Question

How to run multiple containers of the same image and expose different ports?

Posted on April 15, 2020
Container Docker
Asked by mgalland

Dear community,

I have built a droplet with Ubuntu 18.04 and Docker CE edition. For teaching purposes, I want to run 18 times the same container based on a Docker image hosted on DockerHub: https://hub.docker.com/repository/docker/scienceparkstudygroup/master-gls

When I run one container and expose it on the 8787 port, everything runs smoothly and I can access the RStudio instance at my droplet IP address + :8787.

docker run --rm --name rstudio -e PASSWORD=mypwd -p 8787:8787 scienceparkstudygroup/master-gls:openr-latest

My problem is to create multiple instances of the same container but expose it to different ports. I have tried Docker-compose but no success so far.

Any idea? In advance thank you Marc

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Bobby Iliev

Site Moderator

• April 15, 2020

Accepted Answer

Hi there @mgalland,

You would just need to adjust the -p argument and change the first part from 8787 to the new port that you would like to use.

For example:

Starting the first container on port 8787:

docker run --rm --name rstudio-1 -e PASSWORD=mypwd -p 8787:8787 scienceparkstudygroup/master-gls:openr-latest

Starting the second container on port 8788:

docker run --rm --name rstudio-2 -e PASSWORD=mypwd -p 8788:8787 scienceparkstudygroup/master-gls:openr-latest

Note: Make sure to use different names as well otherwise it would not work.

You could also add Nginx as a reverse proxy to the set up:

https://www.digitalocean.com/community/questions/how-to-host-multiple-docker-containers-on-a-single-droplet-with-nginx-reverse-proxy

Here’s a quick video demo on how to do the above:

Hope that this helps! Regards, Bobby

mgalland • April 15, 2020

Hello bobby Thank you, it worked like a charm. I am now running my containers with the --detach option. Still struggling a bit to mount a volume within my machine for each container but I’ll probably figure this out myself. Thanks again marc