ansible 条件判断+循环

条件判断
When 语句
在when 后面使用Jinja2 表达式，结果为True则执行任务。
tasks:  - name: "shut down Debian flavored systems"    command: /sbin/shutdown -t now    when: ansible_os_family == "Debian"
若操作系统是Debian 时就执行关机操作
可以对条件进行分组在比较。
tasks:  - name: "shut down CentOS 6 and Debian 7 systems"    command: /sbin/shutdown -t now    when: (ansible_distribution == "CentOS" and ansible_distribution_major_version == "6") or          (ansible_distribution == "Debian" and ansible_distribution_major_version == "7")
可以使用列表形式来表示条件为and的关系
tasks:  - name: "shut down CentOS 6 systems"    command: /sbin/shutdown -t now    when:      - ansible_distribution == "CentOS"      - ansible_distribution_major_version == "6"
使用jinja2过滤器
tasks:  - command: /bin/false    register: result    ignore_errors: True  - command: /bin/something    when: result|failed  - command: /bin/something_else    when: result|succeeded  - command: /bin/still/something_else    when: result|skipped
忽略一个语句的错误，然后决定基于成功或失败有条件地做一些事情。
字符串转换为数字型再去比较
tasks:  - shell: echo "only on Red Hat 6, derivatives, and later"    when: ansible_os_family == "RedHat" and ansible_lsb.major_release|int >= 6
使用变量进行判断
vars:  epic: truetasks:    - shell: echo "This certainly is epic!"      when: epictasks:    - shell: echo "This certainly isn't epic!"      when: not epic
判断变量是否定义
tasks:    - shell: echo "I've got '{{ foo }}' and am not afraid to use it!"      when: foo is defined    - fail: msg="Bailing out. this play requires 'bar'"      when: bar is undefined
与循环一起使用
tasks:    - command: echo {{ item }}      with_items: [ 0, 2, 4, 6, 8, 10 ]      when: item > 5
依次遍历列表，当列表里得数字大于5时执行任务
- command: echo {{ item }}  with_items: "{{ mylist|default([]) }}"  when: item > 5- command: echo {{ item.key }}  with_dict: "{{ mydict|default({}) }}"  when: item.value > 5
当变量不存在时，直接跳过
使用自定义的facts值做判断
tasks:    - name: gather site specific fact data      action: site_facts    - command: /usr/bin/thingy      when: my_custom_fact_just_retrieved_from_the_remote_system == '1234'
角色包含使用when
- include: tasks/sometasks.yml  when: "'reticulating splines' in output"- hosts: webservers  roles:     - { role: debian_stock_config, when: ansible_os_family == 'Debian' }
基于变量选择文件和模板
- name: template a file  template: src={{ item }} dest=/etc/myapp/foo.conf  with_first_found:    - files:       - {{ ansible_distribution }}.conf       - default.conf      paths:       - search_location_one/somedir/       - /opt/other_location/somedir/
使用注册变量判断
- name: test play  hosts: all  tasks:      - shell: cat /etc/motd        register: motd_contents      - shell: echo "motd contains the word hi"        when: motd_contents.stdout.find('hi') != -1
failed_when
满足条件时，使任务失败
  tasks:    - command: echo faild.      register: command_result      failed_when: "'faild' in command_result.stdout"   - debug: msg="echo test"
还可以写成这样
  tasks:    - command: echo faild.      register: command_result      ignore_errors: True    - name: fail the echo      fail: msg="the command failed"      when: "'faild' in command_result.stdout"    - debug: msg="echo test"
changed_when
更改任务的状态。
- name: Install dependencies via Composer.  command: "/usr/local/bin/composer global require phpunit/phpunit --prefer-dist"  register: composer  changed_when: "'Nothing to install or update' not in composer.stdout"
当使用PHP Composer作为安装项目依赖项的命令时，知道什么时候是有用的Composer安装了一些东西，或什么都没有改变。
循环
标准循环
添加多个用户
- name: add several users  user: name={{ item }} state=present groups=wheel  with_items:     - testuser1     - testuser2
添加多个用户，并将用户加入不同的组内。
- name: add several users  user: name={{ item.name }} state=present groups={{ item.groups }}  with_items:    - { name: 'testuser1', groups: 'wheel' }    - { name: 'testuser2', groups: 'root' }
嵌套循环
分别给用户授予3个数据库的所有权限
- name: give users access to multiple databases  mysql_user: name={{ item[0] }} priv={{ item[1] }}.*:ALL append_privs=yes password=foo  with_nested:    - [ 'alice', 'bob' ]    - [ 'clientdb', 'employeedb', 'providerdb' ]
遍历字典
输出用户的姓名和电话
 tasks:  - name: Print phone records    debug: msg="User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})"    with_dict: {'alice':{'name':'Alice Appleworth', 'telephone':'123-456-789'},'bob':{'name':'Bob Bananarama', 'telephone':'987-654-3210'} }
并行遍历列表
  tasks:  - debug: "msg={{ item.0 }} and {{ item.1 }}"    with_together:    - [ 'a', 'b', 'c', 'd','e' ]    - [ 1, 2, 3, 4 ]
如果列表数目不匹配，用None补全
遍历列表和索引
