Adding keepalive for nginx to better handle backend connections (#58)

* Updated with config for keepalive

* Updated to always enable keepalive

* Updated to always enable keepalive

* Updated minor chart version to 0.2.0

charts/ocp-proxy-api/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: ocp-proxy-api
 description: A Helm chart for Kubernetes to create and manage an nginx proxy for OCP API/Console
 type: application
-version: 0.1.3
+version: 0.2.0
 home: "https://rh-mobb.github.io/helm-charts/"
 maintainers:
   - name: rh-mobb

charts/ocp-proxy-api/templates/configmap.yaml

@@ -42,10 +42,11 @@ data:
         }
         upstream api_backend {
           server apiserver.openshift-kube-apiserver:443;
+          keepalive {{ .Values.keepalive.connections }};
         }
         upstream ingress_backend {
           server {{ .Values.ocp.ingressLB }}:443;
-
+          keepalive {{ .Values.keepalive.connections }};
         }
 
         server {
@@ -64,6 +65,15 @@ data:
             {{- end }}
 
             proxy_pass   $name;
+            
+            # Setting these keepalive parameters based on official docs.
+            # This avoids closing each connection and hence avoids exhausting the available resources
+            # https://nginx.org/en/docs/http/ngx_http_upstream_module.html#keepalive
+            #   and here:
+            # https://www.nginx.com/blog/avoiding-top-10-nginx-configuration-mistakes/#no-keepalives
+            proxy_http_version 1.1;
+            proxy_set_header Connection "";
+
             ssl_preread on;
         }
     }

charts/ocp-proxy-api/values.yaml

@@ -83,3 +83,8 @@ nodeSelector: {}
 tolerations: []
 
 affinity: {}
+
+keepalive:
+  # A good starting point for 'connections' is to set this to "(replicaCount * 2) + replicaCount"
+  # e.g.: (1 x 2) + 1 = 3
+  connections: 3