How to run jar file using docker file in docker container

Question

I write the docker file for run the jar file and it does not create the log file for see the console below is my docker file

From ubuntu 
RUN apt-get update && \
    apt-get upgrade -y && \
    apt-get install -y  software-properties-common && \
    add-apt-repository ppa:webupd8team/java -y && \
    apt-get update && \
    echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | /usr/bin/debconf-set-selections && \
    apt-get install -y oracle-java8-installer && \
    apt-get clean
VOLUME /temp
RUN apt-get install -y vim
ADD real_estate_false.jar /real_estate_false.jar
COPY real_estate_false_lib /real_estate_false_lib
COPY resources /resources
COPY testxml /testxml
CMD ["java","-jar","/real_estate_false.jar",">","var/log/jar.log"]

Answer 1

To just run myapp.jar in docker (e.g. to avoid installing java on the host) you can just run:

docker run -v `pwd`:/mnt java:8 java -jar /mnt/myapp.jar

Answer 2

The exec form of CMD doesn't know what redirection is, that's a shell feature.

Either use stdout for logging.

CMD ["java","-jar","/real_estate_false.jar"]

If you really need a log file in the container, run the command in a shell

CMD ["sh", "-c", "java -jar /real_estate_false.jar > var/log/jar.log"]
CMD java -jar /real_estate_false.jar > var/log/jar.log

Answer 3

Why are you creating a logging file inside the container? Configuring a logging driver would be more flexible.

The following example is contrived, but demonstrates how logging events from all your containers could be collected. I suggest reading further into the options available from fluentd

Example

First run fluentd within a container to collect log events

mkdir log
docker run -d --name fluentd -p 24224:24224 -v $PWD:/fluentd/etc -v $PWD/log:/fluentd/log -e FLUENTD_CONF=log.conf fluent/fluentd

Now run a container that creates an event to be logged:

docker run --log-driver=fluentd ubuntu echo hello world

The sample configuration sends log events to an output log file

├── log
│   └── events.20160901.b53b670f22298bbcb
└── log.conf

log.conf

<source>
  @type  forward
  port  24224
</source>

<match **>
   @type file
   path         /fluentd/log/events
   append       true
</match>

---

Additional

Are you married to the Oracle JDK? The following Dockerfile would be considerable simpler:

FROM openjdk:8
ADD target/demo-1.0.jar /opt/demo/demo-1.0.jar
CMD ["java","-jar","/opt/demo/demo-1.0.jar"]