How do I share a docker-compose volume with a linux host? - docker

I have a docker-compose.yml
version: '3.3'
services:
ssh:
environment:
- TZ=Etc/UTC
- DEBIAN_FRONTEND=noninterative
build:
context: './'
dockerfile: Dockerfile
ports:
- '172.17.0.2:22:22'
- '443:443'
- '8025:8025'
volumes:
- srv:/srv:rw
restart: always
volumes:
srv:
After I run docker-compose up --build I can ssh to the docker vm and there are files in /srv. 'docker volume ls' shows 2 volumes, srv and dockersetupsrv. They are both in /var/lib/docker/volumes. They both contain _data directories and show creation time stamps that match the docker image creation times but are otherwise empty. Neither one contains any of the files that are in the docker container's /srv directory. How can I share the docker /srv directory with the host?

you should point out more specific for the mapping directory,
for example:
/srv:/usr/srv:rw
after that, when you add content inside your host machine /srv,it is automatically map into /usr/srv
--> make sure that directory exist
you can have a check in this link : https://docs.docker.com/storage/volumes/

Related

How bind properly container's content to host folder?

I'm tring to bind container's content to host folder, so that i can easy edit it, but for some reason it doesn't work!
here my docker-compose file:
version: "3"
services:
webserver:
image: nginx:mainline-alpine
container_name: webserver
restart: unless-stopped
ports:
- "80:80"
volumes:
- ./config:/etc/nginx/conf.d
Please note that this is my folder structure before the docker-compose command:
-project
--docker-compose.yaml
Thank you in advance
Mounting a folder from the container on the host is not possible.
To achieve what you want consider the following
First launch the container without any volumes defined
Run docker cp webserver:/etc/nginx/conf.d/. ./config to copy the content of /etc/nginx/conf.d/ to your config folder on the host
Kill the container and relaunch it with the config folder mounted on /etc/nginx/conf.d (like in your original example). This will shadow the nginx config in the container with the one on your local machine
When editing the local files it will reflect in the container.
If you want to persist your changes in the image after you are done, create a new Docker image by building the following Dockerfile
FROM nginx:mainline-alpine
COPY ./config/* /etc/nginx/conf.d/

Docker keeps data but creates a new volume from host folder every "run"

It seems to be a misunderstood point from me about volumes. I have a docker-compose file with two services : jobs which is a Flask api built from a Dockerfile (see below), and mongo which is from official MongoDb image.
I have two volumes : - .:/code is linked from my host working directory to /code folder in the container, and a named volume mongodata.
version: "3"
services:
jobs:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
environment:
FLASK_ENV: ${FLASK_ENV}
FLASK_APP: ${FLASK_APP}
depends_on:
- mongo
mongo:
image: "mongo:3.6.21-xenial"
restart: "always"
ports:
- "27017:27017"
volumes:
- mongodata:/data/db
environment:
MONGO_INITDB_ROOT_USERNAME: ${MONGO_INITDB_ROOT_USERNAME}
MONGO_INITDB_ROOT_PASSWORD: ${MONGO_INITDB_ROOT_PASSWORD}
volumes:
mongodata:
Dockerfile for jobs service :
FROM python:3.7-alpine
WORKDIR /code
ENV FLASK_APP=job-checker
ENV FLASK_ENV=development
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
EXPOSE 5000
COPY . .
CMD ["flask", "run", "--host=0.0.0.0"]
Every time I remove these container and re-run, everything is fine, I still have my data in mongodata volume. But when I check the volume list I can see that a new volume is created from - .:/code with a long volume name, for example :
$ docker volume ls
DRIVER VOLUME NAME
local 55c08cd008a1ed1af8345cef01247cbbb29a0fca9385f78859607c2a751a0053
local abe9fd0c415ccf7bf8c77346f31c146e0c1feeac58b3e0e242488a155f6a3927
local job-checker_mongodata
Here I ran docker-compose up, then I removed containers, then ran up again, so I have two volumes from my working folder.
Is this normal that every up create a new volume instead of using the previous one ?
Thanks
Hidden at the end of the Docker Hub mongo image documentation is a note:
This image also defines a volume for /data/configdb...
The image's Dockerfile in turn contains the line
VOLUME /data/db /data/configdb
When you start the container, you mount your own volume over /data/db, but you don't mount anything on the second path. This causes Docker to create an anonymous volume there, which is the volume you're seeing with only a long hex ID.
It should be safe to remove the extra volumes, especially if you're sure they're not attached to a container and they don't have interesting content.
This behavior has nothing to do with the bind mount in the other container; bind mounts never show up in the docker volume ls listing at all.

