Ansible从入门到精通【六】

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专栏名称：Ansible从入门到精通立志成为ansible大佬

ansible templates

- 模板（templates）的认识
- - 模板的使用方式
  - 模板的目录
  - 帮助文档
  - 使用模板管理nginx
  - 修改nginx的work数量
  - - [ansible cpu变量查看](#ansible cpu变量查看)
    - 编辑模板文件
    - 修改template剧本
    - 再次执行
    - 查看配置文件是否读取变量
- when的使用

模板（templates）的认识

模板的使用方式

文本文件，嵌套有脚本（使用模板编程语言编写）
jinja2语言，使用字面量，有下面形式
字符串：使用单引号或者双引号
数字：整数，浮点数
列表：[item1,item2,...]
元组；（item1,item2,...）
字典:{key1:value1,key2:value2,...}
布尔：true/false
算数运算：+，-，*，/，//,%,**
比较运算：==，!=,>,>=,<,<=
逻辑运算：and,or,not
流表达式：For If When

模板的目录

一般建议在ansible目录下创建templates目录，与playbook剧本平行

帮助文档

bash 复制代码

[root@zhaoyj ansible]# ansible-doc -s template
- name: Template a file out to a remote server
  template:
      attributes:            # The attributes the resulting file or directory should have. To get supported flags look at the man page for `chattr' on the target
                               system. This string should contain the attributes in the same order as the one displayed by `lsattr'. The
                               `=' operator is assumed as default, otherwise `+' or `-' operators need to be included in the string.
      backup:                # Create a backup file including the timestamp information so you can get the original file back if you somehow clobbered it incorrectly.
      block_end_string:      # The string marking the end of a block.
      block_start_string:    # The string marking the beginning of a block.
      dest:                  # (required) Location to render the template to on the remote machine.
      follow:                # Determine whether symbolic links should be followed. When set to `yes' symbolic links will be followed, if they exist. When set to `no'
                               symbolic links will not be followed. Previous to Ansible 2.4, this was hardcoded as `yes'.
      force:                 # Determine when the file is being transferred if the destination already exists. When set to `yes', replace the remote file when contents
                               are different than the source. When set to `no', the file will only be transferred if the destination does
                               not exist.
      group:                 # Name of the group that should own the file/directory, as would be fed to `chown'.
      lstrip_blocks:         # Determine when leading spaces and tabs should be stripped. When set to `yes' leading spaces and tabs are stripped from the start of a
                               line to a block. This functionality requires Jinja 2.7 or newer.
      mode:                  # The permissions the resulting file or directory should have. For those used to `/usr/bin/chmod' remember that modes are actually octal
                               numbers. You must either add a leading zero so that Ansible's YAML parser knows it is an octal number
                               (like `0644' or `01777') or quote it (like `'644'' or `'1777'') so Ansible receives a string and can do
                               its own conversion from string into number. Giving Ansible a number without following one of these rules
                               will end up with a decimal number which will have unexpected results. As of Ansible 1.8, the mode may be
                               specified as a symbolic mode (for example, `u+rwx' or `u=rw,g=r,o=r').
      newline_sequence:      # Specify the newline sequence to use for templating files.
      output_encoding:       # Overrides the encoding used to write the template file defined by `dest'. It defaults to `utf-8', but any encoding supported by python
                               can be used. The source template file must always be encoded using `utf-8', for homogeneity.
      owner:                 # Name of the user that should own the file/directory, as would be fed to `chown'.
      selevel:               # The level part of the SELinux file context. This is the MLS/MCS attribute, sometimes known as the `range'. When set to `_default', it
                               will use the `level' portion of the policy if available.
      serole:                # The role part of the SELinux file context. When set to `_default', it will use the `role' portion of the policy if available.

使用模板管理nginx

模拟一个nginx的模板文件

bash 复制代码

cp /etc/nginx/nginx.conf /root/ansible/templates/nginx.conf.j2

编写yml剧本

yaml 复制代码

[root@zhaoyj ansible]# cat templates.yml 
---
- hosts: test
  remote_user: root

  tasks:
    - name: install pkg
      yum: name=nginx
    - name: copy template
      template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf
    - name: start service
      service: name=nginx state=started enabled=yes
...

