如何使用ansible更新文件中的新主机名？

Question

I am using below code to replace old hostname with new one, it is working except for hostnames starting with numbers.(OLD_HOSTNAME and NEW_HOSTNAME are vars )

  tasks:
  - name: "Updating file"
    replace:
      name: /tmp/interfaces
      backup: yes
      regexp: '(\s+){{ OLD_HOSTNAME }}(\s+)'
      replace: '\1{{ NEW_HOSTNAME }}\2'

If I replace \\1 with \\g<1> , the hostnames starting with numbers will also get placed. But as per the ansible doc , \\1 is used ambiguously , and \\g<1> used explicitly .

Question: Will this change impact any other format of hostname?

Answer 1

No, using the explicit form will not affect other hostname formats.

The reason why you have a problem when NEW_HOSTNAME begins with a number is that the replace string would become something like \\123-server\\2 if NEW_HOSTNAME was 23-server and there is no backreference \\123 . Using the explicit form preserves your original intent. In my example, replace would become \\g<1>23-server\\g<2> .