I have a VirtualBox Guest OS running Ubuntu Server 17.04 which has docker-ce installed.
I have some shared folders that are mounted inside the Guest OS but when I pass them to the docker container with a --volume command I can't see any content inside them. Am I doing something wrong here?
sudo docker create --name=plex -v /home/kunal/media/:/media plexinc/pms-docker
I've seen an issue before (it may have since been fixed) where docker detects all the mounted filesystems on the host when the daemon starts. If you changed mounted filesystems after starting the daemon, it wouldn't see those filesystems for volume mounts. The workaround is to just bounce the docker daemon (e.g. sudo systemctl restart docker) after making any filesystem changes. You may also want to try newer versions of docker to see if the issue has since been fixed.
Related
I have a directory /home/foo/mydir owned by foo:foo (uid=1040) that I bind mount in the alpine docker image as such:
docker run -it --rm -v /home/foo/mydir:/tmp/mydir --user 1040 alpine
but when I check the directory in the container, it is owned by root:root. Am I crazy? I thought docker passed through file ownership when mounting in a container? Is there anyway to retain the permissions (ie have mydir owned by foo:foo in the container) without chown'ing it in the container?
I have two Ubuntu Jammy machines and this issues happened on one machine, but not the other. I finally found the cause and the solution.
Apparently the issue is caused by Docker Desktop. On the first machine I only installed the Docker engine. The second machine had Docker Desktop installed, which runs a virtual machine and your containers will run inside that virtual machine. In that case you can't just mount the host directory the same way into the containers, because you need to mount it first into the virtual machine.
So the solution was simply to remove Docker completely, and then only install the Docker engine (https://docs.docker.com/engine/install/).
Based on my support enquiry here:
https://forums.docker.com/t/bind-mount-permissions-unexpected-mounting-as-root-root/129328?u=swpppp
Say I have a virtual box virtual machine provisioned through Vagrant. I then provision it with docker-machine - so far all good: I can docker-machine ssh into the box and list it ok with docker-machine ls.
In the past, when not yet using dokcer-machine, my usual workflow would involve sshing into the virtual box, installing docker and spinning up my containers.
As far as I understand this is not longer needed as I can control docker containers within the virtual box through docker-machine (and docker itself) from outside the virtual box (essentially from my win dev machine).
Question: how can I mount directories from inside the vm into the container when I am running the docker command from outside the container?
Example to further clarify:
1) old approach. ssh into vbox and run
docker run -i -t --net=try-net \
--name XXXX \
-v ${PWD}/xxxx/yyyy.py:/zzzzz/xxxx/yyyy.py \
-d me/image
2) docker-machine approach. I switch the docker-machine env onto the box. Now how do I reference a folder in the vbox from outside the box? Is this even possible?
From my win host in a Linux like shell:
docker run -v /c/x/y/z:/home --name postgres3 -d postgres:9.5
gets me:
c:\Program Files\Docker\Docker\Resources\bin\docker.exe: Error response from daemon: Invalid bind mount spec "c:\x\y\z\;C:\Program Files (x86)\Git\home": invalid mode: \Program Files (x86)\Git\home.
If you spin up containers using a docker-toolbox install, the VM's are pre-configured to share the /Users folder from the host into the VM which can then be used by containers.
Since you're doing this manually with your own Vagrant install, you'll need to share the folders yourself. This question should walk you through the steps to share a folder from the parent OS into the VM which can be used by Docker containers you spin up with docker-machine.
Edit: with the parent OS synced the the VM, any containers you run inside the VM will just mount volumes there. Docker-machine isn't really a factor, it's just pointing the docker CLI to the selected docker host. The docker CLI would look like:
docker run -v /path/on/vm:/path/in/container image
I have set up Docker for Windows (Hyperv Beta) on my Laptop.
My intention is to laborate on some setups for containers I intend to install in my real server later. I am fairly new to Docker (but know the basics) so I wanted to laborate with volumes and volume images a bit.
However all anonymous volumes end up on the virtual Linux host. I would like to access the filesystem of the host, not within a container.
I cannot access it from within a container easily due to (well founded) security constraints. Neither can I find a way to access it from the windows prompt.
(Using Docker for Windows version 1.12.0-beta21)
I know that it possible to mount volumes using the c share made by Docker for Windows, but that raises the complexity for me. My intent is to use Docker tutorials unmodified and inspect the results in the host filesystem. Preferably through a (bash) shell in the host VM or with a windows file access into the virtual machine.
Later on I would also like to copy volume contents into the vm volumes although that could be solved using a volume against the c drive.
I have after research on my own deducted the following technique to create a privileged container that works as if it was the Linux root host. This is the best I have been able to pinpoint so far.
docker run --net=host --ipc=host --uts=host --pid=host -it --security-opt=seccomp=unconfined --privileged --rm -v /:/host alpine /bin/sh
Docker-machine will allow you to ssh to the default machine by typing:
"docker-machine ssh"
You'll be logged into the VM that is running docker.
I am using docker toolbox on Mac. The setup looks like:
docker host - Boot2Docker VirtualBox VM running on Mac
docker client - Mac
I am using following command - docker run -it -v $PWD/dir_on_docker_client:/dir_inside_container ubuntu:14.04 /bin/bash to run a container with a volume mount. I wonder, how is docker able to mount volume from docker client (in this case Mac) into a docker container running on docker host (in this case, VM running on Mac)?
The toolbox VM includes a shared directory from the client. /c/Users (C:\Users) on Windows and /Users on Mac.
Directories in these folders, on the client, can be added as volumes in a container.
Note though that if you add for example /tmp as a volume, it will be /tmp in the toolbox.
The main problem is that virtulbox shares only your home folder with the docker machine at the moment you can only shares content inside this directory. It's uncomfortable but the unique way that I fund to resolve this problem is with the bootlocal.sh file, you can write this file inside your docker-machine to mount after the boot new directory
https://github.com/boot2docker/boot2docker/blob/master/doc/FAQ.md#local-customisation-with-persistent-partition
Yesterday during this dockercon they announced a public beta for "Docker For Mac", I think that you can replace docker-machine with this tool, it provide the best experience with docker and macos, and it resolves this problem
https://www.docker.com/products/docker
There is possibility to install docker in docker container.
How to control docker host service from it's container (manage another containers)?
If execute docker run --privileged=true -v /var/run/docker.sock:/var/run/docker.sock -v $(which docker):$(which docker) -ti debian and enter docker error appears:
docker: error while loading shared libraries: libapparmor.so.1: cannot open shared object file: No such file
The error you're seeing seems very clear: the docker binary requires a shared library that is not present inside the container.
Is your container running the same distribution and version as your host? If it is, you simply need to determine which packages provide the necessary dependencies and install them inside the container.
If not, you will probably have better luck simply installing docker inside the container, rather than trying to bind-mount it from the host. There is probably a source of recent Docker versions available for Debian.
if your host is a linux based machine, you dont need to install docker inside container, you can just mount docker into container and whatever you do with that inside your container is just like doing it on host. I have tested it on a Ubuntu machine (image: https://github.com/mohamnag/ubuntu-git.git) by mounting /usr/bin/docker from host into /bin/docker inside container. then inside that container you can literally do (build, stop, list ...) whatever you may have done with docker inside host.