I am very (read very) new to Docker so experimenting. I have created a very basic Dockerfile to pull in Laravel:
FROM composer:latest
RUN composer_version="$(composer --version)" && echo $composer_version
RUN composer global require laravel/installer
WORKDIR /var/www
RUN composer create-project --prefer-dist laravel/laravel site
My docker-compose.yml file looks like:
version: '3.7'
services:
laravel:
build:
context: .
dockerfile: laravel.dockerfile
container_name: my_laravel
network_mode: host
restart: on-failure
volumes:
- ./site:/var/www/site
When I run docker-compose up, the ./site directory is created but the contents are empty. I've put this in docker-compose as I plan on on including other things like nginx, mysql, php etc
The command:
docker run -v "/where/i/want/data/site:/var/www/site" my_laravel
Results in the same behaviour.
I know the install is successful as I modified my dockerfile with the follwing two lines appended to it:
WORKDIR /var/www/site
RUN ls -la
Which gives me the correct listing.
Clearly misunderstanding something here. Any help appreciated.
EDIT: So, I was able to get this to work... although, it slightly more difficult than just specifying a path..
You can accomplish this by specifying a volume in docker-compose.yml.. The path to the directory (on the host) is labeled as device in the compose file.. It appears that the root of the path has to be an actual volume (possibly a share would work) but the 'destination' of the path can be a directory on the specified volume..
I created a new volume called docker on my machine but I suppose you could do this with your existing disk/volume..
I am on a Mac and this docker-compose.yml file worked for me:
version: '3.7'
services:
nodemon-test:
container_name: my-nodemon-test
image: oze4/nodemon-docker-test
ports:
- "1337:1337"
volumes:
- docker_test_app:/app # see comment below on which name to use here
volumes:
docker_test_app: # use this name under `volumes:` for the service
name: docker_test_app
driver: local
driver_opts:
o: bind
type: none
device: /Volumes/docker/docker_test_app
The container specified exists in my DockerHub.. this is the source code for it, just in case you are worried about anything malicious. I created it like two weeks ago to help someone else on StackOverflow.
Shows files from the container on my machine (the host)..
You can read more about Docker Volume configs here if you would like.
ORIGINAL ANSWER:
It looks like you are trying to share the build directory with your host machine.. After some testing, it appears Docker will overwrite the specified path on the container with the contents of the path on the host.
If you run docker logs my_laravel you should see an error about missing files at /var/www/site.. So, even though the build is successful - once Docker mounts the directory from your machine (./site) onto the container (/var/www/site) it overwrites the path within the container (/var/www/site) with the contents of the path on your host (./site) - which is empty.
To test and make sure the contents of /var/www/site are in fact being overwritten, you can run docker exec -it /bin/bash (you may need to replace /bin/bash with /bash).. This will give you command line access inside of the container. From there you can do ls -a /var/www/site..
Furthermore, you can also pre-stage ./site to have a random test file in it (test.txt or whatever), then docker-compose up -d, then run the same commands from the step above docker exec -it ... and see if the staged test.txt file is now inside the container - this gives you definitive evidence that when you run volumes, the data on your host overwrites data in the container.
With that being said, doing something like this and sharing a log directory will work... the volume path specified on the container is still overwritten, the difference is the container is writing to that path.. it doesn't rely on it for config files/app files.
Hope this helps.
Related
I have the following docker-compose:
version: '3.7'
services:
db:
image: bitnami/mongodb:5.0.6
volumes:
- "/app/local-data:/data/db"
env_file: ./db/.env
The problem is data does not persist between docker-compose up/down and docker does not seem to use /app/local-data even though it creates it.
When I run docker-compose, container starts and works naturally. The directory /app/local-data is created by docker, however Mongodb does not populate it, and no r/w error is being shown on console. This makes me thing a temporary volume is assigned to container instead.. But if that is true then why docker still creates /app/local-data and not using it?
Any ideas how can I debug this?
