Ansible 组变量优先级 [英] Ansible group vars priority

问题描述

假设我在 group_vars 中有 3 个文件:

Let's say I have 3 files in group_vars:

abc.yml
all.yml
xyz.yml

以及在它们中定义的相同变量:

And the same variable defined in them:

- my_var: abc
- my_var: all
- my_var: xyz

Ansible 文档 说:

Ansible documentation says:

在任何部分中，重新定义一个 var 都会覆盖之前的实例.如果多个组具有相同的变量，则最后加载的组获胜.如果您在一个 play 的 vars: 部分定义了两次变量，则第 2 个获胜.

Within any section, redefining a var will overwrite the previous instance. If multiple groups have the same variable, the last one loaded wins. If you define a variable twice in a play’s vars: section, the 2nd one wins.

这是否意味着加载顺序是按字母顺序排列的，abc.yml 的优先级最低，而 xyz.yml 的优先级最高，还是取决于组的顺序主机?

Does it mean that load order is alphabetical one and abc.yml has the lowest priority, whereas xyz.yml the highest, or it depends on order of groups in hosts?

加载顺序是什么?

有趣的是，改变 hosts 中组的顺序也会改变结果，但方式不可预测.

It is interesting, that changing the order of groups in hosts changes results as well, but in unpredictable way.

我尝试使用以下所有组合运行 ansible-playbook my_var.yml -c local(仅返回变量值):

I tried running ansible-playbook my_var.yml -c local (that only returns variable value) with all the combinations of:

[all]
localhost

[xyz]
localhost

[abc]
localhost

但我仍然无法弄清楚它是如何工作的.

but I still cannot figure out how it works.

推荐答案

ansible 文档现在对这种行为非常清楚...

The ansible documentation is quite clear on this behaviour now...

https://docs.ansible.com/ansible/2.6/user_guide/intro_inventory.html#how-variables-are-merged

当同一父/子级别的组合并时，按字母顺序完成，最后加载的组覆盖之前的组.例如，a_group 将与 b_group 合并，匹配的 b_group 变量将覆盖 a_group 中的变量.

When groups of the same parent/child level are merged, it is done alphabetically, and the last group loaded overwrites the previous groups. For example, an a_group will be merged with b_group and b_group vars that match will overwrite the ones in a_group.

从 Ansible 2.4 版本开始，用户可以使用组变量 ansible_group_priority 来更改同级别组的合并顺序(在父/子顺序解决后).数字越大，合并越晚，优先级越高.如果未设置，此变量默认为 1.例如:

Starting in Ansible version 2.4, users can use the group variable ansible_group_priority to change the merge order for groups of the same level (after the parent/child order is resolved). The larger the number, the later it will be merged, giving it higher priority. This variable defaults to 1 if not set. For example:

a_group:
    testvar: a
    ansible_group_priority: 10
b_group
    testvar: b

在这个例子中，如果两个组具有相同的优先级，结果通常是 testvar == b，但由于我们给 a_group 一个更高的优先级，结果将是 testvar == a.

In this example, if both groups have the same priority, the result would normally have been testvar == b, but since we are giving the a_group a higher priority the result will be testvar == a.

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