Terraform 部署容器服务Kubernetes集群及Wordpress应用

本文档介绍了如何通过 Terraform 在 VPC 环境下部署一个阿里云容器服务 Kubernetes 集群，并在该集群之上，部署一个 WordPress 样例应用。本文档提供一种构建阿里云基础设施的解决方案，让您通过代码来自动创建、编排和管理容器服务以及完成在容器集群上应用的自动化部署。

前提条件

• 需要开通阿里云容器服务，用户的账户需有 100 元余额并通过实名认证。
• 需要启用用户账号的 AccessKey，妥善保存和记录 AccessKey ID 和 AccessKey Secret。

步骤 1 安装 Terraform

详细信息参见 Terraform 部署容器服务Swarm集群及Wordpress应用

除了下载 Terraform 和阿里云的 Terraform Provider 之外，在运行 Wordpress 的模板之前，需要在 Kubernetes Terraform Provider 官方下载地址 下载对应版本和平台的 Provider。

步骤 2 下载容器服务 Kubernetes 的 Terraform 模板

您可以从 GitHub 上下载创建 Kubernetes 集群的 Terraform 模板（模板下载地址）。该模板文件定义了创建 Kubernetes 集群的相关资源，帮助您完成 Kubernetes 集群的快速创建和 Kube Config 的自动下载。

模板中包含以下文件。

main.tf

Terraform 主文件。定义了将要部署的资源。本模版加入了条件判断，可实现对已有网络资源的引用和多个 Kubernetes 集群的同时创建。

• 地域

定义了资源将要被创建在哪个地域里。

provider "alicloud" {
  access_key = "${var.alicloud_access_key}"
  secret_key = "${var.alicloud_secret_key}"
  region = "${var.region}"
}

• VPC

  指定 vpc_id 可使用已有 VPC。

  resource "alicloud_vpc" "vpc" {
    count = "${var.vpc_id == "" ? 1 : 0}"
    cidr_block = "${var.vpc_cidr}"
    name = "${var.vpc_name == "" ? var.example_name : var.vpc_name}"
  }

• VSwitch

  指定 vswitch_ids 可使用已有 VSwitch。

  resource "alicloud_vswitch" "vswitches" {
    count = "${length(var.vswitch_ids) > 0 ? 0 : length(var.vswitch_cidrs)}"
    vpc_id = "${var.vpc_id == "" ? join("", alicloud_vpc.vpc.*.id) : var.vpc_id}"
    cidr_block = "${element(var.vswitch_cidrs, count.index)}"
    availability_zone = "${lookup(data.alicloud_zones.default.zones[count.index%length(data.alicloud_zones.default.zones)], "id")}"
    name = "${var.vswitch_name_prefix == "" ? format("%s-%s", var.example_name, format(var.number_format, count.index+1)) : format("%s-%s", var.vswitch_name_prefix, format(var.number_format, count.index+1))}"
  }

• Nat Gateway

  指定 new_nat_gateway 来决定是否要为模板中定义的 VPC 自动创建 Nat Gateway，以保证 Kubernetes 集群成功创建。

  resource "alicloud_nat_gateway" "default" {
    count = "${var.new_nat_gateway == true ? 1 : 0}"
    vpc_id = "${var.vpc_id == "" ? join("", alicloud_vpc.vpc.*.id) : var.vpc_id}"
    name = "${var.example_name}"
  }

• EIP

  resource "alicloud_eip" "default" {
    count = "${var.new_nat_gateway == "true" ? 1 : 0}"
    bandwidth = 10
  }
  

• EIP Association

  resource "alicloud_eip_association" "default" {
    count = "${var.new_nat_gateway == "true" ? 1 : 0}"
    allocation_id = "${alicloud_eip.default.id}"
    instance_id = "${alicloud_nat_gateway.default.id}"
  }

