I created own Dockerfile, during building I inserted to /opt/wilfly/log my log4j.xml.
Now I need create volume /mnt/data/logs/application:/opt/wildfly/log
I run command
sudo docker run --name=myapp -v /mnt/data/logs/application:/opt/wildfly/log -d -i -t application
But when I look in docker container, folder /opt/wilfly/log is empty. In this folder should by log4j.xml.
Thank you.
Maybe you should move it into another directory.
For example move log4j.xml to /opt/wilfly/ and set logging path to /opt/wilfly/log.
When you run the container, log4j.xml will not disappear.
When you mount the data, the folder from your host "override" your mounted folder within the container.
Thus, there are some options you can do:
copy the log4j.xml into your local /mnt/data/logs/application folder and run the container as you did.
remove the -v /mnt/data/logs/application:/opt/wildfly/log and use the original log4j.xml that you were added during the image build.
Please note that you can also mount only the file if you like (rather than the entire floder): -v /mnt/data/logs/application/log4j.xml:/opt/wildfly/log/log4j.xml but it won't change the behavior - the file from your host will be mounted into the container and not in the opposite direction.
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.
what I want to accomplish
I want to use the functions written in the .vimrc placed on the host side within Docker.
what I did
Put the .vimrc file in the /home/akihiro directory on the host side.
When using the docker run command, mount the /home/akihiro directory on the host side and run the python file in Docker with Vim.
akihiro#akihiro-thinkpad-x1-carbon-5th:~$ docker run --rm -it -v /home/akihiro:/home --name test cnn_study:latest
As a result, the settings written in the .vimrc file did not work.
Next, I started a new container without mounting.
Created /home/akihiro directory in the container.
I left the container.
I copied only the /home/akihiro/.vimrc file on the host side into the container, and re-entered the container.
docker cp ./.vimrc 52b28f1ffea8:/home/akihiro
Started up a Python file using Vim.
As a result, the settings written in the .vimrc file did not work.
What you are doing is mapping the complete /home or /home/akihiro directory on the Container.
You can't do that for 2 reasons:
There are more files in that directory. What do you expect happens with them?
It's not like a OR-function is done on files in both folder.
Mapping the volume complete replaces the internal folder
My gut feeling says that mapping the direcory comes too late in the process.
The directory is already there in the Container and therefore cannot be overwritten.
(At least that's how I understand the strange effects I get with mapping sometimes)
What you should do is only map the file:
$ docker run --rm -it -v /home/akihiro/.vimrc:/home/akihiro/.vimrc --name test cnn_study:latest
I do the same with .bashrc (to set the prompt to the name of the Container)
I want access /etc/php5/apache2 in my container, where f.e. php.ini is located.
As soon as I mount my volume...it seems the container can't write the default php.ini to the apache2 folder, because apache2 folder and config folder on host are empty.
docker config:
./config/:/etc/php5/apache2
I have also tested Z flag without any success. Folder config on host is read/write/excutable by everyone.
A volume shadows data in the container, e.g. if there is bla.txt in the folder in the container, after mounting you won't see the file.
If you only need to see the file, you can go into the the container using docker exec -it <id> /bin/sh and then look into the file.
Alternatively use docker cp to copy the file, but I never needed that.
The use case is that I want to download and image that contains python code files. Assume the image does not have any text editor installed. So i want to mount a drive on host, so that files in the container show up in this host mount and i can use different editors installed on my host to update the code. Saving the changes are to be reflected in the image.
if i run the following >
docker run -v /host/empty/dir:/container/folder/with/code/files -it myimage
the /host/empty/dir is still empty, and browsing the container dir also shows it as empty. What I want is the file contents of /container/folder/with/code/files to show up in /host/empty/dir
Sébastien Helbert answer is correct. But there is still a way to do this in 2 steps.
First run the container to extract the files:
docker run --rm -it myimage
In another terminal, type this command to copy what you want from the container.
docker cp <container_id>:/container/folder/with/code/files /host/empty/dir
Now stop the container. It will be deleted (--rm) when stopped.
Now if you run your original command, it will work as expected.
docker run -v /host/empty/dir:/container/folder/with/code/files -it myimage
There is another way to access the files from within the container without copying it but it's very cumbersome.
Your /host/empty/dir is always empty because the volume binding replaces (overrides) the container folder with your empty host folder. But you can not do the opposite, that is, you take a container folder to replace your host folder.
However, there is a workaround by manually copying the files from your container folder to your host folder. before using them as you have suggested.
For exemple :
run your docker image with a volume maaping between you host folder and a temp folder : docker run -v /host/empty/dir:/some-temp-folder -it myimage
copy your /container/folder/with/code/files content into /some-temp-folder to fill you host folder with you container folder
run you container with a volum mapping on /host/empty/dir but now this folder is no longer empty : run -v /host/empty/dir:/container/folder/with/code/files -it myimage
Note that steps 1 & 2 may be replaced by : Copying files from Docker container to host
I made a docker image called myImage, there is a folder: /data I want to let the user edit it by themselves. I read that -v flag can mount the volume, so I used it like following:
I run the container with this command:
docker run -v /my_local_path:/data -it myImage /bin/bash
But surprisingly, docker cleared all the files in /data in the container. But this is not I want... I want actually the host can get all the files from /data... :(
How can I do that?
When you share a volume like this, the volume on the host overwrites the volume in the container, so the files in the container's folder will be removed.
What you need to do is put the files in the container in folder A (a folder in the container). Mount folder B (another folder in the container). Then AFTER the volume is mounted, move the files from folder A to folder B. Then these files will be both available to the host and inside the container.
You can achieve this 'move files' operation using a RUN or an ENTRYPOINT script in your Dockerfile.
See Run a script in Dockerfile
Sorry, I forget if you need RUN or ENTRYPOINT (or if either will work) but one of these will definitely do it.
I think you want ENTRYPOINT because an ENTRYPOINT script runs AFTER the container is created. Thus it will run after the volume is mounted.