Questo argomento descrive come configurare le metriche definite dall'utente per la scalabilità automatica orizzontale dei pod (HPA) in Google Distributed Cloud.
Esegui il deployment di Prometheus e dell'adattatore per le metriche
In questa sezione eseguirai il deployment di Prometheus per eseguire lo scraping delle metriche definite dall'utente e dell'adattatore prometheus per evadere l'API Kubernetes Custom Metrics con Prometheus come backend.
Salva i seguenti manifest in un file denominato custom-metrics-adapter.yaml.
Contenuti del file manifest per Prometheus e Metrics Adapter
# Copyright 2018 Google Inc
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
apiVersion: v1
kind: ServiceAccount
metadata:
name: stackdriver-prometheus
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: stackdriver-prometheus
namespace: kube-system
rules:
- apiGroups:
- ""
resources:
- nodes
- services
- endpoints
- pods
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: stackdriver-prometheus
namespace: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: stackdriver-prometheus
subjects:
- kind: ServiceAccount
name: stackdriver-prometheus
namespace: kube-system
---
apiVersion: v1
kind: Service
metadata:
name: stackdriver-prometheus-app
namespace: kube-system
labels:
app: stackdriver-prometheus-app
spec:
clusterIP: "None"
ports:
- name: http
port: 9090
protocol: TCP
targetPort: 9090
sessionAffinity: ClientIP
selector:
app: stackdriver-prometheus-app
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: stackdriver-prometheus-app
namespace: kube-system
labels:
app: stackdriver-prometheus-app
spec:
replicas: 1
selector:
matchLabels:
app: stackdriver-prometheus-app
template:
metadata:
labels:
app: stackdriver-prometheus-app
spec:
serviceAccount: stackdriver-prometheus
containers:
- name: prometheus-server
image: prom/prometheus:v2.45.0
args:
- "--config.file=/etc/prometheus/config/prometheus.yaml"
- "--storage.tsdb.path=/data"
- "--storage.tsdb.retention.time=2h"
ports:
- name: prometheus
containerPort: 9090
readinessProbe:
httpGet:
path: /-/ready
port: 9090
periodSeconds: 5
timeoutSeconds: 3
# Allow up to 10m on startup for data recovery
failureThreshold: 120
livenessProbe:
httpGet:
path: /-/healthy
port: 9090
periodSeconds: 5
timeoutSeconds: 3
failureThreshold: 6
resources:
requests:
cpu: 250m
memory: 500Mi
volumeMounts:
- name: config-volume
mountPath: /etc/prometheus/config
- name: stackdriver-prometheus-app-data
mountPath: /data
volumes:
- name: config-volume
configMap:
name: stackdriver-prometheus-app
- name: stackdriver-prometheus-app-data
emptyDir: {}
terminationGracePeriodSeconds: 300
nodeSelector:
kubernetes.io/os: linux
---
apiVersion: v1
data:
prometheus.yaml: |
global:
scrape_interval: 1m
rule_files:
- /etc/config/rules.yaml
- /etc/config/alerts.yaml
scrape_configs:
- job_name: prometheus-io-endpoints
kubernetes_sd_configs:
- role: endpoints
relabel_configs:
- action: keep
regex: true
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_scrape
- action: replace
regex: (.+)
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_path
target_label: __metrics_path__
- action: replace
regex: (https?)
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_scheme
target_label: __scheme__
- action: replace
regex: ([^:]+)(?::\d+)?;(\d+)
replacement: $1:$2
source_labels:
- __address__
- __meta_kubernetes_service_annotation_prometheus_io_port
target_label: __address__
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- action: keep
regex: (.+)
source_labels:
- __meta_kubernetes_endpoint_port_name
- job_name: prometheus-io-services
kubernetes_sd_configs:
- role: service
metrics_path: /probe
params:
module:
- http_2xx
relabel_configs:
- action: replace
source_labels:
- __address__
target_label: __param_target
- action: replace
replacement: blackbox
target_label: __address__
- action: keep
regex: true
source_labels:
- __meta_kubernetes_service_annotation_prometheus_io_probe
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
- job_name: prometheus-io-pods
kubernetes_sd_configs:
- role: pod
relabel_configs:
- action: keep
regex: true
source_labels:
- __meta_kubernetes_pod_annotation_prometheus_io_scrape
- action: replace
regex: (.+)
source_labels:
- __meta_kubernetes_pod_annotation_prometheus_io_path
target_label: __metrics_path__
- action: replace
regex: ([^:]+)(?::\d+)?;(\d+)
replacement: $1:$2
source_labels:
- __address__
- __meta_kubernetes_pod_annotation_prometheus_io_port
target_label: __address__
- action: replace
source_labels:
- __meta_kubernetes_namespace
target_label: namespace
- action: replace
source_labels:
- __meta_kubernetes_pod_name
target_label: pod
kind: ConfigMap
metadata:
