在这个例子中，我们将在Kubernetes集群中用Prometheus收集Golang应用程序的指标。然后我们将检查Prometheus的情况。
在这个例子中，有两个重要的点。首先是，Prometheus会自动发现任何暴露了/metrics 端点的新应用。你不需要改变Prometheus的配置。第二个还没有实现，所以你需要添加它。指标目前是不持久的。如果你重新启动你的pods，你会失去它们，这不是一个理想的情况。这是一个 "必须具备 "的功能，而不是一个 "不错的功能"。
结构
├── Makefile
├── deploy
│ └── k8s
│ ├── deployment.yaml
│ └── service.yaml
├── docker
│ └── Dockerfile
└── main.go
文件
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: football-deployment
namespace: default
labels:
app: football
spec:
replicas: 1
selector:
matchLabels:
app: football
template:
metadata:
labels:
app: football
spec:
containers:
- name: golang
image: you/football:latest
ports:
- containerPort: 3000
service.yaml
apiVersion: v1
kind: Service
metadata:
name: football-service
namespace: default
spec:
type: NodePort
selector:
app: football
ports:
- protocol: TCP
port: 80
targetPort: 3000
Docker文件
FROM golang:1.15-alpine3.12 as build
WORKDIR /source
COPY . .
RUN CGO_ENABLED=0 go build -ldflags "-s -w" -o bin/main main.go
FROM alpine:3.12
COPY --from=build /source/bin/main /main
ENTRYPOINT ["/main"]
main.go
package main
import (
"log"
"net/http"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
func main() {
rtr := http.NewServeMux()
rtr.HandleFunc("/metrics", promhttp.Handler().ServeHTTP)
rtr.HandleFunc("/api/v1/leagues", league)
if err := http.ListenAndServe(":3000", rtr); err != nil && err != http.ErrServerClosed {
log.Fatalln(err)
}
}
func league(w http.ResponseWriter, _ *http.Request) {
counter.Inc()
_, _ = w.Write([]byte("FIFA"))
}
// Auto register counter metrics.
var counter = promauto.NewCounter(prometheus.CounterOpts{
Namespace: "football",
Name: "leagues_request_counter",
Help: "Number of requests",
})
制作文件
## LOCAL -----------------------------------------------------------------------
.PHONY: run
run:
go build -race -ldflags "-s -w" -o bin/main main.go
bin/main
.PHONY: test
test:
curl --request GET http://localhost:3000/api/v1/leagues
## DOCKER ----------------------------------------------------------------------
.PHONY: docker-push
docker-push:
docker build -t you/football:latest -f ./docker/Dockerfile .
docker push you/football:latest
docker rmi you/football:latest
docker system prune --volumes --force
## KUBE ------------------------------------------------------------------------
.PHONY: kube-deploy
kube-deploy:
kubectl apply -f deploy/k8s/deployment.yaml
kubectl apply -f deploy/k8s/service.yaml
.PHONY: kube-test
kube-test:
curl --request GET $(shell minikube service football-service --url)/api/v1/leagues
监控
结构
├── Makefile
└── deploy
└── k8s
├── monitor
│ ├── cluster-role-binding.yaml
│ ├── cluster-role.yaml
│ └── service-account.yaml
└── prometheus
├── config-map.yaml
├── deployment.yaml
└── service.yaml
文件
cluster-role-binding.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: monitor-cluster-role-binding
roleRef:
kind: ClusterRole
name: monitor-cluster-role
apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
name: monitor-service-account
namespace: default
# Grant permissions defined in a cluster role to user(s) in the whole cluster.
cluster-role.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: monitor-cluster-role
rules:
- apiGroups: [""]
resources: ["services", "pods", "endpoints"]
verbs: ["get", "watch", "list"]
- nonResourceURLs: ["/metrics"]
verbs: ["get"]
