title: How to solve nginx - no live upstreams while connecting to upstream client?
body: <p>Currently I am running a load test using JMeter on our system build on grails 3 running on tomcat. After sending 20k request per second I got “no live upstreams while connecting to upstream client” in nginx error log. Our application is multi-tenant base so I need to perform high load.  Here is my nginx configuration. </p>
  
  <pre><code>worker_processes  16;
  worker_rlimit_nofile 262144;
  error_log  /var/log/nginx/error.log;
  
  events {
      worker_connections  24576;
      use epoll;
      multi_accept on;
  }
  
  
  http {
      include       mime.types;
      default_type  application/octet-stream;
  
      sendfile        on;
      keepalive_timeout  600;
      keepalive_requests 100000;
      access_log off;
      server_names_hash_max_size  4096;
      underscores_in_headers  on;
      client_max_body_size 8192m;
      log_format vhost '$remote_addr - $remote_user [$time_local] $status "$request" $body_bytes_sent "$http_referer" "$http_user_agent" "http_x_forwarded_for"';
  
      proxy_connect_timeout      120;
      proxy_send_timeout         120;
      proxy_read_timeout         120;
  
  
      gzip  on;
      gzip_types text/plain application/xml text/css text/js text/xml application/x-javascript text/javascript application/json application/xml+rss image application/javascript;
      gzip_min_length  1000;
      gzip_static on;
      gzip_vary on;
      gzip_buffers 16 8k;
      gzip_comp_level 6;
      gzip_proxied any;
      gzip_disable "msie6";
  
      proxy_intercept_errors on;
      recursive_error_pages on;
  
      ssl_prefer_server_ciphers On;
      ssl_ciphers ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-RC4-SHA:ECDHE-RSA-AES256-SHA:RC4-SHA;
      include /etc/nginx/conf.d/*.conf;
  }
  </code></pre>
  
  <p>How do I configure for high concurrent load?</p>