• SNAT

  在模板中定义的 Nat Gateway 下自动添加 SNAT Entry 来保证 Kubernetes 集群成功创建。

  
  resource "alicloud_snat_entry" "default"{
    count = "${var.new_nat_gateway == "false" ? 0 : length(var.vswitch_ids) > 0 ? length(var.vswitch_ids) : length(var.vswitch_cidrs)}"
    snat_table_id = "${alicloud_nat_gateway.default.snat_table_ids}"
    source_vswitch_id = "${length(var.vswitch_ids) > 0 ? element(split(",", join(",", var.vswitch_ids)), count.index%length(split(",", join(",", var.vswitch_ids)))) : length(var.vswitch_cidrs) < 1 ? "" : element(split(",", join(",", alicloud_vswitch.vswitches.*.id)), count.index%length(split(",", join(",", alicloud_vswitch.vswitches.*.id))))}"
    snat_ip = "${alicloud_eip.default.ip_address}"
  }

• 容器服务 Kubernetes 集群

  改变 k8s_number 的值可同时创建多个 Kubernetes 集群。

  resource "alicloud_cs_kubernetes" "k8s" {
    count = "${var.k8s_number}"
    name = "${var.k8s_name_prefix == "" ? format("%s-%s", var.example_name, format(var.number_format, count.index+1)) : format("%s-%s", var.k8s_name_prefix, format(var.number_format, count.index+1))}"
    vswitch_id = "${length(var.vswitch_ids) > 0 ? element(split(",", join(",", var.vswitch_ids)), count.index%length(split(",", join(",", var.vswitch_ids)))) : length(var.vswitch_cidrs) < 1 ? "" : element(split(",", join(",", alicloud_vswitch.vswitches.*.id)), count.index%length(split(",", join(",", alicloud_vswitch.vswitches.*.id))))}"
    new_nat_gateway = false
    master_instance_type = "${var.master_instance_type == "" ? data.alicloud_instance_types.default.instance_types.0.id : var.master_instance_type}"
    worker_instance_type = "${var.worker_instance_type == "" ? data.alicloud_instance_types.default.instance_types.0.id : var.worker_instance_type}"
    worker_number = "${var.k8s_worker_number}"
    master_disk_category = "${var.master_disk_category}"
    worker_disk_category = "${var.worker_disk_category}"
    master_disk_size = "${var.master_disk_size}"
    worker_disk_size = "${var.master_disk_size}"
    password = "${var.ecs_password}"
    pod_cidr = "${var.k8s_pod_cidr}"
    service_cidr = "${var.k8s_service_cidr}"
    enable_ssh = true
    install_cloud_monitor = true
  
    depends_on = ["alicloud_snat_entry.default"]
  }
  
  ## 注意：指定 kube_config = "~/.kube/config" 可在 Kubernetes 集群创建完成后将 Kube Config 内容自动下载并存放在文件 `～/.kube/cofig` 中。

outputs.tf

该文件定义了输出参数。作为执行的一部分而创建的资源会生成这些输出参数。和 ROS 模板指定的输出参数类似。例如，该模板将部署一个 Kubernetes 集群。以下输出参数将提供集群 ID 和其他资源参数。

output "cluster_id" {
  value = "${alicloud_cs_swarm.cs_vpc.id}"
}

variables.tf

该文件包含可传递到 main.tf 的变量，可帮助您自定义环境。

variable "alicloud_access_key" {
  description = "The Alicloud Access Key ID to launch resources. Support to environment 'ALICLOUD_ACCESS_KEY'."
}

variable "alicloud_secret_key" {
  description = "The Alicloud Access Secret Key to launch resources.  Support to environment 'ALICLOUD_SECRET_KEY'."
}

variable "region" {
  description = "The region to launch resources."
  default = "cn-hongkong"
}

variable "vpc_cidr" {
  description = "The cidr block used to launch a new vpc."
  default = "172.16.0.0/12"
}

variable "vswitch_cidrs" {
  description = "List of cidr blocks used to create several new vswitches when 'vswitch_ids' is not specified."
  type = "list"
  default = ["10.1.2.0/24"]
}

variable "k8s_number" {
  description = "The number of kubernetes cluster."
  default = 1
}

variable "k8s_worker_number" {
  description = "The number of worker nodes in each kubernetes cluster."
  default = 3
}

