Nginx not rendering puma application - ruby-on-rails

Question

I'm trying to serve my rails application using Puma and Nginx. When ever I got to the page it renders the default nginx page. I've tried with two different configurations. This first fails with "upstream" directive is not allowed here. The second warns Starting nginx: nginx: [warn] conflicting server name "localhost" on 0.0.0.0:80, ignored
(1) overwrite nginx.conf
nginx.conf
upstream puma {
server unix:///home/deploy/apps/exelon-api/shared/tmp/sockets/rails-api-puma.sock;
}
server {
listen 80 default_server deferred;
# server_name example.com;
root /home/deploy/apps/rails-api/current/public;
access_log /home/deploy/apps/rails-api/current/log/nginx.access.log;
error_log /home/deploy/apps/rails-api/current/log/nginx.error.log info;
location ^~ /assets/ {
gzip_static on;
expires max;
add_header Cache-Control public;
}
try_files $uri/index.html $uri #puma;
location #puma {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_pass http://puma;
}
error_page 500 502 503 504 /500.html;
client_max_body_size 10M;
keepalive_timeout 10;
}
(2) using sites enabled
nginx.conf
user nginx;
worker_processes 1;
error_log /var/log/nginx/error.log;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
access_log /var/log/nginx/access.log;
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_requests 100;
keepalive_timeout 65;
gzip on;
gzip_http_version 1.0;
gzip_comp_level 2;
gzip_proxied any;
gzip_vary off;
gzip_types text/plain text/css application/x-javascript text/xml application/xml application/rss+xml application/atom+xml text/javascript application/javascript application/json text/mathml;
gzip_min_length 1000;
gzip_disable "MSIE [1-6]\.";
variables_hash_max_size 1024;
variables_hash_bucket_size 64;
server_names_hash_bucket_size 64;
types_hash_max_size 2048;
types_hash_bucket_size 64;
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
sites-enable/rails-api_production
upstream puma_rails-api_production {
server unix:/home/deploy/apps/rails-api/shared/tmp/sockets/rails-api-puma.sock fail_timeout=0;
}
server {
listen 80;
client_max_body_size 4G;
keepalive_timeout 10;
error_page 500 502 504 /500.html;
error_page 503 #503;
server_name localhost rails-api.local;
root /home/deploy/apps/rails-api/current/public;
try_files $uri/index.html $uri #puma_rails-api_production;
location #puma_rails-api_production {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_pass http://puma_rails-api_production;
# limit_req zone=one;
access_log /home/deploy/apps/rails-api/shared/log/nginx.access.log;
error_log /home/deploy/apps/rails-api/shared/log/nginx.error.log;
}
location ^~ /assets/ {
gzip_static on;
expires max;
add_header Cache-Control public;
}
location = /50x.html {
root html;
}
location = /404.html {
root html;
}
location #503 {
error_page 405 = /system/maintenance.html;
if (-f $document_root/system/maintenance.html) {
rewrite ^(.*)$ /system/maintenance.html break;
}
rewrite ^(.*)$ /503.html break;
}
if ($request_method !~ ^(GET|HEAD|PUT|PATCH|POST|DELETE|OPTIONS)$ ){
return 405;
}
if (-f $document_root/system/maintenance.html) {
return 503;
}
location ~ \.(php|html)$ {
return 405;
}
}

Answer 1

Second error practically says that you have two server sections defined with listen 80 (which practically means 0.0.0.0:80 where 0.0.0.0 is equal to "any address") and localhost in server_name.
So, action you have to take depends on what you want to achieve:
Have some other app as default
If you want to have your app to be accessible alongside some other apps you have (or want to have in future) on server by some hostname, let's say example.com, you have to simply remove localhost from server_name in the entry you added.
In this case, you will have to access your app by one of the names you have specified for it in server_name ( example.com), neither localhost nor server IP.
Note that if you still have to make sure domain you've specified resolves to the server address.
If it is on your own local machine and you want to be able to access your app for development purposes (testing how it works with nginx, for example) you can
add row 127.0.0.1 name.here (for example, 127.0.0.1 example.com).
If it is on some server you own and you want others to be able to access app by the same domain, you have to buy/register it (if it has not been registered by someone else yet, it happens) and create the A DNS record pointing to your app server IP.
Make your app default
If you want this app to be default on the server, you can:
Find other server sections defined with listen 80 default; (so, if they don't have default or listen any other port like 8080 or 443 you can safely leave them) and remove the default from there - there can be only one default server section per port and IP combination.
Change listen 80; in your server section to listen 80 default;. This will tell nginx that you want this server section to handle all requests not catched by other section.
This will allow you to access app by IP and point any domain to it without specifying it in server_name section. You still need to register or buy domain to be able to point it to app.