Develop Reference

Use cp in entrypoint for docker run

There is Dockerfile
FROM openjdk:11.0.12-jre-slim
COPY target/app.jar /app.jar
COPY configs configs
ENTRYPOINT ["java","-jar","/app.jar"]
In folder configs contains json configs for java application.
The build docker command is:
docker build --build-arg -f ~/IdeaProjects/app --no-cache -t app:latest
And the run command is:
docker run --entrypoint="cp configs var/opt/configs/ && java -jar app.jar" app:latest
Let's omit the ability to copy configs in the Dockerfile via COPY command. Unfortunately, this must be done using --entrypoint.
An error occurs when the docker run command was executed:
docker: Error response from daemon: OCI runtime create failed: container_linux.go:370: starting container process caused: exec: "cp configs var/opt/configs/ && java -jar app.jar": stat cp configs var/opt/configs/ && java -jar app.jar: no such file or directory: unknown.
Could you explain why the error occurred in this case?

I would do this with an entrypoint wrapper script. A Dockerfile can have both an ENTRYPOINT and a CMD; if you do, the CMD gets passed as arguments to the ENTRYPOINT. This means you can make the ENTRYPOINT a shell script that does first-time setup, then ends with exec "$#" to replace itself with the CMD.
#!/bin/sh
# docker-entrypoint.sh
# copy the configuration to the right place
cp configs var/opt/configs/
# run the main container command
exec "$#"
In the Dockerfile, make sure to COPY the script in (it should be checked in to source control as executable) and set it as the ENTRYPOINT.
...
COPY docker-entrypoint.sh .
ENTRYPOINT ["./docker-entrypoint.sh"] # must be JSON-array syntax
CMD ["java", "-jar", "/app.jar"] # what was previously ENTRYPOINT
When you run the container it's straightforward to replace the CMD, so you can double-check that this is doing the right thing by running an interactive shell in place of the java application.
docker run -v "$PWD/alt-configs:/configs" --rm -it my-image sh
If you do need to override the command like this at docker run time, the command you show uses && to run two commands consecutively. This needs to run a shell to be understood correctly, and in this context you need to manually provide a /bin/sh -c wrapper.
I would still recommend changing ENTRYPOINT to CMD in your Dockerfile; then you could run a relatively straightforward
docker run \
... \
-v "$PWD/alt-configs:/configs" \
my-image \
/bin/sh -c 'cp configs var/opt/configs && java -jar /app.jar'
If you use --entrypoint, it only takes the first word out of this command, and it is a Docker options so it needs to come before the image name. I'd recommend designing your image to avoid needing this awkward construct.
docker run \
... \
-v "$PWD/alt-configs:/configs" \
--entrypoint /bin/sh \
my-image \
-c 'cp configs var/opt/configs && java -jar /app.jar'
Your proposed command is having problems because it's trying to pass the entire command, including the embedded spaces and shell operators, as a single word, but that causes the OS-level process handling to try to look for an executable file with spaces and ampersands in the filename, hence the "no such file or directory" error.