Docker volume invest host to machine

How can I copy files that are inside the container so I can edit them?
services:
web:
image: jitsi/web
restart: ${RESTART_POLICY}
ports:
- '${HTTP_PORT}:80'
- '${HTTPS_PORT}:443'
volumes:
- ${CONFIG}/web:/config
- ${CONFIG}/web/letsencrypt:/etc/letsencrypt
- ${CONFIG}/transcripts:/usr/share/jitsi-meet/transcripts
I want to access the files in the directory /usr/share/jitsi-meet/transcripts within the container:
base.html connection_optimization favicon.ico head.html index.htmllibs package-lock.json plugin.head.html scripts static transcripts
root#cb7d87c5635f:/usr/share/jitsi-meet#
You can use docker cp command:
sudo docker cp <containerId>:/path/in/container /path/in/host/
And with the same command, you can copy files backwards from the host machine to the Docker container.

Docker / Docker-compose volume fill & share issue

I have a few questions about Docker volumes. I have installed Docker and docker-compose on a fresh host running debian stretch. I managed to get a docker-compose file running for a simple nginx/php-fpm project, both containers mounted on the directory containing the source code. I wanted to try to create a single volume that would be shared across my containers but I have a few issue, and my understanding of the official documentation is not helping.
So this is an idea of what I'm trying to achieve :
Question 1 : Trying to create a volume from a dockerfile on a directory mounted from host
docker-compose.yml :
version: '3'
services:
php:
build:
context: .
dockerfile: php.dockerfile
volumes:
- ./host-project-directory:/project
php.dockerfile :
FROM php:7-fpm
VOLUME project
from my understanding, when running docker-compose we should have a volume created on host containing all files from /project from container. And /project from container should contain all files from ./host-project-directory from host.
If I ls the content of /project on container I can see the files from host, but using docker volume list, there are no volumes created on host, why ?
Question 2 : How to populate and use this volume from another container ?
version: '3'
services:
php:
build:
context: .
dockerfile: php.dockerfile
volumes:
- named-volume:/project
web:
image: nginx
links:
- php
volumes:
- named-volume:/project
volumes:
named-volume:
This should create a volume called 'named-volume' and bind it to /project directories on both containers php and web.
Now, how to populate this volume with content from ./host-project-directory ?
I've tried adding a dockerfile like
ADD ./host-project-directory /project
But nothing changed and the volume remained empty.
I'm sorry if this is due to my lack of experience using Docker but I can't figure out how to make this simple thing work.
Thank you for your time !
For the first question, I try a simple docker file like this:
FROM php:7-fpm
COPY ./project /project
And a docker-compose like this:
version: '3'
services:
php:
build: .
volumes:
- named-volume:/project
web:
image: nginx
links:
- php
volumes:
- named-volume:/project
volumes:
named-volume:
Since you create the volume on docker-compose you don't need to create that in the Dockerfile.
Running docker volume list, I'm able to see the volume created with a local driver. Making ls inside the folder I'm also able to see the file. It's important to note, that the file present in you local directory it's not the same that the file inside the container. So if you edit the files in the host this will not change the files in container. That's because you have your volume created in another path, probably at: /var/lib/docker/volumes/...
This happens because you map the volume to the path, but you not specifies where you want the volume. To do that just make your docker-compose like this:
version: '3'
services:
php:
build: .
volumes:
- ./project:/project
web:
image: nginx
links:
- php
volumes:
- ./project:/project
Making this I'm still able to see the volume with the volume list command but without a name.
So I don't know why you are not able to see the volume in the list.
For question 2:
Doing the example above I have the files inside the container that exists in my local "project" folder.
Please check that the path to the local folder is correct.
A bind mount is not the same thing as a volume. You're defining a named volume here, but wanting the functionality of a bind mount.
Try this
version: '3'
services:
php:
build:
context: .
dockerfile: php.dockerfile
volumes:
- ./host-project-directory:/project
web:
image: nginx
links:
- php
volumes:
- ./host-project-directory:/project

