Chef中的动态角色属性 [英] Dynamic Role Attributes in Chef

问题描述

我希望Chef Cookbook network_interfaces 对于我的每个节点都具有ip地址，网络掩码等的动态值。适用于我的内容如下：

I would like the Chef cookbook network_interfaces to have dynamic values for ip addresses, netmasks and alike for each of my nodes. What works for me is the following:

db_role.rb（block1）：

db_role.rb (block1):

override_attributes(
  "network_interfaces" => {
      :device => 'eth0',
      :address => '123.123.123.123',
  }
)

但这不是很动态。我的想法是将ip地址（，网络掩码等）提交给刀具引导程序上的每个节点。

But that is not very dynamic. My idea was to submit the ip address(, netmask, etc.) to each node on knife bootstrap.

然后该节点将如下所示（block2）：

The node would then look like so (block2):

{
    "normal": {
      "network_interfaces" => {
          "device" : "eth0",
          "address" : "123.123.123.123"
      }
    },
    "name": "foobar",
    "run_list": [
       "recipe[zsh]",
       "role[networking_interfaces]"
    ]
}

不幸的是， network_interfaces 食谱默认情况下不会选择这些值。我的想法是像这样在角色定义中引用block2中显示的特定于节点的属性：

Unfortunately the network_interfaces cookbook does not pick up those values by default. My idea was to reference the node specific attributes shown in block2 in the roles definition like so:

override_attributes(
  "network_interfaces" => {
      :device => node['network_interfaces']['device'],
      :address => node['network_interfaces']['address'],
  }
)

这行不通，因为它显然不是json，Chef可以无法处理角色文件中动态分配的值。

This does not work because it is not json obviously and Chef can not handle dynamically allocated values in roles files.

如何实现运行 network_interfaces 配方并传递我的节点

How can I achieve to run the network_interfaces recipe and pass my node specific values to it?

推荐答案

如果通过刀添加 normal 属性bootstrap -j…，并将 override 属性保留在角色中， override 将接管（请参见 http://docs.opscode.com/essentials_node_object_attributes_precedence.html 获取属性优先级的完整列表）。如果您在运行刀具引导程序 db_role.rb 中删除​​了 override_attributes c>，或将其更改为 default_attributes ，然后在节点属性中设置IP即可。

If you add normal attributes via knife bootstrap -j …, and leave override attributes in the role, the override will take over (see http://docs.opscode.com/essentials_node_object_attributes_precedence.html for a complete list of attribute precedence). If you have deleted override_attributes from db_role.rb before running knife bootstrap, or changed it to default_attributes, then setting IP in node attributes should have worked.

最后一个代码段将无法正常工作：角色是Chef服务器上的静态JSON文档，并且在将角色上传到服务器时，Ruby仅由刀解释一次（http：//docs.opscode .com / essentials_roles_formats.html）。您无法从角色的Ruby代码中引用节点的属性，因为它甚至在接触任何节点之前都已编译为JSON。如果您想尝试类似的方法，则需要使用自定义食谱（例如， my_network_interfaces ），其配方应类似于以下内容：

The last snippet won't work: roles are static JSON documents on the Chef server, and Ruby is only interpreted once by knife when uploading role to the server (http://docs.opscode.com/essentials_roles_formats.html). You can't refer to node's attributes from role's Ruby code, as it's compiled to JSON before it even touches any node. If you want to try a similar approach, you need to use a custom cookbook (say, my_network_interfaces) with a recipe that would look somewhat like this:

node.set['network_interface']['device'] = …
node.set['network_interface']['address'] = …
include_recipe 'network_interfaces'

这样，您将使用 network_interfaces 作为库菜谱，由您的应用程序菜谱 my_network_interfaces 调用，该菜谱实现了所需的任何逻辑。根据您的问题，我无法建议您如何计算设备和地址，因为您的示例只是尝试复制相同的属性，因此不能操作。据我了解您要实现的目标，您希望角色中有 default_attributes ，并将具有 normal 属性的特定JSON传递给刀具引导程序覆盖默认设置。

This way, you'd use network_interfaces as a "library" cookbook, called by your "application" cookbook my_network_interfaces which implements whatever logic you need. From your question, I can't suggest how would you compute device and address, as your example just tries to copy same attributes, which is a no-op. As far as I understand what you want to achieve, you want to have default_attributes in the role, and pass specific JSON with normal attributes to knife bootstrap to override the defaults.

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