Upgrade prometheus image to v2.19.3

- Make e2e prometheus test consistent by querying target metadata API

Signed-off-by: Yuki Tsuboi <ytsuboi@vmware.com>

build/yamls/antrea-prometheus.yml

@@ -122,7 +122,7 @@ spec:
     spec:
       containers:
         - name: prometheus
-          image: prom/prometheus:v2.2.1
+          image: prom/prometheus:v2.19.3
           args:
             - "--config.file=/etc/prometheus/prometheus.yml"
             - "--storage.tsdb.path=/prometheus/"

docs/prometheus-integration.md

@@ -21,6 +21,9 @@ Enable Prometheus metrics listener by setting `enablePrometheusMetrics`
 parameter to true in the Controller and the Agent configurations.
 
 ## Prometheus Configuration
+
+### Prometheus version
+Prometheus integration with Antrea is validated as part of CI using Prometheus v2.19.3.
 
 ### Prometheus RBAC
 Prometheus requires access to Kubernetes API resources for the service discovery

test/e2e/prometheus_test.go

@@ -66,7 +66,9 @@ var prometheusEnabled bool
 // Prometheus server JSON output
 type prometheusServerOutput struct {
 	Status string
-	Data   []map[string]string
+	Data   []struct {
+		Metric string
+	}
 }
 
 func init() {
@@ -255,8 +257,10 @@ func testMetricsFromPrometheusServer(t *testing.T, data *TestData, prometheusJob
 	hostIP, nodePort := getPrometheusEndpoint(t, data)
 
 	// Build the Prometheus query URL
-	path := url.PathEscape("match[]={job=\"" + prometheusJob + "\"}")
-	queryUrl := fmt.Sprintf("http://%s:%d/api/v1/series?%s", hostIP, nodePort, path)
+	// Target metadata API(/api/v1/targets/metadata) has been available since Prometheus v2.4.0.
+	// This API is still experimental in Prometheus v2.19.3.
+	path := url.PathEscape("match_target={job=\"" + prometheusJob + "\"}")
+	queryUrl := fmt.Sprintf("http://%s:%d/api/v1/targets/metadata?%s", hostIP, nodePort, path)
 
 	client := &http.Client{}
 	resp, err := client.Get(queryUrl)
@@ -280,8 +284,7 @@ func testMetricsFromPrometheusServer(t *testing.T, data *TestData, prometheusJob
 	// Create a map of all the metrics which were found on the server
 	testMap := make(map[string]bool)
 	for _, metric := range output.Data {
-		name := strings.TrimSuffix(metric["__name__"], "_bucket")
-		testMap[name] = true
+		testMap[metric.Metric] = true
 	}
 
 	// Validate that all the required metrics exist in the server's output