skip sorting upstream

ingress/controllers/nginx/configuration.md

@@ -264,6 +264,9 @@ Default is true
 **upstream-fail-timeout:** Sets the time during which the specified number of unsuccessful attempts to communicate with the [server](http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream) should happen to consider the server unavailable
 
 
+**upstream-skip-sort:** Setting this to 'true' stops the controller from sorting the upstreams by IP. This may help with unbalanced sticky sessions.
+
+
 **use-proxy-protocol:** Enables or disables the use of the [PROXY protocol](https://www.nginx.com/resources/admin-guide/proxy-protocol/) to receive client connection (real IP address) information passed through proxy servers and load balancers such as HAproxy and Amazon Elastic Load Balancer (ELB).
 
 

ingress/controllers/nginx/controller.go

@@ -777,7 +777,11 @@ func (lbc *loadBalancerController) getUpstreamServers(ngxCfg config.Configuratio
 			glog.Warningf("upstream %v does not have any active endpoints. Using default backend", value.Name)
 			value.Backends = append(value.Backends, nginx.NewDefaultServer())
 		}
-		sort.Sort(nginx.UpstreamServerByAddrPort(value.Backends))
+
+		if ngxCfg.UpstreamSkipSort != true {
+			sort.Sort(nginx.UpstreamServerByAddrPort(value.Backends))
+		}
+
 		aUpstreams = append(aUpstreams, value)
 	}
 	sort.Sort(nginx.UpstreamByNameServers(aUpstreams))

ingress/controllers/nginx/nginx/config/config.go

@@ -229,6 +229,12 @@ type Configuration struct {
 	// Default: 0, ie use platform liveness probe
 	UpstreamFailTimeout int `structs:"upstream-fail-timeout,omitempty"`
 
+	// Stops the controller from sorting the upstreams by ip address
+	// I suspect this will help with an issue in sticky sessions where the traffic is not
+	// evenly distributed.
+	// Default: false, sort the upstream
+	UpstreamSkipSort bool `structs:"upstream-skip-sort,omitempty"`
+
 	// Enables or disables the use of the PROXY protocol to receive client connection
 	// (real IP address) information passed through proxy servers and load balancers
 	// such as HAproxy and Amazon Elastic Load Balancer (ELB).