7

I actually trying to achieve something with Docker but I'm stuck, there is my problem.

I have my container hosted on EC2 with my web app inside it. My webapp use as database a JCR repository which is basically a file stored where you want. So each time my web app start, if the repository doesn't exist, it create it otherwise it use the existing.

My current docker file look like this https://gist.github.com/agonist/7cab7358379e9dd6e812 ./chameleon.sh start just start my webapp. In this app, I configured where the repository file is located.

Now I creted a EBS volume attached and mounted in my EC2 instance. This volume will be dedicated to store the repository. So basicaly in my app I configure my repository path to /mnt/repository/ where repository is the directory which will contain my repository file created by my web app. But I don't know how I can mount this volume to my container before the ./chameleon.sh start in the Dockefile. As I see during my research 

docker run -v /mnt/repository:/mnt/repository aws_beanstalk/current-app

is not executable from the Dockefile.

I also found stuff about data only container which share a volume with another container, but still the same probleme if I have to run 

sudo docker run -d --volumes-from dbdata

after my container started

agonist_
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  • so /mnt/repository is a *file* **and** the mountpoint? Or is the mountpoint /mnt? and just to be sure: you run docker client on the same instance, not on your local machine with remote DOCKER_HOST? – creack Nov 20 '14 at 16:09
  • I updated the topic to be more clear. /mnt/repository/ is the directory in which the app will save the repository file. And yes I work only on my EC2 instance nothing on my local machine. – agonist_ Nov 20 '14 at 16:30

2 Answers2

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Short version: This is not an answer, just a little help towards it with clarification on how Docker works.

Not directly related, but your Dockerfile should probably look like this:

FROM dockerfile/java:oracle-java8

# Expose the port 9000
EXPOSE 9000

# Volumes
VOLUME /root/wisdom/logs
VOLUME /root/wisdom/application

# Change workdir.
WORKDIR /root/wisdom

RUN touch /root/wisdom.log

# Add the wisdom distribution
ADD . /root/wisdom

# For easier handling, we dump the log, so `docker logs containerId` displays
# the log.
CMD ./chameleon.sh start && tail -F logs/wisdom.log

That way, all your layers before ADD are cached. Whereas before, if you change anything in your directory, all the layers are recreated. You chameleon.sh should be chmod on your local directory, not at runtime. ADD conserve permissions. the stop is not necessary as when you start your container, you have no process running.

The -v is indeed not executable from a Dockerfile. This is expected as Dockerfile are meant to be portable. If you tie it to your local machine, then you lose this feature.

When you do your docker run -v /mnt/repository:/mnt/repository aws_beanstalk/current-app, the mount is done before executing the command. You can double check this by running docker run -v /mnt/repository:/mnt/repository aws_beanstalk/current-app mount

When using --volumes-from, it is the same thing. The volumes are mounted before executing the command.

Why then does it fail? I am unsure, it would be interesting to inspect the mount result and do some manual testing with your EBS. I have some containers mounting EBS volumes and it works fine.

creack
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1

Check out this related question: Mount specific EBS volume to Docker under AWS beanstalk and the AWS Forum question Docker does not see the mount until the docker daemon is restarted.

Community
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Jakub Holý
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