Rails + nginx + unicorn = 502 Bad Gateway

Question

Browser started showing 502 Bad Gateway - nginx suddenly. Below are my files

nginx/error.log

upstream sent too big header while reading response header from upstream

default.conf

upstream myapp_server {
  server myapp:4567 fail_timeout=0;
}

server {
  listen   80;
  server_name abcnow.com abcnow-demo.com abcsoon.com;

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

  return 301 https://$host$request_uri;
}

server {
  listen 443 default_server;
  server_name abcnow.com abcnow-demo.com abcsoon.com;

  access_log /dev/stdout;
  error_log stderr error;

  root /var/lib/www;

  ssl on;
  ssl_certificate /etc/ssl/certs/ops.pem;
  ssl_certificate_key /etc/ssl/private/ops-key.pem;

  ssl_session_timeout 5m;

  ssl_protocols SSLv3 TLSv1;
  ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
  ssl_prefer_server_ciphers on;

  try_files $uri/index.html $uri @myapp;

  location @myapp {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_set_header Forward-scheme https;
    proxy_redirect off;
    proxy_pass http://myapp_server;
  }
  client_max_body_size 4G;
  keepalive_timeout 10;

}

nginx.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

unicorn.rb

working_directory '/srv/www/myapp'
pid '/srv/www/tmp/myapp.pid'

stderr_path '/dev/stderr'
stdout_path '/dev/stdout'

listen 4567

worker_processes 11

timeout 300

I already tried adding the below to location , but still getting the error

proxy_buffer_size 128k; proxy_buffers 4 256k; proxy_busy_buffers_size 256k;

Answer 1

Try adding this!

large_client_header_buffers 4 512k;
client_max_body_size 25M;

proxy_buffer_size          512k;
proxy_buffers              4 1024k;
proxy_busy_buffers_size    1024k;