步骤 3 执行 Kubernetes Terraform 脚本

首先，定位到您存放以上文件的目录，如 /root/terraform/kuberneters。然后，您可以利用以下 terraform 的相关命令，运行脚本，构建容器集群和部署应用。更多的命令用法和介绍，参见 [Terraform 部署容器服务Kubernetes集群及Wordpress应用]() 和 Terraform Commands (CLI)。

运行terraform apply 命令，开始创建 Kubernetes 集群。

$ terraform apply

data.alicloud_instance_types.default: Refreshing state...
data.alicloud_zones.default: Refreshing state...

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:
...

Plan: 7 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

alicloud_vpc.vpc: Creating...
...

Apply complete! Resources: 7 added, 0 changed, 0 destroyed.

Outputs:    ##注意

cluster_id = [
    c0f2e04c77e234******
]
......
vswitch_ids = [
    vsw-bp1c3hfcd6l80izqc3tbx
]

terraform apply 命令执行完毕后, 输出集群 ID 和其他参数。除此之外，将 Kubernetes 的 Kube Config 文件存放在了目录 ~/.kube 下。

您现在可以在容器服务控制台查看通过 terraform 创建的 Kubernetes 集群，查看集群信息、节点信息、日志信息和容器信息等信息。

步骤 4 下载 Wordpress 的 Terraform 模板

在创建好 Kubernetes 并完成了 Kube Config 的下载后，接下来就可以在 Kubernetes 上部署 Wordpress。 您可以从 GitHub 上下载创建 Wordpress 的 Terraform 模板（模板下载地址）。该模板文件是根据 Kubernetes Tutorials 编写的。模板中定义了创建 Wordpress 的相关资源和配置，帮助您完成在 Kubernetes 集群的快速搭建 Wordpress。

更多 Terraform Kubernetes 的操作可参考 Terraform 官网的 Kubernetes 文档介绍.

模板中包含以下文件。

localvolumes.tf

定义 Wordpress 和 Mysql 存储自己数据的 Persistent Volume。

• Persistent Volume

  
  resource "kubernetes_persistent_volume" "mysql" {
    metadata {
      name = "local-pv-mysql"
      labels {
        type = "local"
      }
    }
    spec {
      capacity {
        storage = "20Gi"
      }
      access_modes = ["ReadWriteOnce"]
      persistent_volume_source {
        host_path {
          path = "/tmp/data/pv-mysql"
        }
      }
    }
  }

mysql.tf

创建 MySQL 密码 Secret，并部署 MySQL。

• secret

  
  resource "kubernetes_secret" "mysql" {
    metadata {
      name = "mysql-pass"
    }
  
    data {
      password = "${var.mysql_password}"
    }
  }

• Deployment

  
  resource "kubernetes_service" "mysql" {
    metadata {
      name = "wordpress-mysql"
      labels {
        app = "wordpress"
      }
    }
    spec {
      port {
        port = 3306
      }
      selector {
        app = "wordpress"
        tier = "${kubernetes_replication_controller.mysql.spec.0.selector.tier}"
      }
      cluster_ip = "None"
    }
  }
  
  resource "kubernetes_replication_controller" "mysql" {
    metadata {
      name = "wordpress-mysql"
      labels {
        app = "wordpress"
      }
    }
    spec {
      selector {
        app = "wordpress"
        tier = "mysql"
      }
      template {
        container {
          image = "mysql:${var.mysql_version}"
          name  = "mysql"
  
          env {
            name = "MYSQL_ROOT_PASSWORD"
            value_from {
              secret_key_ref {
                name = "${kubernetes_secret.mysql.metadata.0.name}"
                key = "password"
              }
            }
          }
  
          port {
            container_port = 3306
            name = "mysql"
          }
  
          volume_mount {
            name = "mysql-persistent-storage"
            mount_path = "/var/lib/mysql"
          }
        }
  
        volume {
          name = "mysql-persistent-storage"
          persistent_volume_claim {
            claim_name = "${kubernetes_persistent_volume_claim.mysql.metadata.0.name}"
          }
        }
      }
    }
  }

