Nginx, Varnish, HAProxy, and Thin/Lighttpd

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;
    log_format main '$remote_addr - $remote_user [$time_local] $request "$status" $body_bytes_sent "$http_referer" "$http_user_agent" "$http_x_forwarded_for"';
    sendfile on;
    tcp_nopush on;
    tcp_nodelay off;
    keepalive_timeout 5;

    # This section enables gzip compression.
    gzip on;
    gzip_comp_level 2;
    gzip_proxied any;
    gzip_types text/plain text/html text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    # Here you can define the addresses on which varnish will listen. You can place multiple servers here, and nginx will load balance between them.
    upstream cache_servers {
      server localhost:6081 max_fails=3 fail_timeout=30s;
    }

    # This is the default virtual host.
    server {
        listen 80 default;
        access_log /var/log/nginx/access.log main;
        error_log /var/log/nginx/error.log;
        charset utf-8;

        # This is optional. It serves up a 1x1 blank gif image from RAM.
        location = /1x1.gif {
          empty_gif;
        }

        # This is the actual part which will proxy all connections to varnish.
        location / {
          proxy_pass http://cache_servers/;
          proxy_redirect http://cache_servers/ http://$host:$server_port/;
          proxy_set_header Host $host;
          proxy_set_header X-Real-IP $remote_addr;
          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }
    }
}

DAEMON_OPTS="-a localhost:6081 \
             -T localhost:6082 \
             -f /etc/varnish/default.vcl \
             -u varnish -g varnish \
             -s file,/var/lib/varnish/varnish_storage.bin,10G"`

backend thin {
  .host = "127.0.0.1";
  .port = "8080";
}

backend lighttpd {
  .host = "127.0.0.1";
  .port = "8081";
}

sub vcl_recv {
    if (req.url ~ "^/static/") {
        set req.backend = lighttpd;
    } else {
        set req.backend = thin;
    }

    # Allow purging of cache using shift + reload
    if (req.http.Cache-Control ~ "no-cache") {
        purge_url(req.url);
    }

    # Unset any cookies and autorization data for static links and icons, and fetch from catch
    if (req.request == "GET" && req.url ~ "^/static/" || req.request == "GET" && req.url ~ "^/icons/") {
        unset req.http.cookie;
        unset req.http.Authorization;
        lookup;
    }

    # Look for images in the cache
    if (req.url ~ "\.(png|gif|jpg|ico|jpeg|swf|css|js)$") {
        unset req.http.cookie;
        lookup;
    }

    # Do not cache any POST'ed data
    if (req.request == "POST") {
        pass;
    }

    # Do not cache any non-standard requests
    if (req.request != "GET" && req.request != "HEAD" &&
        req.request != "PUT" && req.request != "POST" &&
        req.request != "TRACE" && req.request != "OPTIONS" &&
        req.request != "DELETE") {
        pass;
    }

    # Do not cache data which has an autorization header
    if (req.http.Authorization) {
        pass;
    }

    lookup;
}

sub vcl_fetch {
    # Remove cookies and cache static content for 12 hours
    if (req.request == "GET" && req.url ~ "^/static/" || req.request == "GET" && req.url ~ "^/icons/") {
        unset obj.http.Set-Cookie;
        set obj.ttl = 12h;
        deliver;
    }

    # Remove cookies and cache images for 12 hours
    if (req.url ~ "\.(png|gif|jpg|ico|jpeg|swf|css|js)$") {
        unset obj.http.set-cookie;
        set obj.ttl = 12h;
        deliver;
    }

    # Do not cache anything that does not return a value in the 200's
    if (obj.status >= 300) {
        pass;
    }

    # Do not cache content which varnish has marked uncachable
    if (!obj.cacheable) {
        pass;
    }

    # Do not cache content which has a cookie set
    if (obj.http.Set-Cookie) {
        pass;
    }

    # Do not cache content with cache control headers set
    if (obj.http.Pragma ~ "no-cache" || obj.http.Cache-Control ~ "no-cache" || obj.http.Cache-Control ~ "private") {
        pass;
    }

    if (obj.http.Cache-Control ~ "max-age") {
        unset obj.http.Set-Cookie;
        deliver;
    }

    pass;
}

global
  daemon
  log 127.0.0.1 local0
  maxconn 4096
  nbproc 1
  chroot /var/lib/haproxy
  user haproxy
  group haproxy

defaults
  mode http
  clitimeout 60000
  srvtimeout 30000
  timeout connect 4000
  option httpclose
  option abortonclose
  option httpchk
  option forwardfor
  balance roundrobin
  stats enable
  stats refresh 5s
  stats auth admin:123abc789xyz

listen thin 127.0.0.1:8080
  server thin 10.10.10.2:2010 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2011 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2012 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2013 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2014 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2015 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2016 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2017 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2018 weight 1 minconn 3 maxconn 6 check inter 20000
  server thin 10.10.10.2:2019 weight 1 minconn 3 maxconn 6 check inter 20000

server.port = 8081
server.bind = "127.0.0.1"