 -v $HOME/.myapp_configs/specificConfig.txt:/bin/specificConfig.txt:rw docker-image /bin/bash

explanation:

  • test -f <some file> will have exit status 0 if the file exists
  • || will execute the following command only if the previous command exit status is different than 0
  • touch <some file> modify an existing file modification time, or (and this is our case) create an empty file

Of course, if inside your container lies some code that acts differently whether the file exists or not, then you would have to adapt that code to check if the file is empty instead.

Upvotes: 1

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