Docker Tomcat users configuration not working - docker

Question

Update: cleanup and directly indicate the problem and the solution.
PROBLEM:
Docker-tomcat was properly installed and running, except for the 403 Access error in the Manager App. It also seems that my docker tomcat cannot find my tomcat-users.xml configuration.
SOLUTION
Thanks to Farhad and Sanket for the answers.
[Files]:
Dockerfile
FROM tomcat:8.5.11
MAINTAINER Borgy Manotoy <borgymanotoy#ujeaze.com>
# Update Apt and then install Nano editor (RUN can be removed)
RUN apt-get update && apt-get install -y \
nano \
&& mkdir -p /usr/local/tomcat/conf
# Copy configurations (Tomcat users, Manager app)
COPY tomcat-users.xml /usr/local/tomcat/conf/
COPY context.xml /usr/local/tomcat/webapps/manager/META-INF/
Tomcat Users Configuration (conf/tomcat-users.xml)
<tomcat-users xmlns="http://tomcat.apache.org/xml"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd"
version="1.0">
<role rolename="manager-gui"/>
<role rolename="manager-script"/>
<user username="admin" password="password" roles="manager-gui,manager-script" />
</tomcat-users>
Application Context (webapps/manager/META-INF/context.xml)
<?xml version="1.0" encoding="UTF-8"?>
<Context antiResourceLocking="false" privileged="true" >
<!--
<Valve className="org.apache.catalina.valves.RemoteAddrValve"
allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />
-->
</Context>
[STEPS & COMMANDS]:
Build Docker Image
docker build -t borgymanotoy/my-tomcat-docker .
Run Image (my-tomcat-docker and set port to 8088)
docker run --name my-tomcat-docker-container -p 8088:8080 -it -d borgymanotoy/my-tomcat-docker
Go to the container's bash (to check files inside the container thru bash)
docker exec -it biyahe-tomcat-docker-container bash

Answer 1

First you need to expose your application in the container, so you can connect to it from dockerhost/network.
docker run -d -p 8000:8080 tomcat:8.5.11-jre8
You need to change 2 files in order to access the mangaer app from remote host. (Browser on Docker host is considered remote, only packets received on containers loopback are considered local for tomcat)
/usr/local/tomcat/webapps/manager/META-INF/context.xml Note the commented section.
<Context antiResourceLocking="false" privileged="true" >
<!--
<Valve className="org.apache.catalina.valves.RemoteAddrValve"
allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />
-->
Please note the commented section.
/usr/local/tomcat/conf/tomcat-users.xml as you stated in the question.
<tomcat-users xmlns="http://tomcat.apache.org/xml"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd"
version="1.0">
<role rolename="manager-gui"/>
<role rolename="manager-script"/>
<user username="admin" password="password" roles="manager-gui,manager-script" />
In order to make changes to files in the container, You can try building your own image, but I suggest using docker volumes or bind mounts.
Also make sure you restart the container so the changes take effect.

Answer 2

Please specify the port when you do a docker run like (i believe mine/tomcat-version is your image name),
docker run -p 8000:8080 -it -d --name MyContainerName mine/tomcat-version
then access the manager page using,
http://<ipaddress>:8000/manager/html
To get the host ip address in docker to need to execute docker-machine ip
Addition info: You can also get into the container using below command,
docker exec -it MyContainerName bash if you want to check different things like tomcat logs, conf files, etc.

Answer 3

Although this is quite late, I wanted to leave my 2 cents.
I took this solution to the next level by building a sample continuous integration system that deploys wars to the docker tomcat just by running mvn clean install via project IDE whilst having the docker tomcat container running.
This solves the problem of having to restart tomcat-container every time a new build is available. Takes advantage of tomcat's auto-deploy
Uses shared volume so that you can deploy multiple wars into the shared volume and a script picks up your wars and deploys to tomcat webapps
Comes with a standard user 'admin' so as to access manager GUI.
Available on public docker repo: docker run -p 8080:8080 -d --name tom -v <YOUR_VOLUME>:/usr/local/stagingwebapps wintersoldier/tomcat_ci:1.0
Picks up any war files dropped to the shared volume and instantly deploys them to tomcat server with an option to deploy it via GUI as well
Here is a sample application with required maven changes & docker file to explore