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【Terraform】快速实践"Hello World"
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小知识，大挑战！本文正在参与“程序员必备小知识”创作活动。 本文同时参与 「掘力星计划」 ，赢取创作大礼包，挑战创作激励金。 专栏上文已经简单介绍了Terraform以及其安装，这篇文章根据社区教程，编写一个基于Docker启动nginx的例子。 一、环境准备Terraform 和 Docker 在正式开始例子之前，我们必须保证环境中已经安装了Terraform、docker，前者参照专栏内部的上篇文章，docker的安装参照这篇文章《文章TODO》。 Provider插件缓存配置 在Terraform的整个执行流程中，我们在使用到Terraform init命令时，该工具会分析我们代码中使用到的Provider，并尝试下载Provider插件到本地，如果我们不进行特殊的设置，每次执行init都会尝试去下载插件，并且每个项目都回保存自己独立的插件，相当浪费空间。这怎么办呢？ 这时我们可以使用插件缓存,基本的原理只要插件下载成功一次，就会保存在指定的插件缓存目录，其它项目再次下载，就会拷贝缓存内容到项目目录，甚至在系统支持上，Terraform还会使用符号连接这个缓存路径，并不直接拷贝插件内容。 有两种方式，第一种方式是配置TF_PLUGIN_CACHE_DIR环境变量： #务必确保这个目录下已经创建好plugin-cache这个文件夹 export TF_PLUGIN_CACHE_DIR="$HOME/.terraform.d/plugin-cache" 复制代码第二种方式是使用CLI配置文件，基于Linux环境，在用户的/home目录下创建名为 ".terraformrc" 的文件： plugin_cache_dir = "$HOME/.terraform.d/plugin-cache" 复制代码需要注意的是：有必要关注缓存路径的空间增长，择机选择性地手工清理不必要的Provider插件。 二、实战这次实战的目的是通过Terraform部署基于Docker的Nginx环境，并能成功访问到Nginx的欢迎主页。 2.1 定义资源在这里我们使用到Github上的项目 [terraform-provider-docker] github.com/kreuzwerker… 提供的Provider插件，编写资源文件main.tf。 terraform { #定义所需的Provider required_providers { docker = { source = "kreuzwerker/docker" version = "~> 2.13.0" } } } # 配置docker provider provider "docker" {} #创建一个docker镜像资源 resource "docker_image" "nginx" { name = "nginx:latest" keep_locally = false } #创建一个docker容器资源 #这部分的资源定义，类似"docker run --name nginx -p8080:80 -d nginx:latest" resource "docker_container" "nginx" { image = docker_image.nginx.latest name = "tutorial" ports { internal = 80 external = 8000 } } #接下来还可以继续定义服务资源 复制代码 2.2 执行创建关于基础设施的资源已经定义完成，接下来就是在安装好Terraform和docker的服务器上执行部署。 首先，为了区分项目，达到隔离资源的目的，我们先在工程目录创建一个新文件夹： #创建目录 $mkdir learn-terraform-docker-container #进入目录 $cd learn-terraform-docker-container 复制代码然后上传main.tf到当前文件夹。接着在当前目录执行Terraform init初始化环境。 $Terraform init 复制代码小提示：环境初始过程花费的时间会与你的服务器网络环境密切相关，请耐心等待，如果失败，请多尝试几次！ 如图上所示，环境初始化成功，观察本地目录，多了一些文件和文件夹。
接下来，我们预览资源部署情况terraform plan。 $terraform plan 复制代码执行结果输出如下： Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: + create Terraform will perform the following actions: # docker_container.nginx will be created + resource "docker_container" "nginx" { + attach = false + bridge = (known after apply) + command = (known after apply) + container_logs = (known after apply) + entrypoint = (known after apply) + env = (known after apply) + exit_code = (known after apply) + gateway = (known after apply) + hostname = (known after apply) + id = (known after apply) + image = (known after apply) + init = (known after apply) + ip_address = (known after apply) + ip_prefix_length = (known after apply) + ipc_mode = (known after apply) + log_driver = "json-file" + logs = false + must_run = true + name = "tutorial" + network_data = (known after apply) + read_only = false + remove_volumes = true + restart = "no" + rm = false + security_opts = (known after apply) + shm_size = (known after apply) + start = true + stdin_open = false + tty = false + healthcheck { + interval = (known after apply) + retries = (known after apply) + start_period = (known after apply) + test = (known after apply) + timeout = (known after apply) } + labels { + label = (known after apply) + value = (known after apply) } + ports { + external = 8000 + internal = 80 + ip = "0.0.0.0" + protocol = "tcp" } } # docker_image.nginx will be created + resource "docker_image" "nginx" { + id = (known after apply) + keep_locally = false + latest = (known after apply) + name = "nginx:latest" + output = (known after apply) + repo_digest = (known after apply) } Plan: 2 to add, 0 to change, 0 to destroy. 复制代码根据输出内容可以看到增加了两个资源，包括镜像和容器。无更改和销毁项。 接下来执行部署资源terraform apply。 $terraform apply 复制代码执行结果输出如下： Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: + create Terraform will perform the following actions: # docker_container.nginx will be created + resource "docker_container" "nginx" { + attach = false + bridge = (known after apply) + command = (known after apply) + container_logs = (known after apply) + entrypoint = (known after apply) + env = (known after apply) + exit_code = (known after apply) + gateway = (known after apply) + hostname = (known after apply) + id = (known after apply) + image = (known after apply) + init = (known after apply) + ip_address = (known after apply) + ip_prefix_length = (known after apply) + ipc_mode = (known after apply) + log_driver = "json-file" + logs = false + must_run = true + name = "tutorial" + network_data = (known after apply) + read_only = false + remove_volumes = true + restart = "no" + rm = false + security_opts = (known after apply) + shm_size = (known after apply) + start = true + stdin_open = false + tty = false + healthcheck { + interval = (known after apply) + retries = (known after apply) + start_period = (known after apply) + test = (known after apply) + timeout = (known after apply) } + labels { + label = (known after apply) + value = (known after apply) } + ports { + external = 8000 + internal = 80 + ip = "0.0.0.0" + protocol = "tcp" } } # docker_image.nginx will be created + resource "docker_image" "nginx" { + id = (known after apply) + keep_locally = false + latest = (known after apply) + name = "nginx:latest" + output = (known after apply) + repo_digest = (known after apply) } Plan: 2 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 复制代码输入yes明确要执行部署。 部署完成！未出现错误。 然后查看docker容器中是否已经创建了nginx。 $docker ps 复制代码有了，创建成功了，然后curl访问一下，也能获取到欢迎主页！ 至此，部署创建成功，我们观察项目目录，多了一个terraform.tfstate文件，这个就是状态文件，相当重要，切记不要尝试去手动修改它！ 2.3 执行销毁执行销毁那是相当简单了，用项目目录下执行terraform destroy命令即可。 $terraform destroy 复制代码 |
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