[Unit]
Description=gunicorn daemon
Requires=gunicorn.socket
After=network.target

[Service]
PIDFile=/run/gunicorn/pid
User=root
Group=root
RuntimeDirectory=gunicorn
WorkingDirectory=/srv/myproject/current
ExecStart=/srv/venvs/myenv/bin/gunicorn --pid /run/gunicorn/pid
          --bind unix:/run/gunicorn/gunicorn.socket myapp.wsgi:application
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID
PrivateTmp=true

[Install]
WantedBy=multi-user.target

gunicorn.service - gunicorn daemon
   Loaded: loaded (/etc/systemd/system/gunicorn.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2018-01-18 23:08:49 UTC; 3min 41s ago
  Process: 5852 ExecStop=/bin/kill -s TERM $MAINPID (code=exited, status=0/SUCCESS)
 Main PID: 5858 (gunicorn)
    Tasks: 2
   Memory: 195.7M
      CPU: 1.426s
   CGroup: /system.slice/gunicorn.service
           ├─5858 /srv/venvs/myenv/bin/python3.6 /srv/venvs/myenv/bin/gunicorn --pid /run/gunicorn/pid --bind unix:/run/gunicorn/gunicorn.socket myapp.wsgi:application
           └─5862 /srv/venvs/myenv/bin/python3.6 /srv/venvs/myenv/bin/gunicorn --pid /run/gunicorn/pid --bind unix:/run/gunicorn/gunicorn.socket myapp.wsgi:application

Jan 18 23:08:49 python-server systemd[1]: Started gunicorn daemon.
Jan 18 23:08:49 python-server gunicorn[5858]: [2018-01-18 23:08:49 +0000] [5858] [INFO] Starting gunicorn 19.7.1
Jan 18 23:08:49 python-server gunicorn[5858]: [2018-01-18 23:08:49 +0000] [5858] [INFO] Listening at: unix:/run/gunicorn/socket (5858)
Jan 18 23:08:49 python-server gunicorn[5858]: [2018-01-18 23:08:49 +0000] [5858] [INFO] Using worker: sync
Jan 18 23:08:49 python-server gunicorn[5858]: [2018-01-18 23:08:49 +0000] [5862] [INFO] Booting worker with pid: 5862

server {
    server_tokens off;
    listen      443 ssl;
    server_name         myserver.com;
    keepalive_timeout   70;

    ssl_certificate     /etc/ssl/certs/myserver.com.merged.crt;
    ssl_certificate_key /etc/ssl/private/myserver.com.key;

    ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers         HIGH:!aNULL:!MD5;

    #access_log      /var/log/nginx/access.myserver.log;
    access_log      /var/log/nginx/access.myserver.log;
    #error_log       /var/log/nginx/error.myserver.log;
    error_log       /var/log/nginx/error.myserver.log;

    location / {
        include proxy_params;
        proxy_pass http://unix:/run/gunicorn/gunicorn.socket;
    }
}

2018/01/18 23:09:00 [crit] 5764#5764: *4 connect() to unix:/run/gunicorn/gunicorn.socket failed (2: No such file or directory) while connecting to upstream, client: 212.251.167.250, server: myserver.com, request: "GET / HTTP/1.1", upstream: "http://unix:/run/gunicorn/gunicorn.socket:/", host: "myserver.com"