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puppet dynamic environment

July 6, 2014

puppet environment

puppet environment是独立的puppet环境，每个环境有自己的modules和manifests目录。agent可以在配置文件或者命令行指定自己要哪个环境的配置。

如agent运行:

$ puppet agent --environment testing

那么就应用testing环境的配置。

puppet dynamic environment

puppet静态环境是指以下配置：

[main]
  server = puppet.example.com
  environment = production
  confdir = /etc/puppet
[agent]
  report = true
  show_diff = true
[production]
  manifest = /etc/puppet/environments/production/manifests/site.pp
  modulepath = /etc/puppet/environments/production/modules
[testing]
  manifest = /etc/puppet/environments/testing/manifests/site.pp
  modulepath = /etc/puppet/environments/testing/modules
[development]
  manifest = /etc/puppet/environments/development/manifests/site.pp
  modulepath = /etc/puppet/environments/development/modules

对于每个环境，都要在puppet.conf里有一个配置项，相比之下，使用fact变量$environment的配置就是动态的：

    [main]
      server = puppet.example.com
      environment = production
      confdir = /etc/puppet
    [master]
      environment = production
      manifest    = $confdir/environments/$environment/manifests/site.pp
      modulepath  = $confdir/environments/$environment/modules
    [agent]
      report = true
      show_diff = true
      environment = production

puppet v3.5.0以后，配置更为简单：

    [main]
      environmentpath = $confdir/environments 这种只指定目录的设计具有扩展性，用户可以随意增加和删除环境，只需要在$confdir/environments目录下创建目录和删除目录就可以了，而不用改puppet.conf，这也使得自动部署变得方便。

puppet动态环境的自动部署

利用post-receive hook。工作流程是开发者git clone puppet仓库，新建分支，如my_feature，然后git push。有了那个post-receive hook，远程仓库收到push请求，会ssh到puppet master所在的机器，在$confdir/environments/目录下新建目录my_feature，然后把my_feature分支里的内容clone过来。

使用gitlab的Webhooks自动部署实质也是post-receive，只是webhooks的接口是url post请求，所以需要写个小服务器。