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Copying files from host to Docker container


Question

I am trying to build a backup and restore solution for the Docker containers that we work with.

I have Docker base image that I have created, ubuntu:base, and do not want have to rebuild it each time with a Docker file to add files to it.

I want to create a script that runs from the host machine and creates a new container using the ubuntu:base Docker image and then copies files into that container.

How can I copy files from the host to the container?

2018/10/22
1
1649
10/22/2018 12:18:23 PM

Accepted Answer

The cp command can be used to copy files.

One specific file can be copied TO the container like:

docker cp foo.txt mycontainer:/foo.txt

One specific file can be copied FROM the container like:

docker cp mycontainer:/foo.txt foo.txt

For emphasis, mycontainer is a container ID, not an image ID.

Multiple files contained by the folder src can be copied into the target folder using:

docker cp src/. mycontainer:/target
docker cp mycontainer:/src/. target

Reference: Docker CLI docs for cp

In Docker versions prior to 1.8 it was only possible to copy files from a container to the host. Not from the host to a container.

2019/08/19
2820
8/19/2019 8:25:29 AM

  1. Get container name or short container id:

    $ docker ps
    
  2. Get full container id:

    $ docker inspect -f   '{{.Id}}'  SHORT_CONTAINER_ID-or-CONTAINER_NAME
    
  3. Copy file:

    $ sudo cp path-file-host /var/lib/docker/aufs/mnt/FULL_CONTAINER_ID/PATH-NEW-FILE
    

EXAMPLE:

$ docker ps

CONTAINER ID      IMAGE    COMMAND       CREATED      STATUS       PORTS        NAMES

d8e703d7e303   solidleon/ssh:latest      /usr/sbin/sshd -D                      cranky_pare

$ docker inspect -f   '{{.Id}}' cranky_pare

or

$ docker inspect -f   '{{.Id}}' d8e703d7e303

d8e703d7e3039a6df6d01bd7fb58d1882e592a85059eb16c4b83cf91847f88e5

$ sudo cp file.txt /var/lib/docker/aufs/mnt/**d8e703d7e3039a6df6d01bd7fb58d1882e592a85059eb16c4b83cf91847f88e5**/root/file.txt
2017/03/11

The cleanest way is to mount a host directory on the container when starting the container:

{host} docker run -v /path/to/hostdir:/mnt --name my_container my_image
{host} docker exec -it my_container bash
{container} cp /mnt/sourcefile /path/to/destfile
2018/09/05

The following is a fairly ugly way of doing it but it works.

docker run -i ubuntu /bin/bash -c 'cat > file' < file
2014/06/11

If you need to do this on a running container you can use docker exec (added in 1.3).

First, find the container's name or ID:

$ docker ps
CONTAINER ID        IMAGE                        COMMAND             CREATED             STATUS              PORTS                   NAMES
b9b7400ddd8f        ubuntu:latest                "/bin/bash"         2 seconds ago       Up 2 seconds                                elated_hodgkin

In the example above we can either use b9b7400ddd8f or elated_hodgkin.

If you wanted to copy everything in /tmp/somefiles on the host to /var/www in the container:

$ cd /tmp/somefiles
$ tar -cv * | docker exec -i elated_hodgkin tar x -C /var/www

We can then exec /bin/bash in the container and verify it worked:

$ docker exec -it elated_hodgkin /bin/bash
[email protected]:/# ls /var/www
file1  file2
2015/01/24

  1. Create a new dockerfile and use the existing image as your base.

    FROM myName/myImage:latest
    
    ADD myFile.py bin/myFile.py
    
  2. Then build the container:

    docker build .
    
2019/09/16