Serving two sites from one server with Nginx

I have a Rails app up and running on my server and now I'd like to add another one.

I want Nginx to check what the request is for and split traffic based on domain name

Both sites have their own nginx.conf symlinked into sites-enabled, but I get an error starting nginx Starting nginx: nginx: [emerg] duplicate listen options for 0.0.0.0:80 in /etc/nginx/sites-enabled/bubbles:6

They are both listening on 80 but for different things.

Site #1

upstream blog_unicorn {
  server unix:/tmp/unicorn.blog.sock fail_timeout=0;
}

server {
  listen 80 default deferred;
  server_name walrus.com www.walrus.com;
  root /home/deployer/apps/blog/current/public;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @blog_unicorn;
  location @blog_unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://blog_unicorn;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}

Site two:

upstream bubbles_unicorn {
  server unix:/tmp/unicorn.bubbles.sock fail_timeout=0;
}

server {
  listen 80 default deferred;
  server_name bubbles.com www.bubbles.com;
  root /home/deployer/apps/bubbles/current/public;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @bubbles_unicorn;
  location @bubbles_unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://bubbles_unicorn;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}

The documentation says:

> The default_server parameter, if present, will cause the server to become the default server for the specified address:port pair.

It's also obvious, there can be only one default server.

And it is also says:

> A listen directive can have several additional parameters specific to socket-related system calls. They can be specified in any listen directive, but only once for the given address:port pair.

So, you should remove default and deferred from one of the listen 80 directives. And same applies to ipv6only=on directive as well.

Just hit this same issue, but the duplicate default_server directive was not the only cause of this message.

You can only use the backlog parameter on one of the server_name directives.

Example

site 1:

server {
    listen 80 default_server backlog=2048;
    server_name www.example.com;
    location / {
        proxy_pass http://www_server;
    }

site 2:

server {
    listen 80;    ## NOT NOT DUPLICATE THESE SETTINGS 'default_server backlog=2048;'
    server_name blogs.example.com;
    location / {
        proxy_pass http://blog_server;
    }

I was having the same issue. I fixed it by modifying my /etc/nginx/sites-available/example2.com file. I changed the server block to

server {
        listen 443 ssl; # modified: was listen 80;
        listen [::]:443; #modified: was listen [::]:80;
        . . .
}

And in /etc/nginx/sites-available/example1.com I commented out listen 80 and listen [::]:80 because the server block had already been configured for 443.