開始使用 Helm 和 Helm Chart

ArtifactHub 為 Helm Chart 提供了公共和私有資源庫。我們將使用這些 Helm Chart 來設置 Kubernetes 集群中的 pod 和服務。

Helm 社區為各種 Kubernetes 應用程序創建、管理和維護 Helm Chart，這些資源會時常更新。Helm Chart 可重復使用，安裝簡單。想要使用 Helm 在 Kubernetes 上集成 Prometheus ，讓我們從安裝 Helm 開始。

安裝 Helm

安裝 Helm 之前，必須使用以下命令啟動 Minikube Kubernetes：

minikube start --driver=docker

下圖顯示 Minikube 正在運行。Kubectl 工具現已配置為使用 Minikube。

接下來，使用以下命令（根據你使用的操作系統使用對應的命令）安裝 Helm：

在 Linux 上安裝 Helm

sudo apt-get install helm

在 Windows 上安裝 Helm

choco install Kubernetes-helm

在 macOS 系統上安裝 Helm

brew install helm

提示：如果遇到問題，可以查看 Helm 官方文檔指南 https://helm.sh/docs/intro/install/。

下圖顯示了 Helm 在 Windows 機器上的安裝情況：

Helm 命令

要獲取所有 Helm 命令，請運行此命令：

helm

命令輸出結果：

The Kubernetes package manager


Common actions for Helm:


- helm search:    search for charts
- helm pull:      download a chart to your local directory to view
- helm install:   upload the chart to Kubernetes
- helm list:      list releases of charts


Usage:
  helm [command]


Available Commands:
  completion  generate autocompletion scripts for the specified shell
  create      create a new chart with the given name
  dependency  manage a chart's dependencies
  env         helm client environment information
  get         download extended information of a named release
  help        Help about any command
  history     fetch release history
  install     install a chart
  lint        examine a chart for possible issues
  list        list releases
  package     package a chart directory into a chart archive
  plugin      install, list, or uninstall Helm plugins
  pull        download a chart from a repository and (optionally) unpack it in local directory
  push        push a chart to remote
  registry    login to or logout from a registry
  repo        add, list, remove, update, and index chart repositories
  rollback    roll back a release to a previous revision
  search      search for a keyword in charts
  show        show information of a chart
  status      display the status of the named release
  template    locally render templates
  test        run tests for a release
  uninstall   uninstall a release
  upgrade     upgrade a release
  verify      verify that a chart at the given path has been signed and is valid
  version     print the client version information


Use "helm [command] --help" for more information about a command.

最常用的 Helm 命令有

helm search：在 ArtifactHub 資源庫中搜索 Helm Chart。

helm pull：從 ArtifactHub 資源庫中提取并下載 Helm Chart。

helm install：上傳 Helm Chart 并將其部署到 Kubernetes 集群。

helm list：列出 Kubernetes 集群中部署的所有 Helm Chart。

Prometheus Helm Charts

首先，我們將搜索 Prometheus Helm Charts。要搜索 Prometheus Helm，請運行以下命令：

helm search hub prometheus

該命令列出以下 Prometheus Helm Chart：

URL                                                       CHART VERSION         APP VERSION                                           DESCRIPTION
https://artifacthub.io/packages/helm/prometheus...        25.1.0                v2.47.0                                               Prometheus is a monitoring system and time seri...
https://artifacthub.io/packages/helm/truecharts...        13.0.7                2.47.1                                                kube-prometheus-stack collects Kubernetes manif...
https://artifacthub.io/packages/helm/saurabh6-p...        0.2.0                 1.1                                                   This is a Helm Chart for Prometheus Setup.
https://artifacthub.io/packages/helm/prometheus...        13.0.0                2.22.1                                                Prometheus is a monitoring system and time seri...
https://artifacthub.io/packages/helm/wenerme/pr...        25.1.0                v2.47.0                                               Prometheus is a monitoring system and time seri...
https://artifacthub.io/packages/helm/wener/prom...        25.1.0                v2.47.0                                               Prometheus is a monitoring system and time seri...
https://artifacthub.io/packages/helm/romanow-he...        1.3.5                 2.40.0                                                Prometheus collects and stores its metrics as t...
https://artifacthub.io/packages/helm/mach1el-ch...        1.0.1                 v2.47.0                                               Prometheus Helm chart for Kubernetes
https://artifacthub.io/packages/helm/cloudposse...        0.2.1                                                                       Prometheus instance created by the CoreOS Prome...

