Serving two sites from one server with Nginx - proxy

Question

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;
}

Answer 1

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.

Answer 2

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;
}

Answer 3

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.