CODEWITHSUNDEEP
dockerdockerfile
Dean Howell
Dean Howell

Reputation: 101

How can I use VOLUME in a Dockerfile to persist individual files in a directory?

This application I'm trying to Dockerize has configuration files in the root of the install dir. If I use VOLUME to mount the install dir on the host, I'll end up with the application on the host, too. I only want to store the configuration files on the host.

Should I use hard links in the container and use VOLUME to mount the dir that has the hardlinks? Do hard links even work in a container?

Upvotes: 0

Views: 353

Answers (1)

Xiongbing Jin
Xiongbing Jin

Reputation: 12087

You can mount individual files. Below is from the docker documentation https://docs.docker.com/engine/userguide/containers/dockervolumes/

Mount a host file as a data volume

The -v flag can also be used to mount a single file - instead of just directories - from the host machine.

$ docker run --rm -it -v ~/.bash_history:/root/.bash_history ubuntu /bin/bash

This will drop you into a bash shell in a new container, you will have your bash history from the host and when you exit the container, the host will have the history of the commands typed while in the container.

Note: Many tools used to edit files including vi and sed --in-place may result in an inode change. Since Docker v1.1.0, this will produce an error such as “sed: cannot rename ./sedKdJ9Dy: Device or resource busy”. In the case where you want to edit the mounted file, it is often easiest to instead mount the parent directory.

Upvotes: 2

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