MINOR: add setting for channels size

Setting the channel size has direct effect in performance in crowded cluster. Too many resources implies a delay in readiness, a general slowdown and even a skip of event if the channel gets full.

Author: ivanmatmati

controller/controller.go

@@ -117,11 +117,16 @@ func (c *HAProxyController) Start() {
 	}
 
 	// Monitor k8s events
-	c.eventChan = make(chan SyncDataEvent, watch.DefaultChanSize*6)
+	var chanSize int64 = int64(watch.DefaultChanSize * 6)
+	if c.OSArgs.ChannelSize > 0 {
+		chanSize = c.OSArgs.ChannelSize
+	}
+	logger.Infof("Channel size: %d", chanSize)
+	c.eventChan = make(chan SyncDataEvent, chanSize)
 	go c.monitorChanges()
 	if c.PublishService != nil {
 		// Update Ingress status
-		c.ingressChan = make(chan ingress.Sync, watch.DefaultChanSize*6)
+		c.ingressChan = make(chan ingress.Sync, chanSize)
 		go ingress.UpdateStatus(c.k8s.API, c.Store, c.OSArgs.IngressClass, c.OSArgs.EmptyIngressClass, c.ingressChan)
 	}
 }

controller/utils/flags.go

@@ -100,4 +100,5 @@ type OSArgs struct { //nolint:maligned
 	DisableServiceExternalName bool           `long:"disable-service-external-name" description:"disable forwarding to ExternalName Services due to CVE-2021-25740"`
 	UseWiths6Overlay           bool           `long:"with-s6-overlay" description:"use s6 overlay to start/stpop/reload HAProxy"`
 	PromotheusPort             int64          `long:"enable-prometheus-port" description:"port to listen on for Prometheus metrics"`
+	ChannelSize                int64          `long:"channel-size" description:"sets the size of controller buffers used to receive and send k8s events.NOTE: increase the value to accommodate large number of resources "`
 }

documentation/controller.md

@@ -36,6 +36,7 @@ Image can be run with arguments:
 | [`--config-dir`](#--config-dir) | `/tmp/haproxy-ingress/etc` |
 | [`--runtime-dir`](#--runtime-dir) | `/tmp/haproxy-ingress/run` |
 | [`--disable-service-external-name`](#--disable-service-external-name) | `false` |
+| [`--channel-size`](#--channel-size) | `600` |
 
 
 ### `--configmap`
@@ -654,3 +655,24 @@ args:
 
 ***
 
+### `--channel-size`
+
+  Sets the size of controller buffers used to receive and send k8s events.
+This parameter is a cursor to adapt to the number of resources inside your clusters and that generate a lot of events.
+Rule of thumb: the more resources the higher the value.
+
+Possible values:
+
+- Size of channels used for k8s resources events with regards to ingresses, etc.
+
+Example:
+
+```yaml
+args:
+  - --channel-size=10000
+```
+
+<p align='right'><a href='#haproxy-kubernetes-ingress-controller'>:arrow_up_small: back to top</a></p>
+
+***
+

documentation/doc.yaml

@@ -382,6 +382,18 @@ image_arguments:
     helm: |-
       helm install haproxy haproxytech/kubernetes-ingress \
         --set-string "controller.extraArgs={--disable-service-external-name}"
+  - argument: --channel-size
+    description: |-
+      Sets the size of controller buffers used to receive and send k8s events.
+      This parameter is a cursor to adapt to the number of resources inside your clusters and that generate a lot of events.
+      Rule of thumb: the more resources the higher the value.
+    values:
+      - Size of channels used for k8s resources events with regards to ingresses, etc.
+    default: 600
+    version_min: "1.7"
+    example: |-
+      args:
+        - --channel-size=10000
 groups:
   config-snippet:
     header: |-