测试yml

bash 复制代码

[root@zhaoyj ansible]# ansible-playbook -C templates.yml

执行（这里报错了，是因为主控机有证书）

bash 复制代码

[root@zhaoyj ansible]# ansible-playbook  templates.yml 

PLAY [test] ***********************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ************************************************************************************************************************************************************************************************
ok: [192.168.6.249]

TASK [install pkg] ****************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

TASK [copy template] **************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

TASK [start service] **************************************************************************************************************************************************************************************************
fatal: [192.168.6.249]: FAILED! => {"changed": false, "msg": "Unable to start service nginx: Job for nginx.service failed because the control process exited with error code. See \"systemctl status nginx.service\" and \"journalctl -xe\" for details.\n"}

PLAY RECAP ************************************************************************************************************************************************************************************************************
192.168.6.249              : ok=3    changed=2    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

修改nginx的work数量

修改nginx的work数量，根据实际的cpu生成

ansible cpu变量查看

bash 复制代码

[root@zhaoyj ansible]# ansible test -m setup |grep "cpu"
        "ansible_processor_vcpus": 8,

编辑模板文件

bash 复制代码

[root@zhaoyj templates]# vim nginx.conf.j2 


user  nginx;
worker_processes  {{ ansible_processor_vcpus*2 }};

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

修改template剧本

yaml 复制代码

[root@zhaoyj ansible]# cat templates.yml 
---
- hosts: test
  remote_user: root

  tasks:
    - name: install pkg
      yum: name=nginx
    - name: copy template
      template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf
      notify: restart service
    - name: start service
      service: name=nginx state=started enabled=yes
  handlers:
    - name: restart service
      service:  name=nginx state=restarted
...

再次执行

bash 复制代码

[root@zhaoyj ansible]# ansible-playbook templates.yml 

PLAY [test] ***********************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ************************************************************************************************************************************************************************************************
ok: [192.168.6.249]

TASK [install pkg] ****************************************************************************************************************************************************************************************************
ok: [192.168.6.249]

TASK [copy template] **************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

TASK [start service] **************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

RUNNING HANDLER [restart service] *************************************************************************************************************************************************************************************
changed: [192.168.6.249]

PLAY RECAP ************************************************************************************************************************************************************************************************************
192.168.6.249              : ok=5    changed=3    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

查看配置文件是否读取变量

bash 复制代码

192.168.6.249 | CHANGED | rc=0 >>
worker_processes  16;
[root@zhaoyj ansible]# ansible test -m shell -a "ps aux|grep nginx"
192.168.6.249 | CHANGED | rc=0 >>
root     16342  0.0  0.0  49072  1168 ?        Ss   17:16   0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
nginx    16343  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16344  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16345  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16346  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16347  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16348  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16349  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16350  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16351  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16352  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16353  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16354  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16355  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16356  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16357  0.0  0.0  49460  1900 ?        S    17:16   0:00 nginx: worker process
nginx    16358  0.0  0.0  49460  1636 ?        S    17:16   0:00 nginx: worker process
root     17699  0.0  0.0 113284  1204 pts/1    S+   17:20   0:00 /bin/sh -c ps aux|grep nginx
root     17701  0.0  0.0 112816   960 pts/1    S+   17:20   0:00 grep nginx

when的使用

条件测试：

如果需要根据变量，facts或此前任务的执行结果来做为某task执行与否的前提是要用到条件测试，通过when语句实现，在task中使用，jinja2的语法格式
when语句:

在task后添加when子句即可使用条件测试，when语句支持jinja2语法

比如：

查看版本号

powershell 复制代码

[root@zhaoyj ansible]# ansible test -m setup -a "filter="*distribution*""
192.168.6.249 | SUCCESS => {
    "ansible_facts": {
        "ansible_distribution": "CentOS", 
        "ansible_distribution_file_parsed": true, 
        "ansible_distribution_file_path": "/etc/redhat-release", 
        "ansible_distribution_file_variety": "RedHat", 
        "ansible_distribution_major_version": "7", 
        "ansible_distribution_release": "Core", 
        "ansible_distribution_version": "7.9", 
        "discovered_interpreter_python": "/usr/bin/python"
    }, 
    "changed": false
}

