🥇Prometheus: nadzor HTTP preko Blackbox ekspanterja

Pozdrav svima. U maju OTUS pokreće praktični rad na monitoringu i logovanju, kako infrastrukture tako i aplikacija uz pomoć Zabbix-a, Prometheus-a, Grafana-e i ELK-a. U tom smislu, tradicionalno delimo korisne materijale na ovu temu.

Blackbox eksportor za Prometheus omogućava implementaciju monitoringa spoljnih servisa putem HTTP, HTTPS, DNS, TCP i ICMP. U ovom članku ću vam pokazati kako da postavite monitoring HTTP/HTTPS pomoću Blackbox eksportora. Pokrećemo Blackbox eksportor u Kubernetes-u.

Okolje

Biće nam potrebno sledeće:

Kubernetes
Prometheus Operator

Konfiguracija blackbox eksportora

Konfigurišemo Blackbox putem ConfigMap za podešavanje http modula za monitoring web servisa.

apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
data:
  blackbox.yaml: |
    modules:
      http_2xx:
        http:
          no_follow_redirects: false
          preferred_ip_protocol: ip4
          valid_http_versions:
          - HTTP/1.1
          - HTTP/2
          valid_status_codes: []
        prober: http
        timeout: 5s

Modul http_2xx koristi se za proveru da li web servis vraća HTTP status kod 2xx. Detaljnije informacije o konfiguraciji blackbox eksportora su opisane u dokumenti.

Deploy blackbox eksportora u Kubernetes klaster

Definišite Deployment in Storitev za raspoređivanje u Kubernetes.

---
kind: Service
apiVersion: v1
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
spec:
  type: ClusterIP
  ports:
    - name: http
      port: 9115
      protocol: TCP
  selector:
    app: prometheus-blackbox-exporter

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: prometheus-blackbox-exporter
  labels:
    app: prometheus-blackbox-exporter
spec:
  replicas: 1
  selector:
    matchLabels:
      app: prometheus-blackbox-exporter
  template:
    metadata:
      labels:
        app: prometheus-blackbox-exporter
    spec:
      restartPolicy: Always
      containers:
        - name: blackbox-exporter
          image: "prom/blackbox-exporter:v0.15.1"
          imagePullPolicy: IfNotPresent
          securityContext:
            readOnlyRootFilesystem: true
            runAsNonRoot: true
            runAsUser: 1000
          args:
            - "--config.file=/config/blackbox.yaml"
          resources:
            {}
          ports:
            - containerPort: 9115
              name: http
          livenessProbe:
            httpGet:
              path: /health
              port: http
          readinessProbe:
            httpGet:
              path: /health
              port: http
          volumeMounts:
            - mountPath: /config
              name: config
        - name: configmap-reload
          image: "jimmidyson/configmap-reload:v0.2.2"
          imagePullPolicy: "IfNotPresent"
          securityContext:
            runAsNonRoot: true
            runAsUser: 65534
          args:
            - --volume-dir=/etc/config
            - --webhook-url=http://localhost:9115/-/reload
          resources:
            {}
          volumeMounts:
            - mountPath: /etc/config
              name: config
              readOnly: true
      volumes:
        - name: config
          configMap:
            name: prometheus-blackbox-exporter

Blackbox eksportor se može rasporediti pomoću sledeće komande. Ime prostora monitoring se odnosi na Prometheus Operator.

kubectl --namespace=monitoring apply -f blackbox-exporter.yaml

Prepričajte se, da so vse storitve zagnane z uporabo naslednjega ukaza:

kubectl --namespace=monitoring get all --selector=app=prometheus-blackbox-exporter

Preverjanje Blackbox

Dostopate lahko do spletnega vmesnika Blackbox izvoznika preko port-forward:

kubectl --namespace=monitoring port-forward svc/prometheus-blackbox-exporter 9115:9115

Povežite se z spletni vmesnikom Blackbox izvoznika preko spletnega brskalnika na naslovu localhost:9115.

Če odprete povezavo http://localhost:9115/probe?module=http_2xx&target=https://www.google.com, boste videli rezultat preverjanja navedenega URL-ja (https://www.google.com).

Vrednost metrike probe_success enaka 1 pomeni uspešno preverjanje. Vrednost 0 pomeni napako.

Nastavitev Prometheus

Po namestitvi BlackBox izvoznika nastavimo Prometheus v prometheus-additional.yaml.

- job_name: 'kube-api-blackbox'
  scrape_interval: 1w
  metrics_path: /probe
  params:
    module: [http_2xx]
  static_configs:
   - targets:
      - https://www.google.com
      - http://www.example.com
      - https://prometheus.io
  relabel_configs:
   - source_labels: [__address__]
     target_label: __param_target
   - source_labels: [__param_target]
     target_label: instance
   - target_label: __address__
     replacement: prometheus-blackbox-exporter:9115 # The blackbox exporter.

Generiramo Tajni, z uporabo naslednjega ukaza.

