Antrea Prometheus integration (antrea-io#236)

Integrate with Prometheus monitoring solution.
Integration of the Prometheus client into Antrea controller and agent
allows the exposure of various metrics to Prometheus server.
In addition to Antrea's own set of metrics, Prometheus client will also
expose metrics which are defined by various components which are part of
the Antrea ecosystem, e.g golang, Prometheus itself etc.

build/yamls/antrea-ipsec.yml

@@ -281,6 +281,21 @@ data:
     #          Underlying network must be capable of supporting Pod traffic across IP subnet.
     # hybrid: noEncap if worker Nodes on same subnet, otherwise encap.
     #trafficEncapMode: encap
+
+    # Enable metrics exposure via Prometheus. Initializes Prometheus metrics listener
+    #enablePrometheusMetrics: false
+
+    # Enable golang metrics exposure via Prometheus
+    #enablePrometheusGoMetrics: false
+
+    # Enable process metrics exposure via Prometheus.
+    #enablePrometheusProcessMetrics: false
+
+    # Prometheus metrics hostname.
+    #prometheusHost:
+
+    # Prometheus listener port.
+    #prometheusPort: 9092
   antrea-cni.conf: |
     {
         "cniVersion":"0.3.0",
@@ -290,7 +305,21 @@ data:
             "type": "host-local"
         }
     }
-  antrea-controller.conf: ""
+  antrea-controller.conf: |
+    # Enable metrics exposure via Prometheus. Initializes Prometheus metrics listener
+    #enablePrometheusMetrics: false
+
+    # Enable golang metrics exposure via Prometheus
+    #enablePrometheusGoMetrics: false
+
+    # Enable process metrics exposure via Prometheus.
+    #enablePrometheusProcessMetrics: false
+
+    # Prometheus metrics hostname.
+    #prometheusHost:
+
+    # Prometheus listener port.
+    #prometheusPort: 9093
 kind: ConfigMap
 metadata:
   annotations: {}
@@ -320,6 +349,9 @@ spec:
   - port: 443
     protocol: TCP
     targetPort: 443
+  - port: 9093
+    protocol: TCP
+    targetPort: 9093
   selector:
     app: antrea
     component: antrea-controller
@@ -371,6 +403,8 @@ spec:
         ports:
         - containerPort: 443
           protocol: TCP
+        - containerPort: 9093
+          protocol: TCP
         readinessProbe:
           failureThreshold: 5
           httpGet:
@@ -510,6 +544,10 @@ spec:
           initialDelaySeconds: 5
           periodSeconds: 10
           timeoutSeconds: 5
+        ports:
+        - containerPort: 9092
+          hostPort: 9092
+          protocol: TCP
         securityContext:
           privileged: true
         volumeMounts:

cmd/antrea-controller/options.go

@@ -24,7 +24,7 @@ import (
 )
 
 const (
-	defaultPrometheusPort     = 9093
+	defaultPrometheusPort = 9093
 )
 
 type Options struct {

pkg/agent/metrics/prometheus.go

@@ -29,7 +29,7 @@ import (
 )
 
 type OVSStatManager struct {
-	ofClient openflow.Client
+	ofClient     openflow.Client
 	OVSBridge    string
 	OVSTableDesc *prometheus.Desc
 }
@@ -38,7 +38,7 @@ func (c *OVSStatManager) OVSGetStatistics() (
 	ovsFlowsByTable map[string]float64,
 ) {
 	ovsFlowsByTable = make(map[string]float64)
-	flowTableStatus :=c.ofClient.GetFlowTableStatus()
+	flowTableStatus := c.ofClient.GetFlowTableStatus()
 	for _, tableStatus := range flowTableStatus {
 		ovsFlowsByTable[strconv.Itoa(int(tableStatus.ID))] = float64(tableStatus.FlowCount)
 	}
@@ -84,7 +84,7 @@ func StartListener(
 	ofClient openflow.Client) {
 	hostname, err := os.Hostname()
 	if err != nil {
-		klog.Error("Failed to retrieve agent node name, %v", err)
+		klog.Errorf("Failed to retrieve agent node name, %v", err)
 	}
 	klog.Info("Binding antrea_local_pod_count")
 	if err := prometheus.Register(prometheus.NewGaugeFunc(