Docker directives like volumes: don't know anything about what's actually running in the image. That directive creates the specified host and container paths if required, and bind-mounts the host path into the container path. It's up to the application code to use that directory (or not).
If you look at the bitnami/mongodb Docker Hub page under "Persisting your database", the database is configured to store data in the /bitnami/mongodb directory inside the container, and that directory needs to be the second volumes: path. Also note the requirement that the data directory needs to be writable by user ID 1001, which may or may not exist on your host (there's no specific requirement to create it).
volumes:
- "/app/local-data:/bitnami/mongodb"
# ^^^^^^^^^^^^^^^^
sudo chown -R 1001 /app/local-data
sudo docker-compose up -d
Let's say I have a docker-compose file with two containers:
version: "3"
services:
app:
image: someimage:fpm-alpine
volumes:
- myvolume:/var/www/html
web:
image: nginx:alpine
volumes:
- myvolume:/var/www/html
volumes:
myvolume:
The app container contains the application code in the /var/www/html directory which gets updated with each version of the image, so I don't want this directory to be persistent.
Yet I need to share the data with the nginx container. If I use a volume or a host bind the data is persistent and doesn't get updated with a new version. Maybe there is a way to automatically delete a volume whenever I pull a new image? Or a way to share an anonymous volume?
i think its better for you to use anonymous volume
volumes:
- ./:/var/www/html
You would have to be willing to drop back to docker-compose version 2 and use data containers with the volumes_from directive.
Which is equivalent to --volumes-from on a docker run command.
This should work fine. The problem isn't with docker. You can use volumes to communicate in this way. If you run docker-compose up in a directory with the following compose file:
version: "3"
services:
one:
image: ubuntu
command: sleep 100000
volumes:
- vol:/vol
two:
image: ubuntu
command: sleep 100000
volumes:
- vol:/vol
volumes:
vol:
Then, in a 2nd terminal docker exec -it so_one_1 bash (you might have to do a docker ps to find the exact name of the container, it can change). You'll find yourself in a bash container. Change to the /vol directory cd /vol and then echo "wobble" > wibble.txt", then exit` the shell (ctrl-d).
In the same terminal you can then type docker exec -it so_two_1 bash (again, check the names). Just like last time you can cd /vol and type ls -gAlFh you'll see the wibble.txt file we created in the other container. You can even cat wibble.txt to see the contents. It'll be there.
So if the problem isn't docker, what can it be? I think the problem is that nginx isn't seeing the changes on the filesystem. For that, I believe that setting expires -1; inside a location block in the config will actually disable caching completely and may solve the problem (dev only).
Here is a simplified version of my docker-compose.yml (it's the volume in buggy-service that does not behave as I expect):
version: '3.4'
services:
local-db:
image: postgres:9.6
environment:
- DB_NAME=${DB_NAME}
# other env vars (not important)
ports:
- 5432:5432
volumes:
- ~/.docker-volumes/${DB_NAME}/postgresql/data:/var/lib/postgresql/data
- postgresql:/docker-entrypoint-initdb.d
buggy-service:
build:
context: .
dockerfile: Dockerfile.test
target: buggy-image
args:
# bunch of args (not important)
volumes:
- /Users/me/temp:/temp
volumes:
postgresql:
driver_opts:
type: none
device: /Users/me/postgresql
o: bind
If I do docker-compose -f docker-compose.yml up -d local-db, a container for it starts up automatically and I find that /Users/me/postgresql on the host machine (Mac OSX) binds correctly to /docker-entrypoint-initdb.d with content synced.
However, if I do docker-compose -f docker-compose.yml up --build -d buggy-service, a container does not start up automatically.
Question: How do I get buggy-service to behave like local-db, i.e., start up automatically with the required volume mounted?
Here's the stripped down version of Dockerfile.test referenced by buggy-service:
FROM microsoft/dotnet:2.1-sdk-alpine AS buggy-image
# Bunch of ARG definitions (not important)
VOLUME /temp
# other stuff (not important)
ENTRYPOINT ["/bin/bash"]
# Other FROMs
Edit 1
A bit more info about what I’m trying to achieve...
