定制每一台Nginx服务的响应头，以便于当某台服务出现问题时能快速定位到具体的服务器

# cat nginx.conf.j2
user              nginx;
{# start process equal cpu cores #}
worker_processes {{ ansible_processor_vcpus }};

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;

    keepalive_timeout  0;

    gzip on;
    gzip_min_length  1k;
    gzip_buffers     8 64k;
    gzip_http_version 1.0;
    gzip_comp_level 5;
    gzip_types   text/plain application/x-javascript text/css application/json application/xml application/x-shockwave-flash application/javascript image/svg+xml image/x-icon;
    gzip_vary on;
    {# add_header {{ ansible_hostname }}; #}
    add_header x-hostname {{ ansible_hostname  }};

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