introduce elasticsearch index name

Signed-off-by: ZhangJian He <shoothzj@gmail.com>

docs/design/usage-based-scheduling.md

@@ -60,6 +60,8 @@ metrics:                             # metrics server related configuration
   type: prometheus                   # Optional, The metrics source type, prometheus by default, support prometheus and elasticsearch
   address: http://192.168.0.10:9090  # mandatory, The metrics source address
   interval: 30s                      # Optional, The scheduler pull metrics from Prometheus with this interval, 5s by default
+  elasticsearch:                     # Optional, The elasticsearch configuration
+    index: "custom-index-name"       # Optional, The elasticsearch index name, "metricbeat-*" by default
   ```
 
 ### How to predicate node

pkg/scheduler/metrics/source/metrics_client.go

@@ -37,7 +37,7 @@ func NewMetricsClient(metricsConf map[string]string) (MetricsClient, error) {
 	}
 	metricsType := metricsConf["type"]
 	if metricsType == "elasticsearch" {
-		return NewElasticsearchMetricsClient(address)
+		return NewElasticsearchMetricsClient(address, metricsConf)
 	}
 	return &PrometheusMetricsClient{address: address}, nil
 }

pkg/scheduler/metrics/source/metrics_client_elasticsearch.go

@@ -33,12 +33,19 @@ const (
 )
 
 type ElasticsearchMetricsClient struct {
-	address string
-	es      *elasticsearch.Client
+	address   string
+	indexName string
+	es        *elasticsearch.Client
 }
 
-func NewElasticsearchMetricsClient(address string) (*ElasticsearchMetricsClient, error) {
+func NewElasticsearchMetricsClient(address string, conf map[string]string) (*ElasticsearchMetricsClient, error) {
 	e := &ElasticsearchMetricsClient{address: address}
+	indexConf := conf["elasticsearch.index"]
+	if len(indexConf) == 0 {
+		e.indexName = "metricbeat-*"
+	} else {
+		e.indexName = indexConf
+	}
 	var err error
 	e.es, err = elasticsearch.NewDefaultClient()
 	if err != nil {