Ansible中替换模块介绍

ansible在使用sed进行替换时，经常会遇到需要转义的问题，而且ansible在遇到特殊符号进行替换时，存在问题，无法正常进行替换 。其实在ansible自身提供了两个模块－－－lineinfile模块和replace模块，可以方便的进行替换 。这里以使用ansilble安装salt-minion为例，用如下playbook语句执行时，是执行不成功的：

shell: sed -i '/^#id:/a/id: {{ ansible_ens192.ipv4.address }}' /etc/salt/minion

由于上面的语名里特殊符号比较多，多次转义测试不成功。同样直接调用shell 模块时也会遇到这样问题，比如这里有一个将/etc/hosts最后一行注释的语句，使用$s 变量时会不成功，需要通过 /进行转义 。

ansible all -m shell -a "sed -e '$s/^/#/g' /etc/hosts" //不成功
ansible all -m shell -a "sed -i '/$s/#//g' /etc/hosts" //成功

接下来我们看下ansilbe自的替换模块。

ansible-doc帮助信息给我们的示例如下：

- lineinfile: dest=/etc/selinux/config regexp=^SELINUX= line=SELINUX=enforcing 行替换
- lineinfile: dest=/etc/sudoers state=absent regexp="^%wheel" 行删除
- lineinfile: dest=/etc/hosts regexp='^127/.0/.0/.1' line='127.0.0.1 localhost' owner=root group=root mode=0644
- lineinfile: dest=/etc/httpd/conf/httpd.conf regexp="^Listen " insertafter="^#Listen " line="Listen 8080" 将以?#Listen?开头行的下面的?以Listen开头的行换成
- lineinfile: dest=/etc/services regexp="^# port for http" insertbefore="^www.*80/tcp" line="# port for http by default"
# Add a line to a file if it does not exist, without passing regexp
- lineinfile: dest=/tmp/testfile line="192.168.1.99 foo.lab.net foo"
# Fully quoted because of the ': ' on the line. See the Gotchas in the YAML docs.
- lineinfile: "dest=/etc/sudoers state=present regexp='^%wheel' line='%wheel ALL=(ALL) NOPASSWD: ALL'"
- lineinfile: dest=/opt/jboss-as/bin/standalone.conf regexp='^(.*)Xms(/d+)m(.*)$' line='/1Xms${xms}m/3' backrefs=yes
# Validate the sudoers file before saving
- lineinfile: dest=/etc/sudoers state=present regexp='^%ADMIN ALL/=' line='%ADMIN ALL=(ALL) NOPASSWD:ALL' validate='visudo -cf %s'

该模块有点类似于sed命令，主要也是基于正则进行匹配和替换，如下：

- replace: dest=/etc/hosts regexp='(/s+)old/.host/.name(/s+.*)?$' replace='/1new.host.name/2' backup=yes
- replace: dest=/home/jdoe/.ssh/known_hosts regexp='^old/.host/.name[^/n]*/n' owner=jdoe group=jdoe mode=644
- replace: dest=/etc/apache/ports regexp='^(NameVirtualHost|Listen)/s+80/s*$' replace='/1 127.0.0.1:8080' validate='/usr/sbin/apache2ctl -f %s -t'

回到原来的问题，使用ansible安装salt-minion涉及到的替换问题，这里用的playbook最后的修改结果如下：

- name: Fetch configuration from all testservers ，code from www.361way.com
hosts: all
vars:
ID: "id:"
masterip: "master: 10.211.95.232"
tasks:
- name: copy migu repo to hosts
copy: src=./file/migu_rhel7.repo dest=/etc/yum.repos.d/migumirror.repo
- name: install salt repo
yum: name=https://repo.saltstack.com/yum/redhat/salt-repo-latest-2.el7.noarch.rpm state=present
- name: install salt minion
yum: name=salt-minion state=latest
- name: set the salt master ip
shell: echo {{ masterip }} >>/etc/salt/minion
- name: Get config
#shell: sed -i '/^#id:/a/id: {{ ansible_ens192.ipv4.address }}' /etc/salt/minion
lineinfile: dest=/etc/salt/minion regexp="^#id" line="{{ ID }} {{ inventory_hostname }}"
- name: enable and start minion
shell: "systemctl enable salt-minion.service && systemctl start salt-minion.service"