Docker - Run Wildfly standalone

I have a Ubuntu server with a WildFly standalone installation configured, here i have a Java app that is accesible on port 80, i want to dockerize it. When create the container, i'm copying the entire WildFly directory from my local storage to the container, when i run the command docker run -d --name dej_website -p 80:80 wildfly_dej_website:2.0 the container start, but when try to access in my local machine localhost doesn't works.
What am i doing wrong? How can i do to access to this container, with the configured server?
This is my dockerfile
FROM centos
#INSTALL JAVA
RUN yum -y install java-11-openjdk
RUN java -version
RUN mkdir /opt/DEJ_Wildfly/
#SET OPT AS WORK DIRECTORY
WORKDIR /opt/DEJ_Wildfly/
#COPY WILDFLY SERVER FILES
COPY wildfly-11.0.0.Final .
#DEFINE ENVIRONMENT VARIABLE
ENV JBOSS_HOME /opt/DEJ_Wildfly/wildfly-11.0.0.Final/
#EXECUTE SH FILE
CMD JBOSS_HOME/bin/standalone.sh -b=0.0.0.0
CMD tail -f /var/log/lastlog
#EXPOSE 80
This is the log of docker build --tag wildfly_dej_website:2.0 . command:
Sending build context to Docker daemon 597.4MB
Step 1/9 : FROM centos
---> 300e315adb2f
Step 2/9 : RUN yum -y install java-11-openjdk
---> Using cache
---> f333f6149e02
Step 3/9 : RUN java -version
---> Using cache
---> 0110143899c7
Step 4/9 : RUN mkdir /opt/DEJ_Wildfly/
---> Running in 88bc6f0632c1
Removing intermediate container 88bc6f0632c1
---> c0ab7cc8a364
Step 5/9 : WORKDIR /opt/DEJ_Wildfly/
---> Running in 84705355ac2c
Removing intermediate container 84705355ac2c
---> 6986f8229cb0
Step 6/9 : COPY wildfly-11.0.0.Final .
---> 3caf8ec0e5d0
Step 7/9 : ENV JBOSS_HOME /opt/DEJ_Wildfly/wildfly-11.0.0.Final/
---> Running in b5f649e4e2e0
Removing intermediate container b5f649e4e2e0
---> 27d775c3d0cb
Step 8/9 : CMD JBOSS_HOME/bin/standalone.sh -b=0.0.0.0
---> Running in c7ffddb4bcdf
Removing intermediate container c7ffddb4bcdf
---> 533d3836f94d
Step 9/9 : CMD tail -f /var/log/lastlog
---> Running in f92aca5a63ba
Removing intermediate container f92aca5a63ba
---> 974e6ec6c415
Successfully built 974e6ec6c415
Successfully tagged wildfly_dej_website:2.0
This is the list of containers:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
95ee0139f42c wildfly_dej_website:2.0 "/bin/sh -c 'tail -f…" 4 seconds ago Up 2 seconds 0.0.0.0:80->80/tcp dej_website

The problem here is in your dockerfile.
You need to add a CMD at the end of your dockerfile to run the command you want and keep it running for the docker file to stay alive and provide you with logs through docker logs command.
Add a line like this to your dockerfile:
RUN ./standalone.sh -b 0.0.0.0
CMD tail -f /var/log/syslog
And to make the port accessible on the local machine you'll need to use -p option when issuing the docker run command like this:
docker run -d -p 127.0.0.1:80:8080 <image>
you can find out more here:
https://docs.docker.com/engine/reference/commandline/run/

Docker exit witout throwing an error or executing code

I'm trying to run talend job inside a docker, build goes ok but when I run container it just exits without any error. Here is my dockerfile:
FROM store/oracle/serverjre:8
ARG talend_job=export_data_xml
ENV TALEND_JOB ${talend_job}
ENV ARGS ""
WORKDIR /opt/talend
COPY . /opt/talend
### Install Talend Job
RUN yum install -y unzip && \
unzip ${TALEND_JOB}.zip && \
rm -rf ${TALEND_JOB}.zip && \
chmod +x ${TALEND_JOB}/${TALEND_JOB}_run.sh
VOLUME /data
CMD ["/bin/sh","-c","${TALEND_JOB}/${TALEND_JOB}_run.sh ${ARGS}"]
Run command:
docker run -it demo:latest
It doesn't execute a code or throw error. Any idea what can be wrong or how to debug it at least?
Thanks.

My best guess it would be that is a problem with the file paths.
You can debug it by running your image with:
docker run -ti demo:latest /bin/sh
In order to go inside the container,
check if export_data_xml_run.sh is in the right path (/opt/talend/export_data_xml) and try to run it form there

Some things worth a try:
Add some echo statements after each command, eg:
RUN echo "About to install unzip..." && yum install -y unzip && echo "unzip installed" \
...
If its failing here, you should at least see the echo statements.
Below, it looks like you're setting pwd to /opt/talend, then performing a COPY of whatever is in pwd to the same dir... effectively a null operation.
WORKDIR /opt/talend
COPY . /opt/talend
This last line, be sure to pass the string args as individual strings. I've been working on something recently and the two strings I passed as "command, input" which was treated as a single string, rather than two individual strings (which is what I actually wanted):
CMD ["/bin/sh","-c","${TALEND_JOB}/${TALEND_JOB}_run.sh ${ARGS}"]
You could also log into the docker container to try and debug it once its running using:
docker exec -it [imageId] sh
Once inside the container you can run various commands to validate everything is as you expect it to be.
HTH

Committing container changes of files generated in /workspace (even using makefile) doesn't persist into new instances of the image

