如何使用spotify docker client连接到主机上的docker守护程序

Question

I want to run a Java Spring application inside of a docker container and this application should be able to deploy sibling containers. When I run the Java application directly on my machine it works fine and can deploy containers, but as soon as I try to run the application inside a container it does not work any more (im using supervisord to run the mongodb and Java Spring app in one container and I know that thats not best practice). The container starts up fine, but crashes as soon as my application tries to connect to the docker deamon without any stacktraces from Java, just the error WARN received SIGTERM indicating exit request . The supervisord logs dont contain additional info.

I tried mounting the docker socket from the host (Windows 10 Pro with Docker Desktop, also tried Ubuntu Server 18.04) into the container using -v /var/run/docker.sock:/var/run/docker.sock . I also tried to use --net="host" . Both did not work, although with the second one the container does not crash but produces a different error ( {}->unix://localhost:80: Connection refused ) visible in the log of my java application, which indicates that it cant even find the right address for the deamon. I also activated "Expose deamon on tcp://localhost:2375 without TLS". I also tried to set the DOCKER_HOST environment variable inside the container to default values such as "tcp://localhost:2375" or "/var/run/docker.sock".

Here is the code that I use to initialize the docker client.

DockerClient docker = DefaultDockerClient.fromEnv().build();

The DefaultDockerClient.fromEnv().build(); should create a docker client that uses the DOCKER_HOST environment variable to connect to the host or the default adress ("/var/run/docker.sock" on *NIX).

Here is my DOCKERFILE:

FROM    openjdk:8-jre-alpine

ENV     PACKAGES mongodb supervisor

VOLUME  /opt/server
VOLUME  /data/db
WORKDIR /opt/accservermanager

ADD     supervisord.conf /etc/supervisor.conf
ADD     accservermanager.jar /opt/accservermanager/accservermanager.jar
ADD     application.properties /opt/accservermanager/application.properties

RUN     apk update && \
        apk add --update $PACKAGES --no-cache && \
        rm -rf /var/cache/apk/*

EXPOSE  8000

CMD     ["/usr/bin/supervisord", "-n", "-c", "/etc/supervisor.conf"]

And finally, my supervisord.conf

[supervisord]
user=root
stderr_logfile=/var/log/supervisord.err.log
stdout_logfile=/var/log/supervisord.out.log
loglevel=debug

[program:mongodb]
command=mongod --smallfiles
autostart=true
autorestart=true
stderr_logfile=/var/log/mongo.err.log
stdout_logfile=/var/log/mongo.out.log

[program:accservermanager]
directory=/opt/accservermanager/
command=java -jar accservermanager.jar
autostart=true
autorestart=true
stderr_logfile=/var/log/accservermanager.err.log
stdout_logfile=/var/log/accservermanager.out.log

Expected result: Application connects to the docker client from the host and is able to deploy/manage containers on the host

Actual result: Container crashes or outputs errors.

Answer 1

Turns out that there is a new version of spotify-docker that fixes my problem. Updating from v8.15.1 to v8.15.2 solved my issue.