name: stackdriver-prometheus-app
namespace: kube-system
---
# The main section of custom metrics adapter.
kind: ServiceAccount
apiVersion: v1
metadata:
name: custom-metrics-apiserver
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: custom-metrics:system:auth-delegator
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:auth-delegator
subjects:
- kind: ServiceAccount
name: custom-metrics-apiserver
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: custom-metrics-server-resources
rules:
- apiGroups:
- custom.metrics.k8s.io
resources: ["*"]
verbs: ["*"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: custom-metrics-resource-reader
rules:
- apiGroups:
- ""
resources:
- nodes
- namespaces
- pods
- services
verbs:
- get
- watch
- list
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: custom-metrics-resource-reader
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: custom-metrics-resource-reader
subjects:
- kind: ServiceAccount
name: custom-metrics-apiserver
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: custom-metrics-auth-reader
namespace: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: extension-apiserver-authentication-reader
subjects:
- kind: ServiceAccount
name: custom-metrics-apiserver
namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
name: adapter-config
namespace: kube-system
data:
config.yaml: |
rules:
default: false
# fliter all metrics
- seriesQuery: '{pod=~".+"}'
seriesFilters: []
resources:
# resource name is mapped as it is. ex. namespace -> namespace
template: <<.Resource>>
name:
matches: ^(.*)$
as: ""
# Aggregate metric on resource level
metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>}) by (<<.GroupBy>>)
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: custom-metrics-apiserver
name: custom-metrics-apiserver
namespace: kube-system
spec:
replicas: 1
selector:
matchLabels:
app: custom-metrics-apiserver
template:
metadata:
labels:
app: custom-metrics-apiserver
name: custom-metrics-apiserver
spec:
serviceAccountName: custom-metrics-apiserver
containers:
- name: custom-metrics-apiserver
resources:
requests:
cpu: 15m
memory: 20Mi
limits:
cpu: 100m
memory: 150Mi
image: registry.k8s.io/prometheus-adapter/prometheus-adapter:v0.11.0
args:
- /adapter
- --cert-dir=/var/run/serving-cert
- --secure-port=6443
- --prometheus-url=http://stackdriver-prometheus-app.kube-system.svc:9090/
- --metrics-relist-interval=1m
- --config=/etc/adapter/config.yaml
ports:
- containerPort: 6443
volumeMounts:
- name: serving-cert
mountPath: /var/run/serving-cert
- mountPath: /etc/adapter/
name: config
readOnly: true
nodeSelector:
kubernetes.io/os: linux
volumes:
- name: serving-cert
emptyDir:
medium: Memory
- name: config
configMap:
name: adapter-config
---
apiVersion: v1
kind: Service
metadata:
name: custom-metrics-apiserver
namespace: kube-system
spec:
ports:
- port: 443
targetPort: 6443
selector:
app: custom-metrics-apiserver
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
name: v1beta1.custom.metrics.k8s.io
spec:
service:
name: custom-metrics-apiserver
namespace: kube-system
group: custom.metrics.k8s.io
version: v1beta1
insecureSkipTLSVerify: true
groupPriorityMinimum: 100
versionPriority: 100
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
name: v1beta2.custom.metrics.k8s.io
spec:
service:
name: custom-metrics-apiserver
namespace: kube-system
group: custom.metrics.k8s.io
version: v1beta2
insecureSkipTLSVerify: true
groupPriorityMinimum: 100
versionPriority: 100
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: hpa-controller-custom-metrics
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: custom-metrics-server-resources
subjects:
- kind: ServiceAccount
name: horizontal-pod-autoscaler
namespace: kube-system
Crea il deployment e il servizio:
kubectl --kubeconfig USER_CLUSTER_KUBECONFIG apply -f custom-metrics-adapter.yaml
Il passaggio successivo consiste nell'aggiungere annotazioni all'applicazione utente per la raccolta delle metriche.