  - name: indexed loop demo    debug: "msg='at array position {{ item.0 }} there is a value {{ item.1 }}'"    with_indexed_items: [1,2,3,4]
 item.0 为索引，item.1为值
遍历文件列表的内容
---- hosts: all  tasks:       - debug: "msg={{ item }}"      with_file:        - first_example_file        - second_example_file
遍历目录文件
with_fileglob匹配单个目录中的所有文件，非递归匹配模式。
---- hosts: all  tasks:    - file: dest=/etc/fooapp state=directory    - copy: src={{ item }} dest=/etc/fooapp/ owner=root mode=600      with_fileglob:        - /playbooks/files/fooapp/*
当在role中使用with_fileglob的相对路径时，Ansible解析相对于roles/<rolename>/files目录的路径。
遍历ini文件
lookup.ini[section1]value1=section1/value1value2=section1/value2[section2]value1=section2/value1value2=section2/value2
- debug: msg="{{ item }}"  with_ini: value[1-2] section=section1 file=lookup.ini re=true
获取section1 里的value1和value2的值
重试循环 until
- action: shell /usr/bin/foo  register: result  until: result.stdout.find("all systems go") != -1  retries: 5  delay: 10
"重试次数retries" 的默认值为3，"delay"为5。
查找第一个匹配文件
  tasks:  - debug: "msg={{ item }}"    with_first_found:     - "/tmp/a"     - "/tmp/b"     - "/tmp/default.conf"
依次寻找列表中的文件，找到就返回。如果列表中的文件都找不到，任务会报错。
随机选择with_random_choice
随机选择列表中得一个值
- debug: msg={{ item }}  with_random_choice:     - "go through the door"     - "drink from the goblet"     - "press the red button"     - "do nothing"
循环程序的结果
  tasks:  - debug: "msg={{ item }}"    with_lines: ps aux
循环子元素
定义好变量
#varfile---users:  - name: alice    authorized:      - /tmp/alice/onekey.pub      - /tmp/alice/twokey.pub    mysql:        password: mysql-password        hosts:          - "%"          - "127.0.0.1"          - "::1"          - "localhost"        privs:          - "*.*:SELECT"          - "DB1.*:ALL"  - name: bob    authorized:      - /tmp/bob/id_rsa.pub    mysql:        password: other-mysql-password        hosts:          - "db1"        privs:          - "*.*:SELECT"          - "DB2.*:ALL"
---- hosts: web  vars_files: varfile  tasks:  - user: name={{ item.name }} state=present generate_ssh_key=yes    with_items: "{{ users }}"  - authorized_key: "user={{ item.0.name }} key='{{ lookup('file', item.1) }}'"    with_subelements:      - "{{ users }}"      - authorized  - name: Setup MySQL users    mysql_user: name={{ item.0.name }} password={{ item.0.mysql.password }} host={{ item.1 }} priv={{ item.0.mysql.privs | join('/') }}    with_subelements:      - "{{ users }}"      - mysql.hosts
{{ lookup('file', item.1) }}  是查看item.1文件的内容
  with_subelements 遍历哈希列表，然后遍历列表中的给定（嵌套）的键。
在序列中循环with_sequence
with_sequence以递增的数字顺序生成项序列。 您可以指定开始，结束和可选步骤值。
参数应在key = value对中指定。 'format'是一个printf风格字符串。
数字值可以以十进制，十六进制（0x3f8）或八进制（0600）指定。 不支持负数。
---- hosts: all  tasks:    # 创建组    - group: name=evens state=present    - group: name=odds state=present    # 创建格式为testuser%02x 的0-32 序列的用户    - user: name={{ item }} state=present groups=evens      with_sequence: start=0 end=32 format=testuser%02x    # 创建4-16之间得偶数命名的文件    - file: dest=/var/stuff/{{ item }} state=directory      with_sequence: start=4 end=16 stride=2    # 简单实用序列的方法：创建4 个用户组分表是组group1 group2 group3 group4    - group: name=group{{ item }} state=present      with_sequence: count=4
随机选择with_random_choice
随机选择列表中得一个值
- debug: msg={{ item }}  with_random_choice:     - "go through the door"     - "drink from the goblet"     - "press the red button"     - "do nothing"
合并列表
# 安装所有列表中的软件- name: flattened loop demo  yum: name={{ item }} state=installed  with_flattened:     - [ 'foo-package', 'bar-package' ]     - [ ['one-package', 'two-package' ]]     - [ ['red-package'], ['blue-package']]
注册变量使用循环
- shell: echo "{{ item }}"  with_items:    - one    - two  register: echo- name: Fail if return code is not 0  fail:    msg: "The command ({{ item.cmd }}) did not have a 0 return code"  when: item.rc != 0  with_items: "{{ echo.results }}"
循环主机清单
# 输出所有主机清单里的主机- debug: msg={{ item }}  with_items: "{{ groups['all'] }}"# 输出所有执行的主机- debug: msg={{ item }}  with_items: play_hosts#输出所有主机清单里的主机- debug: msg={{ item }}  with_inventory_hostnames: all# 输出主机清单中不在www中的所有主机- debug: msg={{ item }}  with_inventory_hostnames: all:!www
改变循环的变量项
# main.yml- include: inner.yml  with_items:    - 1    - 2    - 3  loop_control:    loop_var: outer_item# inner.yml- debug: msg="outer item={{ outer_item }} inner item={{ item }}"  with_items:    - a    - b    - c
更多文章请看 Ansible 专题文章总览


作者：lework
链接：http://www.jianshu.com/p/04516cbba336
來源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。