# Grant read access to all services, pods, endpoints and /metrics URLs in the
# whole cluster. Run commands below to confirm role permissions. You sould get
# "yes".
# kubectl auth can-i get services --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i list services --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i watch services --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i get pods --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i list pods --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i watch pods --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i get endpoints --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i list endpoints --as=system:serviceaccount:default:monitor-service-account -n default
# kubectl auth can-i watch endpoints --as=system:serviceaccount:default:monitor-service-account -n default
service-account.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: monitor-service-account
namespace: default
# Help Prometheus represent its identity in the cluster.
config-map.yaml
查看这个例子以了解更详细的配置选项。
apiVersion: v1
kind: ConfigMap
metadata:
name: prometheus-config-map
namespace: default
data:
prometheus.yml: |
global:
scrape_interval: 15s
scrape_timeout: 15s
scrape_configs:
- job_name: application-metrics
metrics_path: /metrics
kubernetes_sd_configs:
- role: endpoints
relabel_configs:
- action: labelmap
regex: __meta_kubernetes_service_label_(.+)
- source_labels: [__meta_kubernetes_namespace]
action: replace
target_label: namespace
- source_labels: [__meta_kubernetes_service_name]
action: replace
target_label: service
# Given that we exposed our applications as services, watch for any service
# endpoints shipping Prometheus-format metrics with Kubernetes auto-discover
# plugin kubernetes_sd_configs. If you want to ignore other services that expose
# metrics via /metrics endpoint, a workaround is to change your application
# metrics path to something else. e.g. /app/metrics
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: prometheus-deployment
namespace: default
labels:
app: prometheus
spec:
replicas: 1
selector:
matchLabels:
app: prometheus
template:
metadata:
labels:
app: prometheus
spec:
serviceAccountName: monitor-service-account
containers:
- name: prometheus
image: prom/prometheus:latest
resources:
limits:
cpu: "1000m" # 1 core
memory: "1024Mi" # 1 GB
requests:
cpu: "500m" # 0.5 core
memory: "512Mi" # 0.5 GB
ports:
- name: http
protocol: TCP
containerPort: 9090
volumeMounts:
- name: config
mountPath: /etc/prometheus/
- name: storage
mountPath: /prometheus/
volumes:
- name: config
configMap:
name: prometheus-config-map
- name: storage
emptyDir: {}
service.yaml
apiVersion: v1
kind: Service
metadata:
name: prometheus-service
namespace: default
spec:
type: NodePort
selector:
app: prometheus
ports:
- name: http
protocol: TCP
port: 80
targetPort: 9090
制作文件
.PHONY: deploy-roles
deploy-roles:
kubectl apply -f deploy/k8s/monitor/cluster-role.yaml
kubectl apply -f deploy/k8s/monitor/service-account.yaml
kubectl apply -f deploy/k8s/monitor/cluster-role-binding.yaml
.PHONY: deploy-prometheus
deploy-prometheus:
kubectl apply -f deploy/k8s/prometheus/config-map.yaml
kubectl apply -f deploy/k8s/prometheus/deployment.yaml
kubectl apply -f deploy/k8s/prometheus/service.yaml
测试
我正在使用Minikube，所以我必须在启用RBAC的情况下启动它。
$ minikube start --vm-driver=virtualbox --extra-config=apiserver.Authorization.Mode=RBAC
apiserver.Authorization.Mode=RBAC
部署Golang
我假设你已经用football$ make docker-push 命令将应用程序推送到DockerHub。运行下面的命令来部署它。
football$ make kube-deploy
kubectl apply -f deploy/k8s/deployment.yaml
deployment.apps/football-deployment created
kubectl apply -f deploy/k8s/service.yaml
service/football-service created
部署监控
monitoring$ make deploy-roles
kubectl apply -f deploy/k8s/monitor/cluster-role.yaml
clusterrole.rbac.authorization.k8s.io/monitor-cluster-role created
kubectl apply -f deploy/k8s/monitor/service-account.yaml
serviceaccount/monitor-service-account created
kubectl apply -f deploy/k8s/monitor/cluster-role-binding.yaml
clusterrolebinding.rbac.authorization.k8s.io/monitor-cluster-role-binding created
monitoring$ make deploy-prometheus
kubectl apply -f deploy/k8s/prometheus/config-map.yaml
configmap/prometheus-config-map created
kubectl apply -f deploy/k8s/prometheus/deployment.yaml
deployment.apps/prometheus-deployment created
kubectl apply -f deploy/k8s/prometheus/service.yaml
service/prometheus-service created
获得用户界面的Prometheus IP地址：
$ minikube service prometheus-service --url --namespace=default
http://192.168.99.101:30566
当你访问http://192.168.99.101:30566 ，你会看到许多指标，包括football_leagues_request_counter 。它看起来像下面：
football_leagues_request_counter{instance="172.17.0.5:3000",job="application-metrics",namespace="default",service="football-service"} 0
如果你运行football$ make kube-test 三次，你的指标会像下面这样变化：
football_leagues_request_counter{instance="172.17.0.5:3000",job="application-metrics",namespace="default",service="football-service"} 3
