linkerd metrics: Add ServiceMonitor for control plane

- Adds ServiceMonitors to monitor linkerd control plane pods.

- Adds entry in the components prometheus metrics list to test if the
linkerd metrics are being scraped.

Signed-off-by: Suraj Deshmukh <suraj@kinvolk.io>

assets/charts/components/linkerd2/templates/service-monitors.yaml

@@ -0,0 +1,123 @@
+{{ if .Values.enableMonitoring }}
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-web
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: web
+  endpoints:
+  - targetPort: 9994
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-sp-validator
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: sp-validator
+  endpoints:
+  - targetPort: 9997
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-controller-api
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: controller
+  endpoints:
+  - targetPort: 9995
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-identity
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: identity
+  endpoints:
+  - targetPort: 9990
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-proxy-injector
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: proxy-injector
+  endpoints:
+  - targetPort: 9995
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-tap
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: tap
+  endpoints:
+  - targetPort: 9998
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-dst
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-component: destination
+  endpoints:
+  - targetPort: 9996
+---
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  labels:
+    app: linkerd
+    release: prometheus-operator
+  name: linkerd-proxies
+  namespace: {{.Values.global.namespace}}
+spec:
+  selector:
+    matchLabels:
+      linkerd.io/control-plane-ns: linkerd
+  endpoints:
+  - targetPort: 4191
+---
+{{end}}

ci/aws/aws-cluster.lokocfg.envsubst

@@ -127,7 +127,9 @@ component "prometheus-operator" {
   }
 }
 
-component "experimental-linkerd" {}
+component "experimental-linkerd" {
+  enable_monitoring   = true
+}
 
 component "contour" {
   enable_monitoring = true

ci/packet/packet-cluster.lokocfg.envsubst

@@ -85,6 +85,7 @@ component "prometheus-operator" {
 
 component "experimental-linkerd" {
   controller_replicas = 2
+  enable_monitoring   = true
 }
 
 component "contour" {

pkg/components/linkerd/component.go

@@ -40,7 +40,8 @@ func init() {
 }
 
 type component struct {
-	ControllerReplicas int `hcl:"controller_replicas,optional"`
+	ControllerReplicas int  `hcl:"controller_replicas,optional"`
+	EnableMonitoring   bool `hcl:"enable_monitoring,optional"`
 
 	Cert cert
 }
@@ -55,6 +56,7 @@ type cert struct {
 func newComponent() *component {
 	return &component{
 		ControllerReplicas: 1,
+		EnableMonitoring:   false,
 	}
 }
 

pkg/components/linkerd/manifest.go

@@ -16,6 +16,7 @@
 package linkerd
 
 const chartValuesTmpl = `
+enableMonitoring: {{.EnableMonitoring}}
 global:
   identityTrustAnchorsPEM: |
 {{ .Cert.CA }}

test/monitoring/components_metrics_test.go

@@ -90,6 +90,11 @@ func testComponentsPrometheusMetrics(t *testing.T, v1api v1.API) {
 			query:         "certmanager_controller_sync_call_count",
 			platforms:     []testutil.Platform{testutil.PlatformPacket, testutil.PlatformAWS, testutil.PlatformAKS},
 		},
+		{
+			componentName: "linkerd",
+			query:         "tcp_read_bytes_total",
+			platforms:     []testutil.Platform{testutil.PlatformPacket, testutil.PlatformAWS},
+		},
 	}
 
 	for _, tc := range testCases {