如何从主机外部（同一网络）连接到在 docker 容器内运行的 activemq 代理 [Windows]

Question

I created an embedded ActiveMQ, and I could start it inside a Tomcat and connect successfully to the broker on my localhost without docker.

broker.addConnector("tcp://" +  System.getProperty("JMS_HOST") + ":" + System.getProperty(JMS_PORT));

ActiveMQ JMS Message Broker (My-Broker-7777, ID:My-PC-64834-1660051787310-0:0) started

Then I used this embedded ActiveMQ inside a docker container with Tomcat and started successfully.

ActiveMQ JMS Message Broker (My-Broker-7777, ID:d2051a39295f-41549-1660080225701-0:0) started

I connected to the ActiveMQ inside the container and got the error.

javax.jms.JMSException: Could not connect to broker URL: tcp://0.0.0.0:7777. Reason: java.net.ConnectException: Connection refused.

My Dokerfile

FROM tomcat:9-jre8
RUN rm -rf /usr/local/tomcat/webapps/*
RUN mv /usr/local/tomcat/webapps.dist/* /usr/local/tomcat/webapps
COPY ./tomcat/tomcat-users.xml  /usr/local/tomcat/conf
COPY ./tomcat/context.xml  /usr/local/tomcat/webapps/manager/META-INF
COPY ./dist/my-broker-1.0.war  /usr/local/tomcat/webapps
ENV JPDA_ADDRESS=0.0.0.0:8000
ENV JPDA_TRANSPORT=dt_socket
EXPOSE 8080
EXPOSE 7777
ENV JAVA_OPTS="-DJMS_PORT=7777 -DJMS_HOST=0.0.0.0"
CMD ["catalina.sh", "jpda", "run"]

docker run -it -p 8089:8080 --name my-broker my-broker

I could access the Tomcat manager via localhost:8089

I have tried to change JMS_HOST to 'localhost' or remove JMS_HOST property inside the container, but the error is the same.

Below is the code I used to connect to the ActiveMQ from another tomcat on my local machine. I also tried to set JMS_HOST of this Tomcat as 'localhost' or '0.0.0.0'

<bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
    <property name="brokerURL" value="tcp://${JMS_HOST}:${JMS_PORT}"/>
</bean>

Is my approach correct? I am not sure my technique is allowed in the docker world. Thank you for your attention.

Answer 1

I found the problem was why I could not connect to the ActiveMQ, which running inside a container with Tomcat from another Tomcat outside on the local machine.

I modified the docker run as below

docker run -it -p 8089:8080 -p 7777:7777 --name my-broker my-broker

The JMS_HOST is not important in my case, it can be 'localhost' or '0.0.0.0'