从Ansible中的查找中创建常量
从Ansible中的查找中创建常量
提问于 2021-08-19 14:50:56
我正在尝试从Ansible中的查找中创建一个变量。然后，我想在角色的其余部分中使用该变量作为常量。下面是来自defaults/main.yml的几行代码。
job_start_time: "{{ lookup('pipe','date +%Y%m%d_%H%M%S') }}"
new_virtual_machine_name: "{{ template_name }}-pkrclone-{{ job_start_time }}"当new_virtual_machine_name变量在tasks/main.yml中使用时，运行角色的结果会导致一个错误，因为查找会再次发生。您可以看到后续任务中的第二个增量。
TASK [update_vsphere_template : Write vsphere source file] changed: [localhost] => {"changed": true, "checksum": "c2ee7ed6fad0b26aea825233f3e714862de3ac28", "dest": "packer-DevOps-Windows2019-Base-DevOps-Windows2019-Base-pkrclone-20210819_**093122**/vsphere-source-DevOps-Windows2019-Base-DevOps-Windows2019-Base-pkrclone-20210819_**093122**.pkr.hcl", 148765781020136/source", "state": "file", "uid": 1000}
TASK [update_vsphere_template : Write the template update file] *fatal: [localhost]: FAILED! => {"changed": false, "checksum": "6fd97c1d2373b9c71ad6b5246529c46a38f55c48", "msg": "Destination directory packer-DevOps-Windows2019-Base-DevOps-Windows2019-Base-pkrclone-20210819_**093123** does not exist"}下面是如何在new_virtual_machine_name中引用tasks/main.yml变量
- name: Write vsphere source file
template:
src: ../templates/vsphere-source.j2
dest: 'packer-{{template_name}}-{{ new_virtual_machine_name }}/vsphere-source-{{ template_name }}-{{ new_virtual_machine_name }}.pkr.hcl'
- name: Write the template update file
template:
src: ../templates/update-template.j2
dest: 'packer-{{template_name}}-{{ new_virtual_machine_name }}/update-{{ template_name }}-{{ new_virtual_machine_name }}.pkr.hcl'在每次引用作业开始时从查找中创建的变量时，我如何防止Ansible运行查找？谢谢。
回答 2
Stack Overflow用户
回答已采纳
发布于 2021-08-19 15:48:30
问：“每次引用变量时，如何防止Ansible运行查找？”
答:使用绞合时间，每次调用过滤器时，您都会得到当前的日期。
- set_fact:
job_start_time: "{{ '%Y%m%d_%H%M%S'|strftime }}"
- debug:
msg: "pkrclone-{{ job_start_time }}"
- wait_for:
timeout: 3
- debug:
msg: "pkrclone-{{ job_start_time }}"
- set_fact:
job_start_time: "{{ '%Y%m%d_%H%M%S'|strftime }}"
- debug:
msg: "pkrclone-{{ job_start_time }}"给出
msg: pkrclone-20210819_174748
msg: pkrclone-20210819_174748
msg: pkrclone-20210819_174753Stack Overflow用户
发布于 2021-08-19 15:29:41
是的，每次调用变量时都会对它们进行评估。解决这一问题的一种方法是使用set_facts来存储一个事实，这个事实只在被设置并存储为主机的静态值时才会被评估。
编辑：注意到，正如@的答案(并在评论中讨论过的)所指出的，使用pipe查找获取这样的信息并不是一个很好的实践，如果您在核心Ansible中使用了strftime过滤器。所以我在下面的例子中改变了它。
为了说明这一点，请看以下剧本：
---
- hosts: localhost
gather_facts: false
vars:
_job_start_time: "{{ '%Y%m%d_%H%M%S'| strftime }}"
tasks:
- name: Force var into a fact that will be constant throughout play
set_fact:
job_start_time: "{{ _job_start_time }}"
- name: Wait a bit making sure time goes on
pause:
seconds: 1
- name: Show that fact is constant whereas inital var changes
debug:
msg: "var is: {{ _job_start_time }}, fact is: {{ job_start_time }}"
- name: Wait a bit making sure time goes on
pause:
seconds: 1
- name: Show that fact is constant whereas inital var changes
debug:
msg: "var is: {{ _job_start_time }}, fact is: {{ job_start_time }}"给予：
PLAY [localhost] ***********************************************************************************************************************************************************************************************************************
TASK [Force var into a fact that will be constant throughout play] *********************************************************************************************************************************************************************
ok: [localhost]
TASK [Wait a bit making sure time goes on] *********************************************************************************************************************************************************************************************
Pausing for 1 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
ok: [localhost]
TASK [Show that fact is constant whereas inital var changes] ***************************************************************************************************************************************************************************
ok: [localhost] => {
"msg": "var is: 20210819_172528, fact is: 20210819_172527"
}
TASK [Wait a bit making sure time goes on] *********************************************************************************************************************************************************************************************
Pausing for 1 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
ok: [localhost]
TASK [Show that fact is constant whereas inital var changes] ***************************************************************************************************************************************************************************
ok: [localhost] => {
"msg": "var is: 20210819_172529, fact is: 20210819_172527"
}
PLAY RECAP *****************************************************************************************************************************************************************************************************************************
localhost : ok=5 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/68850093
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