I am using a java program which generates a lot of files (i.e ANTLR to generate parsers using a grammar). When I perform:
java -cp "/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH" org.antlr.v4.Tool Java8.g4 && javac *.java
in the interactive shell using a docker image, certain java files and their classes are generated in the current directory.
But when I perform this in the Dockerfile using:
RUN java -cp "/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH" org.antlr.v4.Tool Java8.g4 && javac *.java
the files don't seem to be generated.
Any reason why this is happening and how I could perhaps correct this to generate the files using the RUN instruction in the Dockerfile?
UPDATE 1:
More info, my Dockerfile looks like this:
FROM blah/blah_java
MAINTAINER blabla
RUN apt-get install -y make wget
RUN mkdir -p /usr/java && wget -O java.tar.gz http://download.oracle.com/otn-pub/java/jdk/8u40-b25/jdk-8u40-linux-x64.tar.gz --header "Cookie: oraclelicense=accept-securebackup-cookie" && tar xfz java.tar.gz -C /usr/java
ENV JAVA_HOME /usr/java/jdk1.8.0_40
ENV PATH $PATH:$JAVA_HOME/bin
.
.
.
RUN mkdir -p /usr/local/lib && cd /usr/local/lib && wget http://www.antlr.org/download/antlr-4.5-complete.jar
ENV CLASSPATH=".:/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH"
.
.
.
RUN mkdir -p /workspace/antlr-test/
ADD Java8.g4 /workspace/antlr-test/
WORKDIR /workspace/antlr-test/
RUN java -cp "/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH" org.antlr.v4.Tool Java8.g4 && javac *.java
UPDATE 2:
Outputs something like this on building:
Step 1 : FROM blah/blah_java
---> ff083dedeeac
Step 2 : MAINTAINER blabla
---> Using cache
---> b2cc75d73e93
Step 3 : RUN apt-get install -y make wget
---> Using cache
---> e8f8162ca496
Step 4 : RUN mkdir -p /usr/java && wget -O java.tar.gz http://download.oracle.com/otn-pub/java/jdk/8u40-b25/jdk-8u40-linux-x64.tar.gz --header "Cookie: oraclelicense=accept-securebackup-cookie" && tar xfz java.tar.gz -C /usr/java
---> Using cache
---> 1587950d483a
Step 5 : ENV JAVA_HOME /usr/java/jdk1.8.0_40
---> Using cache
---> 1787ea5c62c4
Step 6 : ENV PATH $PATH:$JAVA_HOME/bin
---> Using cache
---> 5f9082023d2c
.
.
.
Step 10 : RUN mkdir -p /usr/local/lib && cd /usr/local/lib && wget http://www.antlr.org/download/antlr-4.5-complete.jar
---> Using cache
---> 7a67f6c4c572
Step 11 : ENV CLASSPATH ".:/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH"
---> Using cache
---> c64a24b809f0
.
.
.
Step 14 : RUN mkdir -p /workspace/antlr-test/
---> Using cache
---> 27b18aab274f
Step 15 : ADD Java8.g4 /workspace/antlr-test/
---> Using cache
---> 87ace495d90b
Step 16 : WORKDIR /workspace/antlr-test/
---> Using cache
---> 31089935532b
Step 17 : RUN java -cp "/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH" org.antlr.v4.Tool Java8.g4 && javac *.java
---> Using cache
---> 773c302ecf5e
Successfully built 773c302ecf5e
UPDATE 3:
On having 'ls' in the last RUN instruction as:
RUN java -cp "/usr/local/lib/antlr-4.5-complete.jar:$CLASSPATH" org.antlr.v4.Tool Java8.g4 && javac *.java && ls -la
I find that the files generated are listed correctly. It is in committing the changes that this is not working.
UPDATE 4:
I also find that in the interactive shell of the image, the files are generated. But when I commit the changes, they are not visible the next time I run them. On performing a `docker diff , before committing the changes, I find that the files generated are not listen here.
UPDATE 5:
Looks like the files generated are not persisted across image builds/commits if they are in one of the subdirectories in /workspace directory. If they are made to generate outside workspace, they seem to persist through builds/commits.

Docker keeps old build steps as a optimization (this is part of dockers strength).
If you change a Dockerfile and build, the new image will use cache for everything BEFORE the change and rebuild everything after it.
Restoring the changed line in the Dockerfile will re-activate the cached build.
You can invalidate the cache by flags to docker build or you can add lines to your Dockerfile to remind you when you invalidated everything below that part last. For example adding/editing the following line will invalidate the cache below it.
ENV FORCED_DOCKER_REBUILD=2018-01-01

