Server Tomcat using Docker on Windows PC - docker

Question

I made a webapp in Java and I would like to test the site locally using Docker.
The war file I created works perfectly but to be read correctly it must be inserted inside this path:
/tomcat/webapps/ROOT/
For these reasons I decided to use this form:
https://hub.docker.com/_/tomcat
In particular I decided to use this Dockerfile:
https://github.com/docker-library/tomcat/blob/ec2d88f0a3b34292c1693e90bdf786e2545a157e/9.0/jre11-slim/Dockerfile
I added this code towards the end:
...
EXPOSE 8080
CMD ["cd /usr/local/tomcat/webapps/"]
CMD ["mv ROOT ROOT.old"]
CMD ["mkdir ROOT"]
COPY ./esercitazione.1.maven/ /usr/local/tomcat/webapps/ROOT/
CMD ["catalina.sh", "run"]
I used this code at the Windows 10 prompt:
D:
cd "D:\DATI\Docker-Tomcat-Win10"
docker build -t tomcat-9-java-11:v2.0 .
docker run -it --rm --name tomcat-9-java-11-container -p 8888:8080 tomcat-9-java-11:v2.0
When I enter this link on the browser:
http://192.168.99.103:8888/
I see this:
https://prnt.sc/n2vti1
I'm a beginner with both Docker and Tomcat and I need a little help.
Inside this path I put my unzipped .war file:
D:\DATI\Docker-Tomcat-Win10\esercitazione.1.maven
Thank you
%%%%%%%%%%%%%%%%%%%%%%%%%%
#Shree Tiwari
%%%%%%%%%%%%%%%%%%%%%%%%%%
First of all thank you for your help!
I deleted all the containers and all the images on Docker and used your Dockerfile (I only changed the name of the folder containing the .war files to be tested).
FROM tomcat:9-jre8
ENV JAVA_OPTS="-Xms512m -Xmx1024m -XX:MaxPermSize=256m -XX:MaxMetaspaceSize=128m"
WORKDIR /usr/local/tomcat/webapps/
RUN rm -rf /usr/local/tomcat/webapps/*
COPY ./webapps/*.war /usr/local/tomcat/webapps
EXPOSE 8080
CMD ["catalina.sh", "run"]
I placed the .war file at this address:
D:\DATI\Docker-Tomcat-Win10\webapps\esercitazione.1.maven.war
I opened the Windows prompt and I typed:
D:
cd "D:\DATI\Docker-Tomcat-Win10"
docker build -t tomcat:v1.0 .
docker run -it --rm --name tomcat-container -p 8888:8080 tomcat:v1.0
I entered this URL in the browser:
http://192.168.99.103:8888/esercitazione.1.maven/
then this other:
http://192.168.99.103:8888/
Unfortunately none of them went well.
The only mistake I encountered when creating the image is this:
"SECURITY WARNING: You are building to Docker image from Windows against a non-Windows Docker host. Files and directories added to build context will have '-rwxr-xr-x' permissions. It is recommended to double check and reset permissions for sensitive files and directories."
%%%%%%%%%%%%%%%%%%%%%%%%%%
#Miq
%%%%%%%%%%%%%%%%%%%%%%%%%%
First of all thank you for your help!
I also tested your code but it doesn't work.
Dockerfile:
FROM tomcat:9-jre11-slim
RUN mv webapps/ROOT webapps/ROOT.old && mkdir webapps/ROOT
COPY ./esercitazione.1.maven/ webapps/ROOT/
Code:
D:
cd "D:\DATI\Docker-Tomcat-Win10"
docker build -t tomcat:v2.0 .
docker run -it --rm --name tomcat-container tomcat:v2.0
Browser:
http://192.168.99.103:8080/
Other tests:
FROM tomcat:9-jre11-slim
ENV JAVA_OPTS="-Xms512m -Xmx1024m -XX:MaxPermSize=256m -XX:MaxMetaspaceSize=128m"
RUN mv webapps/ROOT webapps/ROOT.old && mkdir webapps/ROOT
WORKDIR /usr/local/tomcat/webapps/
RUN rm -rf /usr/local/tomcat/webapps/ROOT/*
COPY ./webapps/*.war /usr/local/tomcat/webapps/ROOT/
EXPOSE 8080
CMD ["catalina.sh", "run"]
docker ps -a
docker images
docker stop tomcat-container
docker rmi tomcat:v3.0
D:
cd "D:\DATI\Docker-Tomcat-Win10"
docker build -t tomcat:v3.0 .
docker run -d --name tomcat-container -p 8888:8080 tomcat:v3.0
http://192.168.99.103:8888/
%%%%%%%%%%%%%%%%%%%%%%%%%%
Other tests: (8 April 2019)
FROM tomcat:9.0.17-jre11-slim
LABEL Author="Nome Cognome"
EXPOSE 8080
RUN rm -fr /usr/local/tomcat/webapps/ROOT
COPY ./esercitazione.1.maven.war /usr/local/tomcat/webapps/ROOT.war
CMD ["catalina.sh", "run"]
>
docker build -t tomcat-eb:v.9.0.17 .
docker run -it --rm -p 8888:8080 tomcat-eb:v.9.0.17
>
I'm going here:
http://192.168.99.103:8888
and the browser sends me here:
https://192.168.99.103:8443
%%%%%%%%%%%%%%%%%%%%%%%%%%
Other tests: (I choose another image)
FROM tomee:8-jre-8.0.0-M2-webprofile
LABEL Author="Nome Cognome"
EXPOSE 8080
RUN rm -fr /usr/local/tomcat/webapps/ROOT
COPY ./esercitazione.1.maven.war /usr/local/tomcat/webapps/ROOT.war
CMD ["catalina.sh", "run"]
>
docker build -t tomcat-eb:v.9.0.17 .
docker run -it --rm -p 8888:8080 tomcat-eb:v.9.0.17
>
If I go here:
http://192.168.99.103:8888
I see Tomcat home, non my webapp.
Is this a problem without a solution?

