How can I add a volume to an existing Docker container

Question

I have a Docker container that I ve created simply by installing Docker on Ubuntu and doing  sudo docker run -i -t ubuntu  bin bash  I immediately started installing Java and some other tools  spent some time with it  and stopped the container by exit  Then I wanted to add a volume and realised that this is not as straightforward as I thought it would be  If I use sudo docker -v  somedir run     then I end up with a fresh new container  so I d have to install Java and do what I ve already done before just to arrive at a container with a mounted volume  All the documentation about mounting a folder from the host seems to imply that mounting a volume is something that can be done when creating a container  So the only option I have to avoid reconfiguring a new container from scratch is to commit the existing container to a repository and use that as the basis of a new one whilst mounting the volume  Is this indeed the only way to add a volume to an existing container

User · Answer

We don t have any way to add volume in running container  but to achieve this objective you may use the below commands  Copy files folders between a container and the local filesystem  docker cp  OPTIONS  CONTAINER SRC PATH DEST PATH  docker cp  OPTIONS  SRC PATH CONTAINER DEST PATH  For reference see  https   docs docker com engine reference commandline cp

User · Answer

A note for using Docker Windows containers after I had to look for this problem for a long time   Condiditions    Windows 10  Docker Desktop  latest version  using Docker Windows Container for image microsoft mssql-server-windows-developer   Problem    I wanted to mount a host dictionary into my windows container    Solution as partially discripted here    create docker container   docker run -d -p 1433 1433 -e sa password  lt STRONG PASSWORD gt  -e ACCEPT EULA Y microsoft mssql-server-windows-developer   go to command shell in container   docker exec -it  lt CONTAINERID gt  cmd exe   create DIR   mkdir DirForMount   stop container   docker container stop  lt CONTAINERID gt    commit container   docker commit  lt CONTAINERID gt   lt NEWIMAGENAME gt    delete old container   docker container rm  lt CONTAINERID gt    create new container with new image and volume mounting   docker run -d -p 1433 1433 -e sa password  lt STRONG PASSWORD gt  -e ACCEPT EULA Y -v C  DirToMount C  DirForMount  lt NEWIMAGENAME gt   After this i solved this problem on docker windows containers

User · Answer

The best way is to copy all the files and folders inside a directory on your local file system by  docker cp  OPTIONS  CONTAINER SRC PATH DEST PATH  SRC PATH is on container DEST PATH is on localhost  Then do docker-compose down attach a volume to the same DEST PATH and run Docker containers by using docker-compose up -d  Add volume by following in docker-compose yml  volumes   - DEST PATH SRC PATH

User · Answer

Unfortunately the switch option to mount a volume is only found in the run command   docker run --help  -v  --volume    list Bind mount a volume  default      There is a way you can work around this though so you won t have to reinstall the applications you ve already set up on your container    Export your container docker container export -o   myimage docker mycontainer Import as an image docker import   myimage docker myimage Then docker run -i -t -v  somedir --name mycontainer myimage  bin bash

User · Answer

I ve successfully mount  home  lt user-name gt  folder of my host to the  mnt folder of the existing  not running  container  You can do it in the following way    Open configuration file corresponding to the stopped container  which can be found at  var lib docker containers 99d   1fb config v2 json  may be config json for older versions of docker   Find MountPoints section  which was empty in my case   MountPoints      Next replace the contents with something like this  you can copy proper contents from another container with proper settings       MountPoints     mnt    Source    home  lt user-name gt    Destination    mnt   RW  true  Name      Driver      Type   bind   Propagation   rprivate   Spec    Type   bind   Source    home  lt user-name gt    Target    mnt    SkipMountpointCreation  false     or the same  formatted       MountPoints           mnt            Source     home  lt user-name gt           Destination     mnt          RW   true         Name              Driver              Type    bind          Propagation    rprivate          Spec              Type    bind            Source     home  lt user-name gt             Target     mnt                  SkipMountpointCreation   false              Restart the docker service  service docker restart   This works for me with Ubuntu 18 04 1 and Docker 18 09 0

User · Answer

You can commit your existing container  that is create a new image from container   s changes  and then run it with your new mounts  Example    docker ps  -a CONTAINER ID        IMAGE                 COMMAND                  CREATED              STATUS                          PORTS               NAMES     5a8f89adeead        ubuntu 14 04           quot  bin bash quot               About a minute ago   Exited  0  About a minute ago                       agitated newton    docker commit 5a8f89adeead newimagename    docker run -ti -v  quot  PWD somedir quot   somedir newimagename  bin bash  If it s all OK  stop your old container  and use this new one  That  s it

User · Answer

J  r  me Petazzoni has a pretty interesting blog post on how to Attach a volume to a container while it is running  This isn t something that s built into Docker out of the box  but possible to accomplish  As he also points out  This will not work on filesystems which are not based on block devices  It will only work if  proc mounts correctly lists the block device node  which  as we saw above  is not necessarily true   Also  I only tested this on my local environment  I didn   t even try on a cloud instance or anything like that  YMMV

[docker] How can I add a volume to an existing Docker container?

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