Ansible 正则表达式从 /etc/hosts 中删除匹配的 IP

Question

我正在尝试更改远程节点的主机名并且此部分有效：

- name: Change the hostname
  lineinfile: dest=/etc/hosts
              regexp='.*{{ item }}$'
              line="{{ hostvars[item].ansible_default_ipv4.address }} {{ LOCAL_HOSTNAME }} {{ LOCAL_HOSTNAME }}.{{ LOCAL_DOMAIN_NAME }}"
              state=present
  when: hostvars[item].ansible_default_ipv4.address is defined
  with_items: "{{ groups['dbservers'] }}"

因此，它会将 IP hostname FQDN 附加到 /etc/hosts 文件的末尾。

我想要实现的是删除现有条目然后添加此部分，这是我尝试过的：

    - name: Change the hostname
      lineinfile: dest=/etc/hosts
#                  regexp='.*{{ item }}$'
                  regexp='{{ hostvars[item].ansible_default_ipv4.address }}'
                  state=absent
#                  line="{{ hostvars[item].ansible_default_ipv4.address }} {{ LOCAL_HOSTNAME }} {{ LOCAL_HOSTNAME }}.{{ LOCAL_DOMAIN_NAME }}"
#                  state=present
      when: hostvars[item].ansible_default_ipv4.address is defined
      with_items: "{{ groups['dbservers'] }}"

但是，这一直显示以下错误：

The offending line appears to be:
#                  regexp='.*{{ item }}$'
                  regexp="{{ hostvars[item].ansible_default_ipv4.address }}"
                  ^ here
We could be wrong, but this one looks like it might be an issue with
missing quotes.

将引号从 '' 更改为 "" 似乎不起作用。我的问题是：

这样查询IP是否正确，以便删除主机文件中的条目？
如果是这样，有人可以指出错误句法？
有没有更高效的方法来实现去除任务（所有）现有条目，然后在 /etc/hosts?

Answer 1

您不能使用 Ansible 表示法（带等号）并将其视为 YAML。

您的代码的问题不在于引用，而在于您在不该插入注释的地方插入了注释。

以下语法有效，您的无效：

- name: Change the hostname
  lineinfile:
    dest: /etc/hosts
    # regexp: '.*{{ item }}$'
    regexp: '{{ hostvars[item].ansible_default_ipv4.address }}'
    state: absent
    # line: "{{ hostvars[item].ansible_default_ipv4.address }} {{ LOCAL_HOSTNAME }} {{ LOCAL_HOSTNAME }}.{{ LOCAL_DOMAIN_NAME }}"
    # state: present
  when: hostvars[item].ansible_default_ipv4.address is defined
  with_items: "{{ groups['dbservers'] }}"

Answer 2

Here you go..
---
- name: host trick
  hosts: dev
  gather_facts: yes
  become: true
  pre_tasks:
    - name: Include fixed env variables
      include_vars: "group_vars/dev.yml"


  tasks:

  - debug: var=hostvars[groups['app'][0]].ansible_host
  
  - name: Update the /etc/hosts file with node name
    vars: 
         remove_host: "hostname.domain.com"
    tags: etchostsupdate
    become: yes
    become_user: root
    lineinfile:
      dest: /etc/hosts
      regexp: "{{ remove_host }}"
      line: "{{ hostvars[item]['ansible_default_ipv4']['address'] }} {{item}}"
      state: absent
      backup: yes
    register: etchostsupdate
    when: hostvars[item]['ansible_facts']['default_ipv4'] is defined
    with_items:
      - "{{ groups['dev'] }}"



#ansible-playbook -i dev/hosts dev/remove_etc_hosts.yml -e "remove_host=hostname.domain.com"

Ansible 正则表达式从 /etc/hosts 中删除匹配的 IP

Ansible regex to delete matching IPs from /etc/hosts

regex

linux

ansible

devops