Consul and Tomcat in the same docker container

This is a two-part question.

First part: What is the best approach to run Consul and a Tomcat in the same docker container?

I've built my own image, installing both Tomcat and Consul correctly, but I am not sure on how to start them. I tried putting both calls as CMD in the Dockerfile, but no success. I tried to put Consul as an ENTRYPOINT (Dockerfile) and Tomcat to be called in the "docker run" command. It could be vice versa but I have a feeling that it is no good way either.

The docker will run in one AWS instance. Each docker container would run Consul as a server, to register themselves in another AWS instance. Consul and Consul-template will be integrated into proper load balance. This way, my HAproxy instance will be able to correctly forward the requests as I plug or unplug containers.

Second part: In individual tests I did, the docker container was able to reach my main Consul server(leader) but it failed to register itself as an "alive" node.

Reading the logs at Consul server, I think is a matter of which ports I am exposing and publishing. In AWS, I already allowed communication in all ports in TCP and UDP between the instances in this particular Security Group.

Do you know which ports I should be exposing and publishing to allow proper communication between a standalone consul(aws instance) and consul servers (running inside docker containers inside a aws container)? What is command to run the docker container: docker run -p 8300:8300 .........

Thank you.

I would use ENTRYPOINT to kick off a script on docker run.

Something like

ENTRYPOINT myamazingbashscript.sh

Syntax might be off but u get the idea

The script should start both services and finally should tail -f the tomcat logs (or any logs).

tail -f will prevent container exit since the tail -f command never exits and it will also help u to see what tomcat is doing

Do ... docker logs -f to watch the logs after a docker run

Note because the container doesn't exit u can exec into it with ... docker exec -it containerName bash

This lets you have a sniff around inside the container

Not generally the best approach to have two services in one container because it destroys the separation of concerns and reusability but u may have valid reasons

To build use docker build then run with docker run as u stated it.

If u decided to go for a 2 container solution then u will need to expose ports between containers to allow them to talk to each other. You could share files between containers using volumes_from