您還可以前往 ArtifactHub 存儲庫（ https://artifacthub.io/）并搜索官方 Prometheus Helm Chart，如下圖所示：

列表中的第一個是官方的 Prometheus Helm Chart。要獲取此 Helm Chart，請運行以下命令：

helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo update

輸出結果：

"prometheus-community" has been added to your repositories
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "grafana" chart repository
...Successfully got an update from the "prometheus-community" chart repository
...Successfully got an update from the "bitnami" chart repository
Update Complete. ?Happy Helming!?

現在，我們已經下載好最新版本的 Prometheus 了。

在 K8s 集群上安裝 Prometheus Helm Chart

要在 K8s 集群上安裝 Prometheus Helm Chart，請運行以下helm install命令：

helm install prometheus prometheus-community/prometheus

輸出結果：

NAME: my-prometheus
LAST DEPLOYED: Thu Oct 12 20:06:57 2023
NAMESPACE: monitoring
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
The Prometheus server can be accessed via port 80 on the following DNS name from within your cluster:
my-prometheus-server.monitoring.svc.cluster.local




Get the Prometheus server URL by running these commands in the same shell:
  export POD_NAME=$(kubectl get pods --namespace monitoring -l "app.kubernetes.io/name=prometheus,app.kubernetes.io/instance=my-prometheus" -o jsonpath="{.items[0].metadata.name}")
  kubectl --namespace monitoring port-forward $POD_NAME 9090




The Prometheus alertmanager can be accessed via port 9093 on the following DNS name from within your cluster:
my-prometheus-alertmanager.monitoring.svc.cluster.local




Get the Alertmanager URL by running these commands in the same shell:
  export POD_NAME=$(kubectl get pods --namespace monitoring -l "app.kubernetes.io/name=alertmanager,app.kubernetes.io/instance=my-prometheus" -o jsonpath="{.items[0].metadata.name}")
  kubectl --namespace monitoring port-forward $POD_NAME 9093
#################################################################################
######   WARNING: Pod Security Policy has been disabled by default since    #####
######            it deprecated after k8s 1.25+. use                        #####
######            (index .Values "prometheus-node-exporter" "rbac"          #####
###### .          "pspEnabled") with (index .Values                         #####
######            "prometheus-node-exporter" "rbac" "pspAnnotations")       #####
######            in case you still need it.                                #####
#################################################################################




The Prometheus PushGateway can be accessed via port 9091 on the following DNS name from within your cluster:
my-prometheus-prometheus-pushgateway.monitoring.svc.cluster.local




Get the PushGateway URL by running these commands in the same shell:
  export POD_NAME=$(kubectl get pods --namespace monitoring -l "app=prometheus-pushgateway,component=pushgateway" -o jsonpath="{.items[0].metadata.name}")
  kubectl --namespace monitoring port-forward $POD_NAME 9091


For more information on running Prometheus, visit:
https://prometheus.io/

現在我們已經在 Kubernetes 集群上安裝了 Prometheus。我們可以通過80端口訪問 Prometheus 服務器。下一步是查看部署的 Kubernetes 資源，也就是 Helm Chart 在 Kubernetes 集群中創建的 Pod 和服務。

要查看已部署的 Kubernetes 資源，請運行以下kubectl命令：

kubectl get all

輸出結果：

NAME                                                        READY   STATUS    RESTARTS   AGE
pod/my-prometheus-prometheus-node-exporter-d5l8m            1/1     Running   0          27m
pod/my-prometheus-prometheus-node-exporter-kfbxb            1/1     Running   0          27m
pod/my-prometheus-prometheus-pushgateway-86d6f795cb-mlb7d   1/1     Running   0          27m
pod/my-prometheus-kube-state-metrics-6c4b65c7b9-wbh9r       1/1     Running   0          27m
pod/my-prometheus-prometheus-node-exporter-2z7rp            1/1     Running   0          27m
pod/my-prometheus-alertmanager-0                            1/1     Running   0          27m
pod/my-prometheus-server-795d8fc685-zcfct                   2/2     Running   0          27m


