如何使用 Ansible Playbook 遍历主机的 N 级子级?

问题描述

我知道如何使用 host_vars 实现这一点，但它的问题是主机文件可能会变得复杂，所以我倾向于使用 ini 文件，我可以在其中放置所有一个文件中的数据.这个 SO 帖子帮助我一个想法如何将集合放入特定主机的变量中.

I know how to achieve this using host_vars but the problem with it is the host files can get convoluted so I'm leaning towards ini files where I can put all the data in one file. This SO post helped me have an idea how to put a collection in a variable for a particular host.

我有这个样本库存:

;hosts.yml
[web1]
example1.com databases=["example1_com","mysql"]
example2.com databases=["example1_com","mysql"]

[web1:vars]
ansible_host=10.0.16.21

[web2]
example3.com databases=["example3_com"]
example4.com databases=["example4_com","mysql"]

[web2:vars]
ansible_host=10.0.16.22

[web:children]
web1
web2

现在我想使用 web 组遍历每个主机并遍历 databases 主机变量.

Now I wanted to loop through each hosts using the the web group and iterate through the databases host var.

我做了这样的事情:

---
- debug:
    msg: "{{ item }} - {{ hostvars[item]['databases'] }} "
  with_items:
    - "{{ groups['web'] }}"

输出为:

ok: [localhost] => (item=example1.com) => {
    "item": "example1.com", 
    "msg": "example1.com - [example1_com,mysql] "
}
ok: [localhost] => (item=example2.com) => {
    "item": "example2.com", 
    "msg": "example2.com - [example1_com,mysql] "
}
ok: [localhost] => (item=example3.com) => {
    "item": "example3.com", 
    "msg": "example3.com - [example3_com] "
}
ok: [localhost] => (item=example4.com) => {
    "item": "example4.com", 
    "msg": "example4.com - [example4_com,mysql] "
}

我尝试使用 with_sublements 循环来实现这一点，但问题是第二个元素需要是动态的，而 with_subelements 是不可能的.

I tried achieving this using with_sublements loop but the problem is the 2nd element needs to be dynamic which is not possible with_subelements.

with_subelements:
    - "{{ groups['web'] }}"
    - {{ hostvars[item]['databases'] }} #item is dynamic, this will cause an undefined host error.

推荐答案

我不是 100% 清楚您的原始方法是什么，以及您问题中的代码是否旨在代表您的新方法(因为您仍在参考hostvars 那里).我认为您需要在运行 playbook 时在 playbook (hosts: web) 或命令行 (-l web) 中指定要影响的组只为您想要的那些主机运行任务，而不是尝试在任务本身内动态获取组.

It's not 100% clear to me what your original approach was, and if the code in your question was meant to represent your new approach (since you are still referencing hostvars there). I think you need to work more with specifying the groups you want affected within the playbook (hosts: web) or on the command line (-l web) when running the playbook to run the tasks only for those hosts you want, rather than trying to get the group dynamically within the task itself.

关于链接的问题/答案，其中讨论了在变量中定义列表的方法:您需要确保将列表数据括在单引号中，例如'["example1_com","mysql"]'.

Regarding the linked question/answer, where a way of defining a list within a variable was discussed: you need to make sure to enclose the list data within single quotes, e.g. '["example1_com","mysql"]'.

鉴于此，如果您只是想从清单文件中定义的主机变量中迭代列表，您可以执行以下操作:

Given that, if you simply want to iterate over a list from a host variable defined in an inventory file, you can do the following:

库存文件inv"

[web1]
example1.com databases='["example1_com","mysql"]'
example2.com databases='["example1_com","mysql"]'

[web1:vars]
ansible_host=10.0.16.21

[web2]
example3.com databases='["example3_com"]'
example4.com databases='["example4_com","mysql"]'

[web2:vars]
ansible_host=10.0.16.22

[web:children]
web1
web2

剧本文件test.yml"

---
- hosts: web
  gather_facts: no
  tasks:
    - debug: msg="Host is {{ inventory_hostname }}. Database is {{ item }}"
      with_items:
        - "{{ databases }}"

然后您可以运行剧本:

ansible-playbook test.yml -i inv

生成以下输出:

PLAY ***************************************************************************

TASK [debug] *******************************************************************
ok: [example3.com] => (item=example3_com) => {
    "item": "example3_com", 
    "msg": "Host is example3.com. Database is example3_com"
}
ok: [example1.com] => (item=example1_com) => {
    "item": "example1_com", 
    "msg": "Host is example1.com. Database is example1_com"
}
ok: [example1.com] => (item=mysql) => {
    "item": "mysql", 
    "msg": "Host is example1.com. Database is mysql"
}
ok: [example2.com] => (item=example1_com) => {
    "item": "example1_com", 
    "msg": "Host is example2.com. Database is example1_com"
}
ok: [example2.com] => (item=mysql) => {
    "item": "mysql", 
    "msg": "Host is example2.com. Database is mysql"
}
ok: [example4.com] => (item=example4_com) => {
    "item": "example4_com", 
    "msg": "Host is example4.com. Database is example4_com"
}
ok: [example4.com] => (item=mysql) => {
    "item": "mysql", 
    "msg": "Host is example4.com. Database is mysql"
}

PLAY RECAP *********************************************************************
example1.com               : ok=1    changed=0    unreachable=0    failed=0   
example2.com               : ok=1    changed=0    unreachable=0    failed=0   
example3.com               : ok=1    changed=0    unreachable=0    failed=0   
example4.com               : ok=1    changed=0    unreachable=0    failed=0   

如果您正确构建您的剧本，您还可以将其设置为为不同的主机组运行不同的任务集(可能包括来自外部文件的任务，以便您 DRY).或者，您可以简单地在剧本中指定 hosts: all，并使用命令行限制仅针对特定的一组主机运行任务.

If you properly structure your playbook, you can also set it up to run different sets of tasks for different host groups (perhaps including the tasks from an external file so you DRY). Or you could simply specify hosts: all in the playbook, and use command line limiting to only run the tasks against a specific set of hosts.

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