nginx.conf

# One worker process per CPU core.
worker_processes 8;

# Also set
# /etc/security/limits.conf
#   web soft nofile 65535
#   web hard nofile 65535
# /etc/default/nginx
#       ULIMIT="-n 65535"
worker_rlimit_nofile 65535;

pid /run/nginx.pid;

events {
    #
    # Determines how many clients will be served by each worker process.
    # (Max clients = worker_connections * worker_processes)
    # Should be equal to `ulimit -n / worker_processes`
    #
    worker_connections 65535;

    #
    # Let each process accept multiple connections.
    # Accept as many connections as possible, after nginx gets notification
    # about a new connection.
    # May flood worker_connections, if that option is set too low.
    #
    multi_accept on;

    #
    # Preferred connection method for newer linux versions.
    # Essential for linux, optmized to serve many clients with each thread.
    #
    use epoll;
}

http {

    ##
    # Basic Settings
    ##

    #
    # Override some buffer limitations, will prevent DDOS too.
    #
    client_body_buffer_size 10K;
    client_header_buffer_size 1k;
    client_max_body_size 8m;
    large_client_header_buffers 2 1k;

    client_body_timeout   32;
    client_header_timeout 32;

    keepalive_timeout 90; # default 65
    send_timeout 120;     # default 60

    reset_timedout_connection on;

    #
    # Open file descriptors.
    # Caches information about open FDs, freqently accessed files.
    #
    open_file_cache max=200000 inactive=20s;
    open_file_cache_valid 30s;
    open_file_cache_min_uses 2;
    open_file_cache_errors on;

    sendfile on;


    types_hash_max_size 2048;

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

    ##
    # Logging Settings
    ##

    #
    # Use analytics to track stuff instead of using precious file IO resources.
    # Disabling logging speeds up IO.
    #
    access_log off;
    error_log off;

    ##
    # Gzip Settings
    ##

    gzip on;
    gzip_disable "MSIE [1-6]\.";

    # Only allow proxy request with these headers to be gzipped.
    gzip_proxied expired no-cache no-store private auth;

    # Default is 6 (1<n<9), but 2 -- even 1 -- is enough. The higher it is, the
    # more CPU cycles will be wasted.
    gzip_comp_level 3;
    gzip_min_length 20; # Default 20

    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    ##
    # Virtual Host Configs
    ##

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

    upstream api {
        server api01:9999;
        server api02:9999;
    }

    server {
        listen 9999;
        
        location / {
            proxy_pass http://api;
        }
    }
}