Is there a way to share folder from docker container to host?
For example I have tomcat inside docker container and I want it to be visible from the outside.
If I do
volumes:
- /opt/tomcat:/opt/tomcat
I receive an error in the container:
"No such file or directory /opt/tomcat/bin/catalina.sh"
I don't think Docker allows you to that. That command will mount your host folder in the container, so your files in the container are not visible anymore.
Two options:
You can access the container files using this trick (GitHub issue):
sudo ls /proc/$(docker inspect --format {{.State.Pid}} YOUR_CONTAINER_NAME)/root. To access them you will need root privileges, or you can use bindfs to match root user with your user name (see the same thread).
Create a new volume, copy the files you need to be accessible to there and mount it inside the container, in the right place
Related
I have a docker image, and I am running it now (finishing with bash)
When I do, I have a file structure inside the container.
However, this is not some file structure mapped (with -v) from outside the container. These files and folders exist only inside the container.
My question is, since it is bothersome to be opening each file with vi and navigating from the terminal, is there a way that I can open vscode on these files?
Be aware that these files do not exist outside the container
I found how to do it from this link
However I used the "attach to running container" command
I rarely do that but when I have to I usually mount an empty volume to the container, then exec into the container copy the folder which I need into that empty volume, which is then replicated on my host machine. From my host machine I then open it in vscode.
However please be careful if you have sensitive information in that container, not to expose something by accident.
So the steps are:
Create empty volume ( docker-compose example )
Note do not overwrite the folder/file which you want to extract. containerpath is path which does not exist in the container prior to creating it.
volume:
- ./hostpath:/containerpath
Find docker id so that you can use it to exec into it:
docker ps
Exec into the container:
docker exec -it <container_id> /bin/sh
Copy the file/folder to that empty volume:
cp -r folder containerpath
Exit the container and look at your files in ./hostpath folder.
I would like to have a Docker Volume that mounts to a container. This volume would need to be somewhere other than the default location of volumes, preferably somewhere on the Desktop. This is because I am running a web server and would like some directories to be editable by something like VSCode so I don't always have to go inside the container to edit a file. I am not going to be using Docker Compose and instead will be using a Docker File for the container. The functionality I'm going for is the following equivalent of Docker Compose, but in a Dockerfile or through docker run, whichever is easiest to accomplish:
volumes:
- <local-dir>:<container-dir>
This directory will need to be editable LIVE and using the Dockerfile ADD command will not suffice, because after building, the image gets put into a tar archive and cannot be accessed after that.
with this solution you can move even A live container to new partition:
Add a configuration file to tell the docker daemon what is the location of the data directory
Using your preferred text editor add a file named daemon.json under the directory /etc/docker. The file should have this content:
{
"data-root": "/path/to/your/docker"
}
Copy the current data directory to the new one
sudo rsync -aP /var/lib/docker/ /path/to/your/docker
Rename the old docker directory
sudo mv /var/lib/docker /var/lib/docker.old
Restart the docker daemon
sudo service docker start
resource: https://www.guguweb.com/2019/02/07/how-to-move-docker-data-directory-to-another-location-on-ubuntu/
You can mount a directory from your host inside your container when you launch the docker container, using -v or --volume
docker run -v /path/to/desktop/some-dir:/container-dir/path <docker-image>
Volumes specified in the Dockerfile, as you exemplified, will automatically create those volumes under /var/lib/docker/volumes/ every time a container is launched from that image, but it is NOT recommended have these volumes altered by non-Docker processes.
I want to mount a folder of the host system to the container and it need to be defined in the Dockerfile so that user doesn't need to do it manually by passing the argument in the command line to run the container. How to achieve this ?
This simply cannot be done. Docker images are designed to be portable. Host mounts are host specific. Thus if you are able to specify a host mount at build time, it will make the image non-portable across machine that don't have this mount folder. Thus this is why this option is not available.
You can use docker compose to help the user not choose the mount folder. Take a look at How do I mount a host directory as a volume in docker compose
Dockerfile is for create images not containers.
You can not define a volume on a image. The volume must be defined on execution time when the container is created.
docker run -v /host-folder:/root/containerfolder -i -t imagename
How do I access a folder on the Container from host.
I start a container, and lets say I want to see on host the contents of the container's /home.
Without being root and going to the docker overlay file system to see what is there. But of course I am in group docker and can ask docker to make the neccessary actions.
What if I wish to mount the /home of the container to /test on the host?
I want to avoid mounting a host path into the container and copying from there since I dont want to allow the container to write to host, but the host will copy the content by himself.
How could I achieve this?
I'll answer two questions:
2) To see the contents of a directory inside the container, use docker exec command.
Here is an example of how to:
# docker run -it --rm --name test_con ubuntu:16.04 /bin/bash
You can then open a new terminal session and run the command.
# docker exec test_con ls /home
Replace test_con with the name or ID of your container and ls /home with any command you want to be executed on the container without attaching to its console.
3) You can use docker cp command to copy files/folders between a container and the local filesystem. Using above container as an example, you’ll run a command like this:
# docker cp test_con:/home /test
Where /test is a directory on the host system. It will be automatically created if it doesn't exist.
Your question 2 and 4 seem to be duplicate of the other two.
Let's say that I start a docker container with a bind-mounted local folder:
docker run --rm -v /ux1/dmtest:/data -it ubuntu
Then, locally - not inside the container, I bind-mount a directory from another fs into /ux1/dmtest:
mkdir /ux1/dmtest/bm
mount --bind /ux0/bm /ux1/dmtest/bm
Now, from the container, I see /data/bm/ and I can write content to it, but this content will not be visible on the host on /ux0/bm.
Where is this content stored?
And is there any way to mount additional storage into a running docker container (this workaround clearly doesn't work)?
Mounts done after the fact won't be seen by the container due to mount namespaces that Docker uses. The files will be in the /ux1/dmtest directory that was in place before your second bind mount.
If you do want to use a bind mount, put it in place, and then start the docker daemon, and then your container will see it.