记录 "ansible_distribution_major_version": "7", 设置当系统等于7时，复制配置文件

修改模板文件

powershell 复制代码

[root@zhaoyj ansible]# cat templates.yml 
---
- hosts: test
  remote_user: root

  tasks:
    - name: install pkg
      yum: name=nginx
    - name: copy template
      template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf
      when: ansible_distribution_major_version == "7"
      notify: restart service
    - name: start service
      service: name=nginx state=started enabled=yes
  handlers:
    - name: restart service
      service:  name=nginx state=restarted
...

执行剧本

powershell 复制代码

[root@zhaoyj ansible]# ansible-playbook templates.yml 

PLAY [test] ***********************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ************************************************************************************************************************************************************************************************
ok: [192.168.6.249]

TASK [install pkg] ****************************************************************************************************************************************************************************************************
ok: [192.168.6.249]

TASK [copy template] **************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

TASK [start service] **************************************************************************************************************************************************************************************************
changed: [192.168.6.249]

RUNNING HANDLER [restart service] *************************************************************************************************************************************************************************************
changed: [192.168.6.249]

PLAY RECAP ************************************************************************************************************************************************************************************************************
192.168.6.249              : ok=5    changed=3    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

[root@zhaoyj ansible]# ansible test -m shell -a "cat /etc/nginx/nginx.conf|grep centos"
192.168.6.249 | CHANGED | rc=0 >>
#centos 7

嵌套变量传递

我们在制作模板是支持传递变量，可传递单一变量，或者是以列表方式传递，例如：

yaml 复制代码

---
- hosts: test
  remote_user: root

  tasks:
    - name: create some groups
      group: name={{ item }}
      with_items:
        - group1
        - group2
        - group3

    - name: create some user
      user: name={{ item.name }} group={{ item.group }}
      with_items:
        - { name: 'name1', group: 'group1' }
        - { name: 'name2', group: 'group2' }
        - { name: 'name3', group: 'group3' }
...

