Ansible8:Playbook循环
在使用ansible做自动化运维的时候,免不了的要重复执行某些操作,如:添加几个用户,创建几个MySQL用户并为之赋予权限,操作某个目录下所有文件等等。好在playbook支持循环语句,可以使得某些需求很容易而且很规范的实现。
1、with_items
with_items是playbooks中最基本也是最常用的循环语句:
tasks: - name:Secure config files file: path=/etc/` item ` mode=0600 owner=root group=root with_items: - my.cnf - shadow - fstab
上面例子表示,创建三个文件分别为my.cnf、shadow、fstab
也可以将文件列表提前赋值给一个变量,然后在循环语句中调用:
with_items: "{{ somelist }}"
使用with_items迭代循环的变量可以是个单纯的列表,也可以是一个较为复杂 的数据结果,如字典类型:
tasks: - name: add several users user: name=` item`.`name ` state=present groups=` item`.`groups ` with_items: - { name: 'testuser1', groups: 'wheel' } - { name: 'testuser2', groups: 'root' }
2、with_nested嵌套循环
示例:
tasks: - 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' ]
item[0]是循环的第一个列表的值['alice','bob']。item[1]是第二个列表的值。表示循环创建alice和bob两个用户,并且为其赋予在三个数据库上的所有权限。
也可以将用户列表事先赋值给一个变量:
tasks: - name: here, 'users' contains the above list of employees mysql_user: name={{ item[0] }} priv={{ item[1] }}.*:ALL append_privs=yes password=foo with_nested: - "`users`" - [ 'clientdb', 'employeedb', 'providerdb' ]
3、with_dict
with_dict可以遍历更复杂的数据结构:
假如有如下变量内容:
users: alice: name: Alice Appleworth telephone: 123-456-7890 bob: name: Bob Bananarama telephone: 987-654-3210
现在需要输出每个用户的用户名和手机号:
tasks: - name: Print phone records debug: msg="User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})" with_dict: "{{ users }}"
4、with_fileglob文件匹配遍历
可以指定一个目录,使用with_fileglob可以循环这个目录中的所有文件,示例如下: tasks: - name:Make key directory file: path=/root/.sshkeys ensure=directory mode=0700 owner=root group=root - name:Upload public keys copy: src=` item ` dest=/root/.sshkeys mode=0600 owner=root group=root with_fileglob: - keys/*.pub - name:Assemble keys into authorized_keys file assemble: src=/root/.sshkeys dest=/root/.ssh/authorized_keysmode=0600 owner=root group=root
5、with_subelement遍历子元素
假如现在需要遍历一个用户列表,并创建每个用户,而且还需要为每个用户配置以特定的SSH key登录。变量文件内容如下:
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"
playbook中定义如下:
- 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
也可以遍历嵌套的子列表:
- 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
6、with_sequence循环整数序列
with_sequence可以生成一个自增的整数序列,可以指定起始值和结束值,也可以指定增长步长。 参数以key=value的形式指定,format指定输出的格式。数字可以是十进制、十六进制、八进制:
- hosts: all tasks: # create groups - group: name=evens state=present - group: name=odds state=present # create some test users - user: name=` item ` state=present groups=evens with_sequence: start=0 end=32 format=testuser%02d # create a series of directories with even numbers for some reason - file: dest=/var/stuff/` item ` state=directory with_sequence: start=4 end=16 stride=2 # stride用于指定步长 # a simpler way to use the sequence plugin # create 4 groups - group: name=group` item ` state=present with_sequence: count=4
7、with_random_choice随机选择
从列表中随机取一个值:
- debug: msg=` item ` with_random_choice: - "go through the door" - "drink from the goblet" - "press the red button" - "do nothing"
8、do-Util循环
示例:
- action: shell /usr/bin/foo register: result until: result.stdout.find("all systems go") != -1 retries: 5 delay: 10
重复执行shell模块,当shell模块执行的命令输出内容包含"all systems go"的时候停止。重试5次,延迟时间10秒。retries默认值为3,delay默认值为5。任务的返回值为最后一次循环的返回结果。
9、循环注册变量
在循环中使用register时,保存的结果中包含results关键字,该关键字保存模块执行结果的列表
- shell: echo "` item `" with_items: - one - two register: echo
变量echo内容如下:
{ "changed": true, "msg": "All items completed", "results": [ { "changed": true, "cmd": "echo \"one\" ", "delta": "0:00:00.003110", "end": "2013-12-19 12:00:05.187153", "invocation": { "module_args": "echo \"one\"", "module_name": "shell" }, "item": "one", "rc": 0, "start": "2013-12-19 12:00:05.184043", "stderr": "", "stdout": "one" }, { "changed": true, "cmd": "echo \"two\" ", "delta": "0:00:00.002920", "end": "2013-12-19 12:00:05.245502", "invocation": { "module_args": "echo \"two\"", "module_name": "shell" }, "item": "two", "rc": 0, "start": "2013-12-19 12:00:05.242582", "stderr": "", "stdout": "two" } ] }
遍历注册变量的结果:
- 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`"
10、with_together遍历数据并行集合
示例:
- hosts: webservers remote_user: root vars: alpha: [ 'a','b','c','d'] numbers: [ 1,2,3,4 ] tasks: - debug: msg="` item`.`0 ` and ` item`.`1 `" with_together: - "` alpha `" - "` numbers `"
输出的结果为:
ok: [192.168.1.65] => (item=['a', 1]) => { "item": [ "a", 1 ], "msg": "a and 1" } ok: [192.168.1.65] => (item=['b', 2]) => { "item": [ "b", 2 ], "msg": "b and 2" } ok: [192.168.1.65] => (item=['c', 3]) => { "item": [ "c", 3 ], "msg": "c and 3" } ok: [192.168.1.65] => (item=['d', 4]) => { "item": [ "d", 4 ], "msg": "d and 4" }
loop模块一般在下面的场景中使用
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类似的配置模块重复了多遍
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fact是一个列表
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创建多个文件,然后使用assemble聚合成一个大文件
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使用with_fileglob匹配特定的文件管理
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