*: refine metrics (#1438)

.gitignore

@@ -14,3 +14,5 @@ relay_log/*
 vendor
 */*.DS_Store
 tidb-slow.log
+/monitoring/dashboards/dm.json
+/monitoring/rules/dm_worker.rules.yml

dm/dm-ansible/conf/dm_worker.rules.yml

@@ -1,6 +1,17 @@
 groups:
 - name: alert.rules
   rules:
+  - alert: DM_master_all_down
+    expr: up{job="dm_master"} == 0
+    labels:
+      env: ENV_LABELS_ENV
+      level: critical
+      expr: up{job="dm_master"} == 0
+    annotations:
+      description: 'cluster: ENV_LABELS_ENV, instance: {{ $labels.instance }}, values: {{ $value }}'
+      value: '{{ $value }}'
+      summary: DM master all down, metrics not relyable
+
   - alert: DM_remain_storage_of_relay_log
     expr: dm_relay_space{type="available"} < 10*1024*1024*1024
     labels:
@@ -126,12 +137,12 @@ groups:
       summary: dm syncer binlog file not catch up master server exceed 10 min
 
   - alert: DM_binlog_file_gap_between_relay_syncer
-    expr: dm_relay_binlog_file{node="relay"} - ON(instance, job) dm_syncer_binlog_file{node="syncer"} > 1
+    expr: dm_relay_binlog_file{node="relay"} - ON(instance, job) group_right dm_syncer_binlog_file{node="syncer"} > 1
     for: 10m
     labels:
       env: ENV_LABELS_ENV
       level: critical
-      expr: dm_relay_binlog_file{node="relay"} - ON(instance, job) dm_syncer_binlog_file{node="syncer"} > 1
+      expr: dm_relay_binlog_file{node="relay"} - ON(instance, job) group_right dm_syncer_binlog_file{node="syncer"} > 1
     annotations:
       description: 'cluster: ENV_LABELS_ENV, instance: {{ $labels.instance }}, task: {{ $labels.task }}, values: {{ $value }}'
       value: '{{ $value }}'

dm/master/metrics/metrics.go

@@ -15,12 +15,10 @@ package metrics
 
 import (
 	"context"
-	"net/http"
 	"time"
 
 	cpu "github.com/pingcap/tidb-tools/pkg/utils"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 
 	"github.com/pingcap/dm/pkg/metricsproxy"
 )
@@ -121,23 +119,14 @@ func RunBackgroundJob(ctx context.Context) {
 
 // RegistryMetrics registries metrics for worker
 func RegistryMetrics() {
-	registry := prometheus.NewRegistry()
-	registry.MustRegister(prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}))
-	registry.MustRegister(prometheus.NewGoCollector())
+	registry := prometheus.DefaultRegisterer
 
 	registry.MustRegister(workerState)
 	registry.MustRegister(cpuUsageGauge)
 	registry.MustRegister(ddlPendingCounter)
 	registry.MustRegister(ddlErrCounter)
 	registry.MustRegister(workerEventErrCounter)
 	registry.MustRegister(startLeaderCounter)
-
-	prometheus.DefaultGatherer = registry
-}
-
-// GetMetricsHandler returns prometheus HTTP Handler
-func GetMetricsHandler() http.Handler {
-	return promhttp.Handler()
 }
 
 // ReportWorkerStage is a setter for workerState

dm/master/server.go

@@ -179,18 +179,17 @@ func (s *Server) Start(ctx context.Context) (err error) {
 
 	registerOnce.Do(metrics.RegistryMetrics)
 
-	// HTTP handlers on etcd's client IP:port
+	// HTTP handlers on etcd's client IP:port. etcd will add a builtin `/metrics` route
 	// NOTE: after received any HTTP request from chrome browser,
 	// the server may be blocked when closing sometime.
 	// And any request to etcd's builtin handler has the same problem.
 	// And curl or safari browser does trigger this problem.
 	// But I haven't figured it out.
 	// (maybe more requests are sent from chrome or its extensions).
 	userHandles := map[string]http.Handler{
-		"/apis/":   apiHandler,
-		"/status":  getStatusHandle(),
-		"/debug/":  getDebugHandler(),
-		"/metrics": metrics.GetMetricsHandler(),
+		"/apis/":  apiHandler,
+		"/status": getStatusHandle(),
+		"/debug/": getDebugHandler(),
 	}
 
 	// gRPC API server