Answer 1

The biggest problem I see here is that you use CMD instead RUN in your dockerfile. CMD is to define a command that will be run when container is ran. With the Dockerfile you have now, only the last one is executed when you start your container and all of those mkdirs, moves, etc. are never executed. As said, you need to use RUN keywords to indicate command that build process should execute and commit as image layer. You probably also do not need the catalina.sh CMD as it might come from the image you base on, but you need to check it on doc page for the base image or take a peek to it's Dockerfile or use docker history imagename To see the layers and commands used to create them.
I took a deeper look into this and the base image you use. In addition to the CMD's your problem is that you change the workdir by running cd commands. catalina.sh exists in $CATALINA_HOME dir, which then is marked as workdir in base image. When you change the active directory by executing cd it breaks the image runtime.
I'd suggest you try with following dockerfile:
FROM tomcat:9-jre11-slim
RUN mv webapps/ROOT webapps/ROOT.old && mkdir webapps/ROOT
COPY ./esercitazione.1.maven/ webapps/ROOT/
No need to use EXPOSE and CMD as they are defined in base image. also, base image defines WORKDIR to $CATALINA_HOME and that's where you will be when executing any following commands (treat WORKDIR as cd but in docker style).
Hope that helps.

Answer 2

First you need to compile your Code to a war file then you can use below Dockerfile
FROM tomcat:9-jre8
ENV JAVA_OPTS="-Xms512m -Xmx1024m -XX:MaxPermSize=256m -XX:MaxMetaspaceSize=128m"
WORKDIR /usr/local/tomcat/webapps/
RUN rm -rf /usr/local/tomcat/webapps/*
COPY ./esercitazione.1.maven/*.war /usr/local/tomcat/webapps
EXPOSE 8080
CMD ["catalina.sh", "run"]