🥇Prometheus: Monitorovanie HTTP prostredníctvom exportéra Blackbox

Ahojte všetci. V máji štartuje OTUS workshop o monitorovaní a protokolovaní, infraštruktúru aj aplikácie využívajúce Zabbix, Prometheus, Grafana a ELK. V tejto súvislosti už tradične zdieľame užitočný materiál na túto tému.

Blackbox exportér for Prometheus umožňuje implementovať monitorovanie externých služieb cez HTTP, HTTPS, DNS, TCP, ICMP. V tomto článku vám ukážem, ako nastaviť monitorovanie HTTP/HTTPS pomocou exportéra Blackbox. Exportér Blackbox spustíme v Kubernetes.

okolia

Budeme potrebovať nasledovné:

Kubernetes
Operátor Prometheus

Konfigurácia čiernej skrinky exportéra

Konfigurácia Blackbox cez ConfigMap pre nastavenia http modul na monitorovanie webových služieb.

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 používa sa na kontrolu, či webová služba vracia stavový kód HTTP 2xx. Konfigurácia exportéra blackboxu je podrobnejšie popísaná v dokumentáciu.

Nasadenie exportéra blackboxu do klastra Kubernetes

Popíšte Deployment и Service na nasadenie v 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 exporter je možné nasadiť pomocou nasledujúceho príkazu. Menný priestor monitoring odkazuje na prevádzkovateľa Prometheus.

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

Uistite sa, že všetky služby bežia pomocou nasledujúceho príkazu:

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

Kontrola blackboxu

K webovému rozhraniu exportéra Blackbox môžete pristupovať pomocou port-forward:

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

Pripojte sa k webovému rozhraniu exportéra Blackbox cez webový prehliadač na adrese localhost: 9115.

Ak pôjdete na adresu http://localhost:9115/probe?module=http_2xx&target=https://www.google.com, uvidíte výsledok kontroly zadanej adresy URL (https://www.google.com).

Metrická hodnota probe_success rovná 1 znamená úspešnú kontrolu. Hodnota 0 označuje chybu.

Nastavenie programu Prometheus

Po nasadení exportéra BlackBox nakonfigurujeme 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.

Vytvárame Secretpomocou nasledujúceho príkazu.

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

Naznačujeme additional-scrape-configs pre operátora Prometheus additionalScrapeConfigs.

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

Prejdeme do webového rozhrania Prometheus a skontrolujeme metriky a ciele.

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

Vidíme metriky a ciele Blackboxu.

Pridanie pravidiel pre upozornenia (upozornenie)

Ak chcete dostávať upozornenia od exportéra Blackbox, pridáme pravidlá do operátora Prometheus.

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 <= 199 OR 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()  <= 0
      for: 5m
      labels:
        severity: error
      annotations:
        summary: "SSL certificate has expired (instance {{ $labels.instance }})"
        description: "SSL certificate has expired alreadyn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"
    - alert: HttpSlowRequests
      expr: avg_over_time(probe_http_duration_seconds[1m]) > 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 }}"

Vo webovom rozhraní Prometheus prejdite na Stav => Pravidlá a nájdite pravidlá upozornenia pre blackbox-exporter.

Konfigurácia upozornení na vypršanie platnosti certifikátu SSL servera Kubernetes API

Poďme nakonfigurovať sledovanie platnosti certifikátu SSL servera Kubernetes API. Bude posielať upozornenia raz týždenne.

Pridanie modulu exportéra Blackbox pre autentifikáciu servera Kubernetes API.

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

Pridáva sa konfigurácia zoškrabovania 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.

Pomocou 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

Pridávanie pravidiel varovania

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: "Kubernetes API Server SSL certificate will expire after three months (instance {{ $labels.instance }})"
        description: "Kubernetes API Server SSL certificate expires in 90 daysn  VALUE = {{ $value }}n  LABELS: {{ $labels }}"

Užitočné odkazy

Monitorovanie a prihlasovanie v Dockeri

Zdroj: hab.com