1. 什么是 helm?

kubernetes的包管理器

  • 定义/安装/升级 kubernetes应用程序(helm chart)
  • 容易创建/发布/分享

2. 使用Helm

2.1 安装

  • from the homebrew

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    brew install helm

  • for apt

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    curl https://baltocdn.com/helm/signing.asc | sudo apt-key add -
    sudo apt-get install apt-transport-https --yes
    echo "deb https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
    sudo apt-get update
    sudo apt-get install helm

2.2 使用

  • 添加本地本地仓库

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    helm repo add bitnami https://charts.bitnami.com/bitnami

  • 查看仓库中的chart

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    helm search repo bitnami

  • 查看chart信息

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    helm show chart bitnami/mysql
    helm show readme bitnami/mysql
    helm show all bitnami/mysql

  • 安装一个chart

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    helm repo update              # Make sure we get the latest list of charts
    helm install bitnami/mysql --generate-name

  • 列表已安装的chart

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    helm list

  • 查看已安装chart状态

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    helm status mysql-1612624192

  • 删除chart

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    helm uninstall mysql-1612624192

2.3 结合Terraform使用

helm provider仅有一个resource: helm_release, 可以实现如下的效果:

  • 安装chart

  • 安装本地chart

  • 安装仓库
    helm provider使用前需要配置kubernetes权限, 这个配置和kubenetes provider的配置类似, 例如:

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    # 使用kubeconfig文件
    provider "helm" {
    kubernetes {
      config_path = "~/.kube/config"
    }
    }

    # 使用可执行插件

    data "aws_eks_cluster" "main" {
      name = "test-eks-cluster"
    }
    provider "helm" {
      kubernetes {
        host                   = data.aws_eks_cluster.main.endpoint
        cluster_ca_certificate = base64decode(data.aws_eks_cluster.main.certificate_authority[0].data)
        exec {
          api_version = "client.authentication.k8s.io/v1alpha1"
          args        = ["eks", "get-token", "--cluster-name", data.aws_eks_cluster.main.name]
          command     = "aws"
        }
      }
    }

    # 使用临时token
    data "aws_eks_cluster_auth" "main" {
      name = "test-eks-cluster"
    }
    provider "helm" {
      host                   = data.aws_eks_cluster.main.endpoint
      token                  = data.aws_eks_cluster_auth.main.token
      cluster_ca_certificate = base64decode(data.aws_eks_cluster.main.certificate_authority[0].data)
    }

2.4 使用案例

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# 使用chart url
resource "helm_release" "example1" {
  name  = "redis"
  chart = "https://charts.bitnami.com/bitnami/redis-10.7.16.tgz"
}
# 使用本地地址
resource "helm_release" "example2" {
  name       = "my-local-chart"
  chart      = "./charts/example"
}
# 使用chart仓库
resource "helm_release" "example" {
  name       = "my-redis-release"
  repository = "https://charts.bitnami.com/bitnami"
  chart      = "redis"
  version    = "6.0.1"

  values = [
    "${file("values.yaml")}"
  ]
  set {
    name  = "cluster.enabled"
    value = "true"
  }
}

3. 总结

helm本质上解决了重复代码的问题, 将 mysql/minio/cert manage/dashboard 等诸多常用的kubernetes应用和配置当成包一样的进行管理, 避免了我们去查资料, 拷贝yaml, 修改yaml最后应用yaml的诸多麻烦, 而云厂商例如aws也有自己的chart仓库, 实践中能增加效率, 让开发者主要聚焦到自有应用程序的发布, 而不是疲惫与基础kubernetes环境的搭建.