The buggy-container I’m trying to get working runs .Net Core as the base image. Its purpose is to run dotnet test and generate coverage reports, which can then be consumed in the host, which may either be a local dev machine or a build server (in this case, BitBucket pipelines).
... followed by docker run -dit --name buggy-container buggy-image
This command creates a new container, not based on anything in the compose yml file. Without a volume specification, it will only get an anonymous volume since you've defined the volume in the Dockerfile (I tend to recommend against defining a volume there). You can see the anonymous volumes with a docker volume ls command, they'll be the ones with a long unique id and no reference to what they belong to.
To define a host volume from docker run, you need the -v flag:
docker run -dit -v /Users/me/temp:/temp --name buggy-container buggy-image
From your now changed question, you have a new issue. Your container specifies a single command to run in the entrypoint:
ENTRYPOINT ["/bin/bash"]
When bash runs, it reads input from stdin. When that input ends, like when you run a container with no input attached, bash will exit. When the process your container runs exits, the container exits. From the details available, I can't tell you what that command should be, but a good starting point is to look at other images on docker hub that perform a similar task that you're trying to run, and look at the Dockerfile they use (many hub images point back to a GitHub repo with the full source).
I am having problems with writing files out from inside a docker container to my host computer. I believe this is a privilege issue and prefer not to set privileged: True. A work around for writing out files is by pre-pending ../ to a volume in my docker-compose.yml file. For example,
version: '3'
services:
example:
volumes:
- ../:/example
What exactly is ../ doing here? Is it taking from the container's privileges and "going up" a directory to the host machine? Without ../, I am unable to write out files to my host machine.
Specifying a path as the source, as opposed to a volume name, bind mounts a host path to a path inside the container. In your example, ../ will be visible inside the container at /example on a recent version of docker.
Older versions of docker can only access the directory it is in and lower, not higher, unless you specify the higher directory as the context.
To run the docker build from the parent directory:
docker build -f /home/me myapp/Dockerfile
As opposed to
docker build -f /home/me/myapp Dockerfile
Doing the same in composer:
#docker-compose.yml
version: '3.3'
services:
yourservice:
build:
context: /home/me
dockerfile: myapp/Dockerfile
Or with your example:
version: '3'
services:
build:
context: /home/me/app
dockerfile: docker/Dockerfile
example:
volumes:
- /home/me/app:/example
Additionally you have to supply full paths, not relative paths. Ie.
- /home/me/myapp/files/example:/example
If you have a script that is generating the Dockerfile from an unknown path, you can use:
CWD=`pwd`; echo $CWD
To refer to the current working directory. From there you can append /..
Alternately you can build the image from a directory one up, or use a volume which you can share with an image that is run from a higher directory, or you need to output your file to stdout and redirect the output of the command to the file you need from the script that runs it.
See also: Docker: adding a file from a parent directory
The statement volumes: ['../:/example'] makes the parent directory of the directory containing docker-compose.yml on the host (../) visible inside the container at /example. Host directory bind-mounts like this, plus some equivalent constructs using a named volume attached to a specific host directory, are the only way a container can write out to the host filesystem.
I am having some gitcode (around 10gb) kept in a folder "src" in my home directory. I have read somewhere that we can mount this code as a data volume in docker.
I am a newbie to docker. I only have an idea of using "docker volume create" command, but totally unsure about how to use it.
Could someone help me in achieving this.
Bishal's answer has instructions how to use mapping with Docker compose. When using plain docker, use command
docker run -v <absolute path to src folder on host>:<absolute path on container> some-image
# Real example:
docker run -v ~/src:/src some-image
Docker allows for easy volume mapping. This can be configured in your docker-compose.yaml file.
Volume mapping allows you to share a directory in your host machine to your docker-container.
version: '2'
services:
web:
build: .
volumes:
- .:/code
In the above snippet, the files in the current directory of host machine will be mapped to /code of the docker container.
This article has detailed explanation.