Ansible - 高级Shell命令执行格式

Question

Ansible - 高级Shell命令执行格式

5

我有3个变量名称为IPOctet、ServerIPRange和epcrange。如果我在终端中执行以下操作，它将完美地工作：

IPOctet=$(echo "$ServerIPRange/$epcrange+$IPOctet" | bc)

如何在Ansible任务中实现类似的操作，例如：

---
- hosts: localhost
  gather_facts: False

  vars_prompt:
    - name: epcrange
      prompt: Enter the number of EPCs that you want to configure
      private: False
      default: "1"
    - name: serverrange
      prompt: Enter the number of Clients that you want to configure
      private: False
      default: "1"
    - name: ServerIPRange
      prompt: Enter the ServerIP range
      private: False
      default: '128'
    - name: LastIPOctet
      prompt: Enter The last Octet of the IP you just entered
      private: False
      default: '10'

  pre_tasks:


    - name: Set some facts
      set_fact:
        ServerIP1: "{{ServerIP}}"
        ServerIPRange1: "{{ServerIPRange}}"
        IPOctet: "{{LastIPOctet}}"

    - name: local action math
      local_action: shell {{IPOctet}}=$(echo "${{ServerIPRange}}/${{epcrange}}+${{IPOctet}}" | bc)  # Proper Syntax?
      with_sequence: start=1 end=4
      register: result
      ignore_errors: yes

这个命令的正确语法是什么？也许可以使用shell echo "......."。我只需要将此命令的内容保存到IPOctet变量中，IPOctet将在每个循环迭代中更改，结果应该存储在我的结果寄存器中。

附注：如何单独访问数组中的各个项？

编辑：是否有类似这样的东西？目前它只会计算一次，并将其4次存储在寄存器中...

- name: bashless math
  set_fact:
    IPOctet: "{{ (ServerIPRange|int/epcrange|int)+IPOctet|int }}"
  register: IPOctet
  with_sequence: "start=1 end={{stop}} "
  register: my_ip_octet

- Khan

2个回答

2

首先，你的Jinja模板有误，每个变量都需要用一对花括号括起来。你不能在单个花括号中使用多个变量。例如，

{{ ServerIPRange }}

其次，set_fact仅用于设置事实值。您不能使用set_fact运行shell命令。您应该使用shell模块。

- name: local action math
  local_action: shell {{ IPOctet }}=$(echo {{ ServerIPRange|int }}/{{ epcrange|int }}+{{ IPOctet|int }}" | bc)
  with_sequence: start=1 end=4
  register: result
  ignore_errors: yes

Ansible会进行4次计算，并将结果存储在一个列表中，作为四个不同的元素。您可以检查此列表中存储的所有内容，甚至可以通过循环访问它。

- debug: msg={{ result }}

希望这能帮到你 :)

- Ramesh Raithatha

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- Derek Baum · Accepted Answer

Your terminal expression reassigns the IPOctet shell variable, so it gives a different result each time it is executed. This is fine, but difficult to reproduce in Ansible:

$ IPOctet=10 ServerIPRange=128 epcrange=1
$ IPOctet=$(echo "$ServerIPRange/$epcrange+$IPOctet" | bc); echo $IPOctet
138

$ IPOctet=$(echo "$ServerIPRange/$epcrange+$IPOctet" | bc); echo $IPOctet
266

The syntax: "shell {{IPOctet}}=$(echo ..." does NOT assign to the Ansible variable. The shell attempts to execute a command like "10=138", which is not found.
When register is used within a loop, the target variable is not set until the loop completes - so your expression always sees the original value for {{IPOctet}}.

A solution is to run the whole loop as a single shell command:

- name: local action math2
  local_action: shell IPOctet={{IPOctet}}; for i in 1 2 3 4; do IPOctet=$(expr {{ServerIPRange}} / {{epcrange}} + $IPOctet); echo $IPOctet; done
  register: result

NOTE: I've used the expr command rather than bc, but the results are the same.

You can iterate over these results using result.stdout_lines:

- name: iterate results
  local_action: debug msg={{item}}
  with_items: result.stdout_lines