Nginx status endpoint running inside Docker

Question

I'm new to Nginx, which I'm running in a Docker container to serve a simple website. I want to add an /health endpoint that simply returns status 200 + some arbitrary content.

I copied and adjusted the standard nginx.conf from /etc/nginx/ by adding

server {
    location /health {
        return 200 "alive";
    }
}

at the bottom inside the http block. But when I run the Docker, and try to access localhost/health, I just get no such file or directory. Accessing the website at localhost works fine.

I also tried copying other code blocks, e.g., this one: https://gist.github.com/dhrrgn/8650077 But then I get conflicting server name "" on 0.0.0.0:80, ignored nginx: [warn] conflicting server name "" on 0.0.0.0:80, ignored.

Am I placing the location at a wrong location inside nginx.conf? Do I need some special server configuration? What's the problem?

score 9 · Accepted Answer · answered May 15 '18 at 08:17

9

The problem was with my Nginx Docker setup/configuration: I am using nginx:alpine, which has the configuration files at /etc/nginx/conf.d/. There, default.conf defines the default configuration of Nginx. So, I had to remove default.conf and copy my configuration there instead. In the Dockerfile:

COPY nginx.conf /etc/nginx/conf.d/nginx.conf
RUN rm /etc/nginx/conf.d/default.conf

Of course, I also had to define the standard route in nginx.conf then:

server {
    location / {
        root /usr/share/nginx/html;
    }

    location /health {
        return 200 'alive';
        add_header Content-Type text/plain;
    }
}

answered May 15 '18 at 08:17

stefanbschneider

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So we can't add /health in default.conf ? – Learner Jan 16 '20 at 05:17
@Learner I don't think we can - I just went through this, and had to remove the `default.conf` before my custom nginx config would work. – jndietz Aug 16 '23 at 20:07

Marco Vargas · Answer 2 · 2020-12-18T17:43:09.393

In case you want to do it in one line without building an image, you can just do the following:

#1 Create Nginx.conf file

nano /tmp/nginx-tester/nginx.conf

and put the following content there:

events {}

http {
   server {
       location / {
           root /usr/share/nginx/html;
       }
   
       location /health {
           return 200 '{"status":"UP"}';
           add_header Content-Type application/json;
       }
   }
}

If you see, all what it's doing is to serve a http status 200 with a json stating the status is UP

#2 Run the NgInx Image

Just to have it in one line, and avoid keep recreating the image each time, you can just specify a volume like this:

docker run -it --rm -d -p 8077:80 --name nginx-tester -v /tmp/nginx-tester/nginx.conf:/etc/nginx/nginx.conf:ro nginx

-it: interactive processes (like a shell)
--rm: the container is removed when it exits
-p 8077:80: hostPort:containerPort
--name: Name of the Container
-v: Bind mount a volume (fileHost:fileContainer:ReadOnly)
nginx: Image that will be downloaded and ran

#3 Test it

You can do it just by going to the server:8077 (Which was the port you specified at the step #2)

~ > curl http://myserver:8077/health
{"status":"UP"}

This way you can change the config file, and by just doing a:

docker restart nginx-tester

You are able to reload the file without the need of rebuilding the image.

Nginx status endpoint running inside Docker

2 Answers2