wordpress.tf

接下来部署 Wordpress。

• Deployment

  
  resource "kubernetes_service" "wordpress" {
    metadata {
      name = "wordpress"
      labels {
        app = "wordpress"
      }
    }
    spec {
      port {
        port = 80
      }
      selector {
        app = "wordpress"
        tier = "${kubernetes_replication_controller.wordpress.spec.0.selector.tier}"
      }
      type = "LoadBalancer"
    }
  }
  
  
  resource "kubernetes_replication_controller" "wordpress" {
    metadata {
      name = "wordpress"
      labels {
        app = "wordpress"
      }
    }
    spec {
      selector {
        app = "wordpress"
        tier = "frontend"
      }
      template {
        container {
          image = "wordpress:${var.wordpress_version}-apache"
          name  = "wordpress"
  
          env {
            name = "WORDPRESS_DB_HOST"
            value = "wordpress-mysql"
          }
          env {
            name = "WORDPRESS_DB_PASSWORD"
            value_from {
              secret_key_ref {
                name = "${kubernetes_secret.mysql.metadata.0.name}"
                key = "password"
              }
            }
          }
  
          port {
            container_port = 80
            name = "wordpress"
          }
  
          volume_mount {
            name = "wordpress-persistent-storage"
            mount_path = "/var/www/html"
          }
        }
  
        volume {
          name = "wordpress-persistent-storage"
          persistent_volume_claim {
            claim_name = "${kubernetes_persistent_volume_claim.wordpress.metadata.0.name}"
          }
        }
      }
    }
  }

outputs.tf

该文件定义了输出参数。输出 Loadbalancer Public IP，借助该 IP 地址可直接访问部署好的 Wordpress 应用。

output "slb_ip" {
  value = "${kubernetes_service.wordpress.load_balancer_ingress.0.ip}"
}

variables.tf

该文件包含了部署 MySQL 和 WordPress 所依赖的参数。

variable "wordpress_version" {
  description = "The version of wordpress. Default to 4.7.3."
  default = "4.7.3"
}

variable "mysql_password" {
  description = "Please input mysql password."
}

variable "mysql_version" {
  description = "The version of mysql which wordpress used. Default to 5.6."
  default = "5.6"
}

步骤 5 执行 Wordpress Terraform 脚本

首先定位到您存放以上文件的目录，如 /root/terraform/kuberneters-wordpress。运行terraform apply 命令，开始在创建好的 Kubernetes 集群上部署 MySQL 和 WordPress 应用。

值得注意的是，由于变量 mysql_password 在变量文件中没有定义默认值，因此在执行命令是应输入参数值。

$ terraform apply -var 'mysql_password=Abc1234'

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:
...

Plan: 9 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

kubernetes_secret.mysql: Creating...
  data.%:                      "" => "1"
  data.password:               "<sensitive>" => "<sensitive>"
  metadata.#:                  "" => "1"
  metadata.0.generation:       "" => "<computed>"
  metadata.0.name:             "" => "mysql-pass"

......

Apply complete! Resources: 9 added, 0 changed, 0 destroyed.

Outputs:

slb_ip = 47.99.xx.xx

terraform apply 命令执行完毕后, 输出负载均衡 Public IP。

步骤 6 访问 WordPress

根据负载均衡 Public IP，运行如下命令或者直接在浏览器中输入 IP 地址即可实现对部署好的 Wordpress 直接访问：

open http://47.99.xx.xx

1. 进入 WordPress 欢迎页面，可选择语言，然后继续配置。

1. 输入站点名称以及管理员的用户名和密码。选择安装 WordPress。

1. WordPress 安装完成后，单击 登录，输入管理员的用户名和密码，进入 WordPress 应用。

延伸阅读

阿里云目前是 Terraform 官方的 Major Cloud Provider，如果您想通过 terraform 灵活构建阿里云上的基础设施资源，您可参见 Alicloud Provider 了解更多信息，自定义资源描述文件，快速搭建属于您的云上设施 。