I want to rename a conf.dev.json file to conf.json within the image during docker run time. How is this accomplished?
I don't want to rename the file during image build because I don't want to build env specific images and mounting a volume wont really work because I'm serving the file from within nginx server running in the container which is serving the site from the container image's /html directory.
ok it looks like with nginx there is a magic folder that contains scripts to execute when the images starts.
https://stackoverflow.com/a/70575191/491436
I'm going to try this but if there is a more elegant way to approach this please do let me know.
Thanks!
If the file config.dev.json is located in /local on your host and the target file inside the container should be located in /tmp/config.json, then
docker run -v /local/config.dev.json:/tmp/config.json -it -p 8080:8080 yourimage
Related
I am working with Golang application that saves the information inside sqlite file and that resideds inside the data/sqlite.db same directory as docker file. My docker file is something like this
p.s: guys it's my very first docker file please be kind to me :(
FROM golang:1.16.4
ENV GIN_MODE=release
ENV PORT=8081
ADD . /go/src/multisig-svc
WORKDIR /go/src/multisig-svc
RUN go mod download
RUN go build -o bin/multisig-svc cmd/main.go
EXPOSE $PORT
ENTRYPOINT ./bin/multisig-svc
I deployed this application to the Google cloud plateform but somehow the container gets restarted there and after that my db is vanished. So i researched and try to use volumes.
I build the container using this command docker build -t svc . and then run it with docker run -p 8080:8081 -v data:/var/dump -it svc but i can not see the data folder is getting copied to /var/dump directory. My basic idea is , Whenever the container start it loads the db file from dump and then past it to data directory so application can use it and when it exits it copy it back to dump directory. I don't know if i am on right track any help would really be appreciated.
#Edit
The issue is when no request arrives for 15 minutes GPC shut down the container and start it when there comes a request again. Now the issue is to somehow fetch the db file from dump directory update it and write it back to the dump dir when container goes down for future use.
For a local run and if you are running on a VM, you need to specify the absolute path of the directory you want to mount as a bind mount into your directory. In this case something like that should work
docker run -p 8080:8081 -v $(pwd)/data:/var/dump -it svc
When you don't specify the absolute path, the volume you're mounting to your running container is a named volume manage by the docker daemon. And it is not located in a path related to your current working directory. You can find more information about how work docker volumes here https://docs.docker.com/storage/volumes/
However there are multiple environment on GCP (app engine, kubernetes, VMs), so depending on your environment you may need to adapt this solution.
I'm fairly new to using Docker and Docker Compose (using Docker Compose for this particular problem). Here is what I know so far about the problem I am facing: When using volumes when there are contents available in the host folder as well as the container's folder, the files inside the container's folder are hidden and the host's files are then made available to the container.
I want to use it the other way round. I would like to make available the container's files (that were copied into the image in the Dockerfile) to the host folder.
Is there a way to do that?
Here are a bunch of screenshots of my Dockerfile and Docker Compose to show my setup.
Dockerfile Screenshot
DockerCompose Screenshot
Thanks in advance! :)
I've come across the same thing many times and the way I go about it is as follows.
As the host volume will always take priority over the container filesystem, you have to copy the files out of the container to the host first, then volume mount them back - this way you get what was there originally, and also what might change in the future (by the container).
The following is all pseudo code, but should hopefully simulate the concept:
First run the main container:
docker run --rm -d --name my-container registry/image-name
Then copy the files you want from it to the local filesystem
docker cp my-container:/files/i/want ./files
Then stop the original container
docker stop my-container
Then mount them back into the container on the next run
docker run --rm -d --name my-container -v ./files:/files/i/want registry/image-name
Obviously you've mentioned compose there also, so just reflect the volume mapping into the compose format - the copy stuff will need to be done via standard docker however in line with the above.
Note: I wrote the above commands blind, but will check them over at lunch and correct any mistypes - but the concept is correct
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 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.
I would like to know if there is a specific way to upload data to Docker, I've been stuck on this during a week and I am sure the answer will be something simple.
Does anyone know? I am working with a windows 10 machine.
You can mount directories on the host system inside the container and access their contents that way, if that's what you mean by 'data'.
You should check out Manage data in containers for more info.
You can use the docker cp command to copy the file.
For eg: If you want to copy abc.txt to location /usr/local/folder inside some docker container(you can get docker container name from NAMES column by executing command docker ps.) then you just execute,
docker cp abc.txt ContainerName:/usr/local/folder
(abc.txt is a local to the foler from where you are executing the command. You can provide the full path of the file.)
After this just get into the container by,
docker exec -it ContainerName bash
then cd /usr/local/folder. you will see your file copied their.