执行

swift 复制代码

```bash
[root@192-168-6-228 ansible]# ansible-playbook  test.yml 

PLAY [test] ****************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************
ok: [192.168.6.223]

TASK [create some groups] **************************************************************************************************************************************************************
changed: [192.168.6.223] => (item=group1)
changed: [192.168.6.223] => (item=group2)
changed: [192.168.6.223] => (item=group3)

TASK [create some user] ****************************************************************************************************************************************************************
changed: [192.168.6.223] => (item={u'group': u'group1', u'name': u'name1'})
changed: [192.168.6.223] => (item={u'group': u'group2', u'name': u'name2'})
changed: [192.168.6.223] => (item={u'group': u'group3', u'name': u'name3'})

PLAY RECAP *****************************************************************************************************************************************************************************
192.168.6.223              : ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

验证结果

bash 复制代码

[root@192-168-6-228 ansible]# ansible test -m shell -a "getent passwd"|grep name
name1:x:1003:1003::/home/name1:/bin/bash
name2:x:1004:1004::/home/name2:/bin/bash
name3:x:1005:1005::/home/name3:/bin/bash

[root@192-168-6-228 ansible]# ansible test -m shell -a "getent group|grep 100[3-5]"
192.168.6.223 | CHANGED | rc=0 >>
group1:x:1003:
group2:x:1004:
group3:x:1005:

FOR循环与条件判断

FOR循环

格式**(% for vhost in nginx_vhosts %)**

示例：

bash 复制代码

[root@192-168-6-228 ansible]# cat test1.yml 
---
- hosts: test
  remote_user: root
  vars: 
    ports:
      - 81 
      - 82
      - 83

  tasks:
    - name: copy file
      template: src=port.j2 dest=/tmp/port 
...

编写一个模板文件

bash 复制代码

[root@192-168-6-228 ansible]# cat templates/port.j2
{% for port in ports %}
server{
	listen {{ port }}
}
{% endfor %}

注意：for循环里的in ports，这个ports需要和剧本里定义的一样

执行

bash 复制代码

[root@192-168-6-228 ansible]# ansible-playbook test1.yml 

PLAY [test] ****************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************
ok: [192.168.6.223]

TASK [copy file] ***********************************************************************************************************************************************************************
changed: [192.168.6.223]

PLAY RECAP *****************************************************************************************************************************************************************************
192.168.6.223              : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

结果查看

bash 复制代码

[root@192-168-6-228 ansible]# ansible test -m shell -a "cat /tmp/port"
192.168.6.223 | CHANGED | rc=0 >>
server{
	listen 81
}
server{
	listen 82
}
server{
	listen 83
}

也可以改成字典方式去循环，例如：

bash 复制代码

[root@192-168-6-228 ansible]# cat test1.yml 
---
- hosts: test
  remote_user: root
  vars: 
    ports:
      - listen_port: 81 
      - listen_port: 82
      - listen_port: 83

  tasks:
    - name: copy file
      template: src=port.j2 dest=/tmp/port 
...

模板修改

bash 复制代码

[root@192-168-6-228 ansible]# cat templates/port.j2
{% for port in ports %}
server{
	listen {{ port.listen_port }}
}
{% endfor %}

先删除之前的文件在看效果

bash 复制代码

[root@192-168-6-228 ansible]# ansible test -m shell -a "rm -f  /tmp/port"
[WARNING]: Consider using the file module with state=absent rather than running 'rm'.  If you need to use command because file is insufficient you can add 'warn: false' to this
command task or set 'command_warnings=False' in ansible.cfg to get rid of this message.
192.168.6.223 | CHANGED | rc=0 >>

[root@192-168-6-228 ansible]# ansible test -m shell -a "cat   /tmp/port"
192.168.6.223 | FAILED | rc=1 >>
cat: /tmp/port: No such file or directorynon-zero return code

[root@192-168-6-228 ansible]# ansible-playbook test1.yml 

PLAY [test] ****************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************
ok: [192.168.6.223]

TASK [copy file] ***********************************************************************************************************************************************************************
changed: [192.168.6.223]

PLAY RECAP *****************************************************************************************************************************************************************************
192.168.6.223              : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

[root@192-168-6-228 ansible]# ansible test -m shell -a "cat   /tmp/port"
192.168.6.223 | CHANGED | rc=0 >>
server{
	listen 81
}
server{
	listen 82
}
server{
	listen 83
}

与第一种方法是一致的

if判断

模板里也支持if判断。例如修改上面的模板，当listen_port变量为空，就不执行

bash 复制代码

---
- hosts: test
  remote_user: root
  vars: 
    ports:
      - listen_port: 81 
      - listen_port: 82
      - listen_port:

  tasks:
    - name: copy file
      template: src=port.j2 dest=/tmp/port 
...

模板修改

bash 复制代码

[root@192-168-6-228 ansible]# cat templates/port.j2
{% for port in ports %}
server{
{% if port.listen_port is none %}
	listen {{ port.listen_port }}
{% endif %}
}
{% endfor %}

if是none情况下，代表参数定义但是值为空是真
if是defined情况下，代表参数定义了为真
if是undefined情况下，代表参数未定义为真

结果查看

bash 复制代码

[root@192-168-6-228 ansible]# ansible-playbook  test3.yml 

PLAY [test] ****************************************************************************************************************************************************************************

TASK [Gathering Facts] *****************************************************************************************************************************************************************
ok: [192.168.6.223]

TASK [copy file] ***********************************************************************************************************************************************************************
changed: [192.168.6.223]

PLAY RECAP *****************************************************************************************************************************************************************************
192.168.6.223              : ok=2    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

[root@192-168-6-228 ansible]# ansible test -m shell -a "cat   /tmp/port"
192.168.6.223 | CHANGED | rc=0 >>
server{
	listen 
}