PROMETHEUS_ADD_CONFIG=$(cat prometheus-additional.yaml | base64)
cat << EOF | kubectl --namespace=monitoring apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: additional-scrape-configs
type: Opaque
data:
  prometheus-additional.yaml: $PROMETHEUS_ADD_CONFIG
EOF

Navodimo additional-scrape-configs za Prometheus Operator, z uporabo additionalScrapeConfigs.

kubectl --namespace=monitoring edit prometheuses k8s
...
spec:
  additionalScrapeConfigs:
    key: prometheus-additional.yaml
    name: additional-scrape-configs

Vstopimo v spletni vmesnik Prometheus, preverimo metrike in cilje.

kubectl --namespace=monitoring port-forward svc/prometheus-k8s 9090:9090

Vidimo metrične podatke in cilje Blackbox.

Dodajanje pravil za obvestila (alert)

Za prejemanje obvestil od Blackbox izvoznika dodamo pravila v Prometheus Operator.

kubectl --namespace=monitoring edit prometheusrules prometheus-k8s-rules
...
  - name: blackbox-exporter
    rules:
    - alert: ProbeFailed
      expr: probe_success == 0
      for: 5m
      labels:
        severity: error
      annotations:
        summary: "Probe failed (instance {{ $labels.instance }})"
        description: "Probe failedn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: SlowProbe
      expr: avg_over_time(probe_duration_seconds[1m]) > 1
      for: 5m
      labels:
        severity: warning
      annotations:
        summary: "Slow probe (instance {{ $labels.instance }})"
        description: "Blackbox probe took more than 1s to completen  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: HttpStatusCode
      expr: probe_http_status_code = 400
      for: 5m
      labels:
        severity: error
      annotations:
        summary: "HTTP Status Code (instance {{ $labels.instance }})"
        description: "HTTP status code is not 200-399n  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: SslCertificateWillExpireSoon
      expr: probe_ssl_earliest_cert_expiry - time() < 86400 * 30
      for: 5m
      labels:
        severity: warning
      annotations:
        summary: "SSL certificate will expire soon (instance {{ $labels.instance }})"
        description: "SSL certificate expires in 30 daysn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: SslCertificateHasExpired
      expr: probe_ssl_earliest_cert_expiry - time()  1
      for: 5m
      labels:
        severity: warning
      annotations:
        summary: "HTTP slow requests (instance {{ $labels.instance }})"
        description: "HTTP request took more than 1sn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: SlowPing
      expr: avg_over_time(probe_icmp_duration_seconds[1m]) > 1
      for: 5m
      labels:
        severity: warning
      annotations:
        summary: "Slow ping (instance {{ $labels.instance }})"
        description: "Blackbox ping took more than 1sn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"

V veb-interfeyse Prometheus pereydite v razdel Status => Rules i naydite pravila opovescheniy dlya blackbox-exporter.

Nastroyka uvidomleniy ob istechenii sroka deystviya SSL-certifikatov Kubernetes API Server

Davajte nastroyim monitoring istecheniya sroka deystviya SSL-certifikatov Kubernetes API Server. On budet otpravlyat uvidomleniya odin raz v nedelyu.

Dobavlyaem modul' Blackbox eksportera dlya Kubernetes API Server Authentication.

kubectl --namespace=monitoring edit configmap prometheus-blackbox-exporter
...
      kube-api:
        http:
          method: GET
          no_follow_redirects: false
          preferred_ip_protocol: ip4
          tls_config:
            insecure_skip_verify: false
            ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
          bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
          valid_http_versions:
          - HTTP/1.1
          - HTTP/2
          valid_status_codes: []
        prober: http
        timeout: 5s

Dobavlyaem scrape-konfiguratsiyu Prometheus

- job_name: 'kube-api-blackbox'
  metrics_path: /probe
  params:
    module: [kube-api]
  static_configs:
   - targets:
      - https://kubernetes.default.svc/api
  relabel_configs:
   - source_labels: [__address__]
     target_label: __param_target
   - source_labels: [__param_target]
     target_label: instance
   - target_label: __address__
     replacement: prometheus-blackbox-exporter:9115 # The blackbox exporter.

Uporabljamo Prometheus Secret

PROMETHEUS_ADD_CONFIG=$(cat prometheus-additional.yaml | base64)
cat << EOF | kubectl --namespace=monitoring apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: additional-scrape-configs
type: Opaque
data:
  prometheus-additional.yaml: $PROMETHEUS_ADD_CONFIG
EOF

Dodajamo pravila opozarjanja

kubectl --namespace=monitoring edit prometheusrules prometheus-k8s-rules
...
  - name: k8s-api-server-cert-expiry
    rules:
    - alert: K8sAPIServerSSLCertExpiringAfterThreeMonths
      expr: probe_ssl_earliest_cert_expiry{job="kube-api-blackbox"} - time() < 86400 * 90 
      for: 1w
      labels:
        severity: warning
      annotations:
        summary: "SSL certifikat Kubernetes API strežnika se bo iztekel čez tri mesece (instance {{ $labels.instance }})"
        description: "SSL certifikat Kubernetes API strežnika se izteče v 90 dneh
  VALUE = {{ $value }}
  LABELS: {{ $labels }}"