Annota un'applicazione utente per la raccolta di metriche
Per annotare un'applicazione utente da estrarre e i log inviati a Cloud Monitoring, devi aggiungere il valore annotations corrispondente ai metadati del servizio, del pod e degli endpoint.
metadata:
name: "example-monitoring"
namespace: "default"
annotations:
prometheus.io/scrape: "true"
prometheus.io/path: "" - Overriding metrics path (default "/metrics")
Deployment di un'applicazione utente di esempio
In questa sezione eseguirai il deployment di un'applicazione di esempio con log e metriche compatibili con Prometheus.
Salva i seguenti manifest del servizio e del deployment in un file denominato
my-app.yaml. Nota che il servizio ha l'annotazioneprometheus.io/scrape: "true":kind: Service apiVersion: v1 metadata: name: "example-monitoring" namespace: "default" annotations: prometheus.io/scrape: "true" spec: selector: app: "example-monitoring" ports: - name: http port: 9090 --- apiVersion: apps/v1 kind: Deployment metadata: name: "example-monitoring" namespace: "default" labels: app: "example-monitoring" spec: replicas: 1 selector: matchLabels: app: "example-monitoring" template: metadata: labels: app: "example-monitoring" spec: containers: - image: gcr.io/google-samples/prometheus-dummy-exporter:v0.2.0 name: prometheus-example-exporter command: - ./prometheus-dummy-exporter args: - --metric-name=example_monitoring_up - --metric-value=1 - --port=9090 resources: requests: cpu: 100mCrea il deployment e il servizio:
kubectl --kubeconfig USER_CLUSTER_KUBECONFIG apply -f my-app.yaml
Utilizzare le metriche personalizzate in HPA
Esegui il deployment dell'oggetto HPA per utilizzare la metrica esposta nel passaggio precedente. Per informazioni più specifiche sui diversi tipi di metriche personalizzate, consulta Scalabilità automatica su più metriche e metriche personalizzate.
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: example-monitoring-hpa
namespace: default
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: example-monitoring
minReplicas: 1
maxReplicas: 5
metrics:
- type: Pods
pods:
metric:
name: example_monitoring_up
target:
type: AverageValue
averageValue: 20
La metrica del tipo di pod ha un selettore di metriche predefinito per le etichette dei pod di destinazione, ovvero come funziona kube-controller-manager. In questo esempio, esegui una query sulla metrica example_monitoring_up con un selettore {matchLabels: {app: example-monitoring}} in quanto disponibili nei pod di destinazione. Qualsiasi altro selettore specificato viene aggiunto all'elenco. Per evitare il selettore predefinito, puoi rimuovere eventuali etichette sul pod di destinazione o utilizzare la metrica Tipo di oggetto.
Verificare che le metriche dell'applicazione definite dall'utente vengano utilizzate da HPA
Verifica che le metriche dell'applicazione definite dall'utente siano utilizzate da HPA:
kubectl --kubeconfig=USER_CLUSTER_KUBECONFIG describe hpa example-monitoring-hpa
L'output sarà simile al seguente:
Name: example-monitoring-hpa Namespace: default Labels:Annotations: autoscaling.alpha.kubernetes.io/conditions: [{"type":"AbleToScale","status":"True","lastTransitionTime":"2023-08-23T22:07:24Z","reason":"ReadyForNewScale","message":"recommended size... autoscaling.alpha.kubernetes.io/current-metrics: [{"type":"Pods","pods":{"metricName":"example_monitoring_up","currentAverageValue":"1"}}] autoscaling.alpha.kubernetes.io/metrics: [{"type":"Pods","pods":{"metricName":"example_monitoring_up","targetAverageValue":"20"}}] CreationTimestamp: Wed, 23 Aug 2023 22:07:09 +0000 Reference: Deployment/example-monitoring Min replicas: 1 Max replicas: 5 Deployment pods: 1 current / 1 desired
Costi
L'utilizzo di metriche personalizzate per HPA non comporta addebiti aggiuntivi di Cloud Monitoring. I pod per l'abilitazione di metriche personalizzate consumano CPU e memoria aggiuntive in base alla quantità di metriche utilizzate.