Question

How to Host Multiple Docker Containers on a Single Droplet with Nginx Reverse Proxy?

Hi all!

Recently I had to setup a few small Docker containers for a couple of small websites.

As the sites were really small I didn’t want to run each one on a separate Droplet, so instead, I used Nginx with separate Nginx server blocks for each site and a reverse proxy for each Docker container.

Here’s how I set that up:


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Accepted Answer

Prerequisites

Before you start, make sure to have Docker and Nginx installed, here’s how to do that:

  • To install Docker follow the steps here:

https://www.digitalocean.com/community/questions/how-to-install-and-run-docker-on-digitalocean-dorplet

  • To install Nginx follow the steps here:

https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-18-04

Once you have both installed, you can continue with the steps:

Step 1 - run your Docker containers

For the same of simplicity, I will run a simple and I’ll run 2 small httpd containers.

  • Run your first container and map port 8080 on your host:
docker run -dit --name container-1 -p 8080:80 httpd:2.4

Now if you visit http://your-dropets-ip:8080, you should be able to see a message saying It Works!.

Just so that we could differentiate the two containers, let’s update the It works! message with Container 1 for example:

  • First get your container ID
docker ps

Then run the following sed command to update the message:

docker exec CONTAINER_ID sed -i 's/It works!/Container 1/' /usr/local/apache2/htdocs/index.html
```

This would basically run a search and replace for the `It works!` string and update it with `Container 1` in the default `index.html` file in the container itself.

If you visit your Droplet's IP again in your browser the message should change from `It works!` to `Container 1`.

Let's do the same thing for container 2, but map it to port `8081` instead:

```
docker run -dit --name container-2 -p 8081:80 httpd:2.4
```

Then agian get your container ID

```
docker ps
```

Then run the `sed` command again to update the `It works!` message to `Container 2`:

docker exec CONTAINER_ID sed -i ‘s/It works!/Container 2/’ /usr/local/apache2/htdocs/index.html


Now if you visit http://your-dropets-ip:8081, you should be able to see a message saying `Container 2`. 

## Step 2 - Configure Nginx

Now that we have our containers up and running we can go ahead and configure our Nginx server blocks, I will go ahead and use the following two subdomain names for this example:

* container1.bobbyiliev.com
* container2.bobbyiliev.com

To keep things as simple as possible, I will create 2 server blocks with the following content:

* Server block #1:

Create a new file called `container1.bobbyiliev.com.conf` in the `/etc/nginx/sites-available/` directory and add the following content:

server { listen 80; server_name container1.bobbyiliev.com;

location / { proxy_pass http://localhost:8080; } }


* Server block #2:

Create a new file called `container2.bobbyiliev.com.conf` in the `/etc/nginx/sites-available/` directory and add the following content:

server { listen 80; server_name container2.bobbyiliev.com;

location / { proxy_pass http://localhost:8081; } }


Then once you have the two config files ready `cd` to the `/etc/nginx/sites-enabled` directory, and run the following commands:

ln -s …/sites-available/container1.bobbyiliev.com.conf .

ln -s …/sites-available/container2.bobbyiliev.com.conf .


Run a config test to make sure that there are no errors:

nginx -t


And if you get `Syntax OK` message, restart Nginx:

systemctl restart nginx


Note, for more information about Nginx server blocks, I would recommend taking a look at this tutorial here:

https://www.digitalocean.com/community/tutorials/how-to-set-up-nginx-server-blocks-virtual-hosts-on-ubuntu-16-04

## Step 3 - Test the setup

That is pretty much it, now if I visit container1.bobbyiliev.com I should be able to see the `Container 1` message and the same for container2.bobbyiliev.com. 

To test that I could run a simple `curl` request:

```command
curl container1.bobbyiliev.com

You should see the following output

<h1>Container 1</h1>

Then run the same request for container2.bobbyiliev.com:

  1. curl container2.bobbyiliev.com

And agian you should see the following output

<h1>Container 2</h1>

Video Demo

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

Conclusion

Now you have 2 different containers on the same Droplet being served from different domain names! Of course, this is just a very basic example, you could go a lot further by expanding your Nginx config a lot more, for example adding more headers to your Nginx proxy pass and even installing a Let’s Encrypt SSL.

Hope that this helps! Let me know if you have any questions! Regards, Bobby

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Hi Bobby, Thank you very much for your tutorial,

What I want to achieve seems quite straightforward but I’ve been battling it for days now

I have a container for my frontend react app pulled in and running, same for my node-typescript app.

I mapped the frontend to port 3000 and the backend to 8000

I then set up Nginx to route the root requests to 3000 and then the request to the IP:8000 to /api

The frontend works fine but for some reason, I can’t seem to get the backend to work the way I want it.

When I visit the http://myIP:8000 it works from postman but when I use my https://server_address/api, the request comes back as bad gateway, tried a couple of solutions online but to no avail yet.

I will look forward to your response

Hi @bobbyiliev !

Thank you for your swift reply, this sorted things out. I created a ’ docker-compose.yml-file for all 3 containers, kept the nginx-proxy.conf :

version: '3.7'

services:

  proxy:
    image: jwilder/nginx-proxy:0.7.0
    container_name: proxy-test
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - ./nginx-proxy.conf:/etc/nginx/conf.d/nginx-proxy.conf:ro

  container1:
    image: httpd:2.4
    container_name: container-1
    environment:
      VIRTUAL_HOST: container1.bobbyiliev.com
    ports:
      - 8080:80

  container2:
    image: httpd:2.4
    container_name: container-2
    environment:
      VIRTUAL_HOST: container2.bobbyiliev.com
    ports:
      - 8081:80

And nginx-proxy.conf according to your instructions

server {
    listen          80;
    server_name     container1.bobbyiliev.com;
    location / {
        proxy_pass http://container-1;
    }
}

server {
    listen        80;
    server_name   container2.bobbyiliev.com;

    location / {
      proxy_pass  http://container-2;
    }
}
  1. docker exec container-1 sed -i ‘s/It works!/Container 1/’ /usr/local/apache2/htdocs/index.html
  2. docker exec container-2 sed -i ‘s/It works!/Container 2/’ /usr/local/apache2/htdocs/index.html
> curl localhost:8081
<html><body><h1>Container 2</h1></body></html>
> curl localhost:8080
<html><body><h1>Container 1</h1></body></html>

> curl container1.bobbyiliev.com
<html><body><h1>Container 1</h1></body></html>
> curl container2.bobbyiliev.com
<html><body><h1>Container 2</h1></body></html>

Thanks for that clarification, it really helped!

Another way that works the same way ? Still, if I leave the out the nginx-proxy.conf-file then the following attributes ‘VIRTUAL_HOST’ and ‘ports’ in the docker-compose.yml-file will map the domain correctly. <p> What is the benefits of using an nginx-proxy.conf in that case ?

And this , follow-up question goes a bit beyond your post, that would be putting an Matomo-ID (wrapped in a javascript) in the nginx-configuration file instead of cluttering up my different services with the Matomo-ID

Best, Inkimar

matomo