Nginx 502 when running Rails (Puma) with -d (daemon) - ruby-on-rails

Question

Ruby 2.5.1, Rails 5.2.2.1
I'm trying to make nginx get upstream through puma socket.
When I run rails s -e production all is good.
When I run rails s -e production -d Nginx returns 502 Bad Gateway
config/puma.rb
...
app_dir = "/home/user/myapp"
tmp_dir = "#{app_dir}/tmp"
# Set up socket location
bind "unix://#{tmp_dir}/sockets/puma.sock"
# Logging
stdout_redirect "#{app_dir}/log/puma.stdout.log", "#{app_dir}/log/puma.stderr.log", true
...
etc/nginx/sites-enabled/mydomain.com
upstream app {
# Path to Puma SOCK file, as defined previously
server unix:/home/user/myapp/tmp/sockets/puma.sock fail_timeout=0;
}
server {
listen 80;
server_name mydomain.com;
root /home/user/myapp/public;
try_files $uri/index.html $uri #app;
location #app {
proxy_pass http://app;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
}
error_page 500 502 503 504 /500.html;
client_max_body_size 4G;
keepalive_timeout 10;
}
var/log/nginx/error.log
2019/07/07 13:45:09 [error] 21609#21609: *11391 connect() to
unix:/home/user/myapp/tmp/sockets/puma.sock failed (111: Connection
refused) while connecting to upstream, client: 172.68.11.91, server:
mydomain.com, request: "GET /pages/one HTTP/1.1", upstream:
"http://unix:/home/user/myapp/tmp/sockets/puma.sock:/pages/one", host: "mydomain.com"
(P.S. change from original domain to mydomain.com)
What difference? How to fix it? Please explain and help
UPDATE
Seems to be running with daemon flag it doesn't create puma.sock in /home/user/myapp/tmp/sockets. Why and where is it?

Answer 1

The earlier answer does not work any more. The deamon option -d is deprecated.
You could use a systemd service:
sudo nano /etc/systemd/system/puma.service
Copy this to the file and fill in your YOUR_APP_PATH and FULLPATH:
[Unit]
Description=Puma HTTP Server
After=network.target
# Uncomment for socket activation (see below)
# Requires=puma.socket
[Service]
# Puma supports systemd's `Type=notify` and watchdog service
# monitoring, if the [sd_notify](https://github.com/agis/ruby-sdnotify) gem is installed,
# as of Puma 5.1 or later.
# On earlier versions of Puma or JRuby, change this to `Type=simple` and remove
# the `WatchdogSec` line.
Type=notify
# If your Puma process locks up, systemd's watchdog will restart it within seconds.
WatchdogSec=10
# Preferably configure a non-privileged user
# User=
# The path to your application code root directory.
# Also replace the "<YOUR_APP_PATH>" placeholders below with this path.
# Example /home/username/myapp
WorkingDirectory=<YOUR_APP_PATH>
# Helpful for debugging socket activation, etc.
# Environment=PUMA_DEBUG=1
# SystemD will not run puma even if it is in your path. You must specify
# an absolute URL to puma. For example /usr/local/bin/puma
# Alternatively, create a binstub with `bundle binstubs puma --path ./sbin` in the WorkingDirectory
ExecStart=/<FULLPATH>/bin/puma -C <YOUR_APP_PATH>/puma.rb
# Variant: Rails start.
# ExecStart=/<FULLPATH>/bin/puma -C <YOUR_APP_PATH>/config/puma.rb ../config.ru
# Variant: Use `bundle exec --keep-file-descriptors puma` instead of binstub
# Variant: Specify directives inline.
# ExecStart=/<FULLPATH>/puma -b tcp://0.0.0.0:9292 -b ssl://0.0.0.0:9293?key=key.pem&cert=cert.pem
Restart=always
[Install]
WantedBy=multi-user.target
Run systemctl daemon-reload to reload your services.
Then you can use sudo systemctl restart puma to restart/start/stop the service
Refer to the puma docs for more information.

Answer 2

Solution
Dont know why, but It works if run puma (not rails server)
RAILS_ENV=production bundle exec puma -C config/puma.rb -d