Share volumes between separate docker compose files

I am trying to allow nginx to proxy between multiple containers while also accessing the static files from those containers.
To share volumes between containers created using docker compose, the following works correctly:
version: '3.6'
services:
web:
build:
context: .
dockerfile: ./Dockerfile
image: webtest
command: ./start.sh
volumes:
- .:/code
- static-files:/static/teststaticfiles
nginx:
image: nginx:1.15.8-alpine
ports:
- "80:80"
volumes:
- ./nginx-config:/etc/nginx/conf.d
- static-files:/static/teststaticfiles
depends_on:
- web
volumes:
static-files:
However what I actually require is for the nginx compose file to be in a separate file and also in a completely different folder. In other words, the docker compose up commands would be run separately. I have tried the following:
First compose file:
version: '3.6'
services:
web:
build:
context: .
dockerfile: ./Dockerfile
image: webtest
command: ./start.sh
volumes:
- .:/code
- static-files:/static/teststaticfiles
networks:
- directorylocation-nginx_mynetwork
volumes:
static-files:
networks:
directorylocation-nginx_mynetwork:
external: true
Second compose file (ie: nginx):
version: '3.6'
services:
nginx:
image: nginx:1.15.8-alpine
ports:
- "80:80"
volumes:
- ./nginx-config:/etc/nginx/conf.d
- static-files:/static/teststaticfiles
networks:
- mynetwork
volumes:
static-files:
networks:
mynetwork:
The above two files work correctly in the sense that the site can be viewed. The problem is that the static files are not available in the nginx container. The site therefore displays without any images etc.
One work around which works correctly found here is to change the nginx container static files volume to instead be as follows:
- /var/lib/docker/volumes/directory_static-files/_data:/static/teststaticfiles
The above works correctly, but it seems 'hacky' and brittle. Is there another way to share volumes between containers which are housed in different compose files without needing to map the /var/lib/docker/volumes directory.
By separating the 2 docker-compose.yml files as you did in your question, 2 different volumes are actually created; that's the reason you don't see data from web service inside volume of nginx service, because there are just 2 different volumes.
Example : let's say you have the following structure :
example/
|- web/
|- docker-compose.yml # your first docker compose file
|- nginx/
|- docker-compose.yml # your second docker compose file
Running docker-compose up from web folder (or docker-compose -f web/docker-compose.yml up from example directory) will actually create a volume named web_static-files (name of the volume defined in docker-compose.yml file, prefixed by the folder where this file is located).
So, running docker-compose up from nginx folder will actually create nginx_static-files instead of re-using web_static-files as you want.
You can use the volume created by web/docker-compose.yml by specifying in the 2nd docker compose file (nginx/docker-compose.yml) that this is an external volume, and its name :
volumes:
static-files:
external:
name: web_static-files
Note that if you don't want the volume (and all resources) to be prefixed by the folder name (default), but by something else, you can add -p option to docker-compose command :
docker-compose \
-f web/docker-compose.yml \
-p abcd \
up
This command will now create a volume named abcd_static-files (that you can use in the 2nd docker compose file).
You can also define the volumes creation on its own docker-compose file (like volumes/docker-compose.yml) :
version: '3.6'
volumes:
static-files:
And reference this volume as external, with name volumes_static-files, in web and nginx docker-compose.yml files :
volumes:
volumes_static-files:
external: true
Unfortunately, you cannot set the volume name in docker compose, it will be automatically prefixed. If this is really a problem, you can also create the volume manually (docker volume create static-files) before running any docker-compose up command (I do not recommand this solution though because it adds a manual step that can be forgotten if you reproduce your deployment on another environment).

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