NAME                                             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
service/my-prometheus-alertmanager-headless      ClusterIP   None                    9093/TCP   27m
service/my-prometheus-server                     ClusterIP   10.43.186.10            80/TCP     27m
service/my-prometheus-prometheus-pushgateway     ClusterIP   10.43.154.83            9091/TCP   27m
service/my-prometheus-alertmanager               ClusterIP   10.43.217.41            9093/TCP   27m
service/my-prometheus-kube-state-metrics         ClusterIP   10.43.168.65            8080/TCP   27m
service/my-prometheus-prometheus-node-exporter   ClusterIP   10.43.195.241           9100/TCP   27m


NAME                                                    DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
daemonset.apps/my-prometheus-prometheus-node-exporter   3         3         3       3            3           kubernetes.io/os=linux   27m


NAME                                                   READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/my-prometheus-prometheus-pushgateway   1/1     1            1           27m
deployment.apps/my-prometheus-kube-state-metrics       1/1     1            1           27m
deployment.apps/my-prometheus-server                   1/1     1            1           27m


NAME                                                              DESIRED   CURRENT   READY   AGE
replicaset.apps/my-prometheus-prometheus-pushgateway-86d6f795cb   1         1         1       27m
replicaset.apps/my-prometheus-kube-state-metrics-6c4b65c7b9       1         1         1       27m
replicaset.apps/my-prometheus-server-795d8fc685                   1         1         1       27m


NAME                                          READY   AGE
statefulset.apps/my-prometheus-alertmanager   1/1     27m

安裝 Helm Chart 會創建以下 Kubernetes 資源：

Pod：托管集群內已部署的 Prometheus Kubernetes 應用程序。

Replica Sets：Kubernetes 集群內同一應用程序實例的集合。它提高了應用程序的可靠性。

Deployments：這是創建應用程序 Pod 的藍圖。

Services：這是公開 Kubernetes 集群內運行的 Pod。我們用它來訪問已部署的 Kubernetes 應用程序。

下一步是訪問并啟動 Prometheus Kubernetes 應用程序。這里將使用 Prometheus 的 Kubernetes 服務訪問該應用程序。要獲取 Prometheus 的所有 Kubernetes 服務，請運行以下命令：

kubectl get service

輸出結果：

NAME                                     TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
my-prometheus-alertmanager-headless      ClusterIP   None                    9093/TCP   28m
my-prometheus-server                     ClusterIP   10.43.186.10            80/TCP     28m
my-prometheus-prometheus-pushgateway     ClusterIP   10.43.154.83            9091/TCP   28m
my-prometheus-alertmanager               ClusterIP   10.43.217.41            9093/TCP   28m
my-prometheus-kube-state-metrics         ClusterIP   10.43.168.65            8080/TCP   28m
my-prometheus-prometheus-node-exporter   ClusterIP   10.43.195.241           9100/TCP   28m

輸出結果列出了 Prometheus 的下列 K8s service：

prometheus-alertmanager

prometheus-alertmanager-headless

prometheus-kube-state-metrics

prometheus-prometheus-node-exporter

prometheus-prometheus-pushgateway

prometheus-server

我們將使用prometheus-serverKubernetes service 來訪問 Prometheus 應用程序。prometheus-server是 ClusterIP 類型。您只能在 Kubernetes 集群內訪問它。因此我們需要公開這個 Kubernetes service，以便在 Kubernetes 集群外部訪問它。公開prometheus-serverKubernetes service 將生成一個 URL。我們可以在瀏覽器上加載 URL 并訪問正在運行的應用程序。

公開 prometheus-server Kubernetes service

要公開prometheus-serverKubernetes service，請運行以下命令：

kubectl expose service prometheus-server --type=NodePort --target-port=9090 --name=prometheus-server-ext

該命令會將ClusterIP類型轉換為NodePort類型。這樣，prometheus-server就能在 Kubernetes 集群之外通過 9090 端口訪問。

現在，我們公開了prometheus-serverKubernetes service。接下來使用以下命令訪問 Prometheus 應用程序：

minikube service prometheus-server-ext

該命令生成以下 URL：

URL 可能需要稍等一會兒才可用。您需要在瀏覽器上進行多次重試，直到使用此 URL 訪問 Prometheus Kubernetes 應用程序。您還需要保持終端打開并運行命令，以便繼續訪問服務。

到這里，我們已經成功使用 Helm 在 Kubernetes 上安裝了 Prometheus。Prometheus 已經在集群內部運行，我們可以使用瀏覽器或 URL 來進行訪問。

鏈接：https://blog.51cto.com/u_15682575/9174831

審核編輯：劉清