Files not getting added in docker workspace

I have docker file
FROM java:8
# Install maven
RUN apt-get update
RUN apt-get install -y maven
WORKDIR /code/
# Prepare by downloading dependencies
#ADD pom.xml /mmt/CouchBaseClient/CB-RestAPI/CacheService/pom.xml
#RUN ["mvn", "dependency:resolve"]
#RUN ["mvn", "verify"]
ADD cacheService-0.0.1-SNAPSHOT.jar /code/cacheService-0.0.1-SNAPSHOT.jar
ADD couchclient-0.0.1-SNAPSHOT.jar /code/couchclient-0.0.1-SNAPSHOT.jar
EXPOSE 4567
CMD ["/usr/lib/jvm/java-8-openjdk-amd64/bin/java", "-jar", "couchclient-0.0.1-SNAPSHOT.jar server cacheService.yml" ]
When I build this file I get the following output
Sending build context to Docker daemon 35.46 MB
Step 1 : FROM java:8
---> 736600fd4ae5
Step 2 : RUN apt-get update
---> Using cache
---> a3466698c29d
Step 3 : RUN apt-get install -y maven
---> Using cache
---> d0fb8e77f89a
Step 4 : WORKDIR /code/
---> Using cache
---> 197735d2da02
Step 5 : ADD cacheService-0.0.1-SNAPSHOT.jar /code/cacheService-0.0.1-SNAPSHOT.jar
---> 9ba30f5a2144
Removing intermediate container bd3c072ebbc6
Step 6 : ADD couchclient-0.0.1-SNAPSHOT.jar /code/couchclient-0.0.1-SNAPSHOT.jar
---> ef59315ed7fe
Removing intermediate container 0da1a69bdb51
Step 7 : EXPOSE 4567
---> Running in a2b32799dd6c
---> 3fb2b534d7c5
Removing intermediate container a2b32799dd6c
Step 8 : CMD /usr/lib/jvm/java-8-openjdk-amd64/bin/java -jar couchclient-0.0.1-SNAPSHOT.jar server cacheService.yml
---> Running in efb44e2bcdb3
---> 56637dfacc0d
Removing intermediate container efb44e2bcdb3
Successfully built 56637dfacc0d
But no directory named code is being made and so no files are being added even though it is giving no compilation error
Used method suggested by #VonC
ENTRYPOINT ["/usr/lib/jvm/java-8-openjdk-amd64/bin/java", "-jar", "couchclient-0.0.1-SNAPSHOT.jar" ]
and then used this command to run the image
docker run <image> -d <arguments>

First, don't forget that ADD <src>... <dest> can invalidate the cache for all following instructions from the Dockerfile if the contents of <src> have changed. See "Best practices" and use COPY instead of ADD.
In both cases (ADD or COPY), if <dest> doesn’t exist, it is created along with all missing directories in its path.
So no mkdir necessary.
COPY cacheService-0.0.1-SNAPSHOT.jar /code/
COPY couchclient-0.0.1-SNAPSHOT.jar /code/
Otherwise, the file cacheService-0.0.1-SNAPSHOT.jar in the folder /code/cacheService-0.0.1-SNAPSHOT.jar/!
Finally, to be sure that the files are where they should be, open a bash:
docker run --rm -it <yourImage> bash
Or, if you have a running container:
docker exec -it <yourContainer> bash
And check what ls /code returns.
Also:
docker run --rm -it --entrypoint /bin/sh <yourImage> -c "ls -alrt"
The OP Legendary Hunter confirms in the comments the files are there.
The issue comes from the CMD which is not fully in exec form.
Each parameter should be in its own quotes:
CMD ["/usr/lib/jvm/java-8-openjdk-amd64/bin/java", "-jar", "couchclient-0.0.1-SNAPSHOT.jar", "server", "cacheService.yml" ]
If the last parameters are grouped together, CMD tries to access the jar file named "couchclient-0.0.1-SNAPSHOT.jar server cacheService.yml", which obvioulsy does not exist.
Hence the error message:
"Error: Unable to access jarfile couchclient-0.0.1-SNAPSHOT.jar server cacheService.yml"
Instead of using CMD, use ENTRYPOINT (with the sa me exec form, each arg in its own double-quotes), and leave CMD undefined.
That way, the arguments you will add to your docker run command will be passed to the ENTRYPOINT (which runs java -jar ...)
Since "server", "cacheService.yml" are the two arguments to be passed to the running container:
ENTRYPOINT ["/usr/lib/jvm/java-8-openjdk-amd64/bin/java", "-jar", "couchclient-0.0.1-SNAPSHOT.jar" ]
Build and then:
docker run --rm -it <image> server cacheService.yml
Once you know it is working, launch it in detached mode:
docker run -d <image> server cacheService.yml

Try this before WORKDIR line:
RUN mkdir /code