Ansible-Playbook-template算数运算以及流程控制

template中使用流程控制 for 和 if

template中也可以使用流程控制 for 循环和 if 条件判断，实现动态生成文件功能

范例

#temlnginx2.yml
---
- hosts: websrvs
  remote_user: root
  vars:
    nginx_vhosts:
      - 81
      - 82
      - 83
  tasks:
    - name: template config
      template: src=nginx.conf.j2 dest=/data/nginx.conf

#templates/nginx.conf2.j2
{% for vhost in  nginx_vhosts %}
server {
   listen {{ vhost }}
}
{% endfor %}

ansible-playbook -C  templnginx2.yml  --limit 10.0.0.8

#生成的结果：
server {
   listen 81   
}
server {
   listen 82   
}
server {
   listen 83   
}

范例：

#temlnginx3.yml
---
- hosts: websrvs
  remote_user: root
  vars:
    nginx_vhosts:
      - listen: 8080
  tasks:
    - name: config file
      template: src=nginx.conf3.j2 dest=/data/nginx3.conf

#templates/nginx.conf3.j2
{% for vhost in nginx_vhosts %}   
server {
  listen {{ vhost.listen }}
}
{% endfor %}

ansible-playbook   templnginx3.yml  --limit 10.0.0.8

#生成的结果
server {
  listen 8080  
}

范例：

#templnginx4.yml
- hosts: websrvs
  remote_user: root
  vars:
    nginx_vhosts:
      - listen: 8080
        server_name: "web1.magedu.com"
        root: "/var/www/nginx/web1/"
      - listen: 8081
        server_name: "web2.magedu.com"
        root: "/var/www/nginx/web2/"
      - {listen: 8082, server_name: "web3.magedu.com", root: "/var/www/nginx/web3/"}
  tasks:
    - name: template config 
      template: src=nginx.conf4.j2 dest=/data/nginx4.conf

# templates/nginx.conf4.j2
{% for vhost in nginx_vhosts %}
server {
   listen {{ vhost.listen }}
   server_name {{ vhost.server_name }}
   root {{ vhost.root }}  
}
{% endfor %}

ansible-playbook  templnginx4.yml --limit 10.0.0.8

#生成结果：
server {
    listen 8080
    server_name web1.magedu.com
    root /var/www/nginx/web1/  
}
server {
    listen 8081
    server_name web2.magedu.com
    root /var/www/nginx/web2/  
}
server {
    listen 8082
    server_name web3.magedu.com
    root /var/www/nginx/web3/  
} 

在模版文件中还可以使用 if条件判断，决定是否生成相关的配置信息

范例：

#templnginx5.yml
- hosts: websrvs
  remote_user: root
  vars:
    nginx_vhosts:
      - web1:
        listen: 8080
        root: "/var/www/nginx/web1/"
      - web2:
        listen: 8080
        server_name: "web2.magedu.com"
        root: "/var/www/nginx/web2/"
      - web3:
        listen: 8080
        server_name: "web3.magedu.com"
        root: "/var/www/nginx/web3/"
  tasks:
    - name: template config to 
      template: src=nginx.conf5.j2 dest=/data/nginx5.conf

#templates/nginx.conf5.j2
{% for vhost in  nginx_vhosts %}
server {
   listen {{ vhost.listen }}
   {% if vhost.server_name is defined %}
server_name {{ vhost.server_name }}
   {% endif %}
root  {{ vhost.root }}
}
{% endfor %}

#生成的结果
server {
   listen 8080
   root  /var/www/nginx/web1/
}
server {
   listen 8080
   server_name web2.magedu.com
   root  /var/www/nginx/web2/
}
server {
   listen 8080
   server_name web3.magedu.com
   root  /var/www/nginx/web3/
}

playbook使用 when

when语句，可以实现条件测试。如果需要根据变量、facts或此前任务的执行结果来做为某task执行与否的前提时要用到条件测试,通过在task后添加when子句即可使用条件测试，jinja2的语法格式

范例：

---
- hosts: websrvs
  remote_user: root
  tasks:
    - name: "shutdown RedHat flavored systems"
      command: /sbin/shutdown -h now
      when: ansible_os_family == "RedHat"

范例：

---
- hosts: websrvs
  remote_user: root
  tasks:
    - name: add group nginx
      tags: user
      user: name=nginx state=present
    - name: add user nginx
      user: name=nginx state=present group=nginx
    - name: Install Nginx
      yum: name=nginx state=present
    - name: restart Nginx
      service: name=nginx state=restarted
      when: ansible_distribution_major_version == “6”

范例：

---
- hosts: websrvs
  remote_user: root
  tasks: 
    - name: install conf file to centos7
      template: src=nginx.conf.c7.j2 dest=/etc/nginx/nginx.conf
      when: ansible_distribution_major_version == "7"
    - name: install conf file to centos6
      template: src=nginx.conf.c6.j2 dest=/etc/nginx/nginx.conf
      when: ansible_distribution_major_version == "6"

playbook 使用迭代 with_items

迭代：当有需要重复性执行的任务时，可以使用迭代机制
对迭代项的引用，固定变量名为”item“
要在task中使用with_items给定要迭代的元素列表

列表元素格式：

• 字符串
• 字典

范例：

---
- hosts: websrvs
  remote_user: root

  tasks:
    - name: add several users
      user: name={{ item }} state=present groups=wheel
      with_items:
        - testuser1
        - testuser2
#上面语句的功能等同于下面的语句
    - name: add user testuser1
      user: name=testuser1 state=present groups=wheel
    - name: add user testuser2
      user: name=testuser2 state=present groups=wheel

范例：

---
#remove mariadb server
- hosts: appsrvs:!192.168.38.8
  remote_user: root

  tasks:
    - name: stop service
      shell: /etc/init.d/mysqld stop
    - name:  delete files and dir
      file: path={{item}} state=absent
      with_items:
        - /usr/local/mysql
        - /usr/local/mariadb-10.2.27-linux-x86_64
        - /etc/init.d/mysqld
        - /etc/profile.d/mysql.sh
        - /etc/my.cnf
        - /data/mysql
    - name: delete user
      user: name=mysql state=absent remove=yes 

范例：

---
- hosts：websrvs
  remote_user: root

  tasks
    - name: install some packages
      yum: name={{ item }} state=present
      with_items:
        - nginx
        - memcached
        - php-fpm 

​

范例：

---
- hosts: websrvs
  remote_user: root
  tasks:
    - name: copy file
      copy: src={{ item }} dest=/tmp/{{ item }}
      with_items:
        - file1
        - file2
        - file3
    - name: yum install httpd
      yum: name={{ item }}  state=present 
      with_items:
        - apr
        - apr-util
        - httpd

​

迭代嵌套子变量：在迭代中，还可以嵌套子变量，关联多个变量在一起使用

示例：

---
- hosts: websrvs
  remote_user: root

  tasks:
    - name: add some groups
      group: name={{ item }} state=present
      with_items:
        - nginx
        - mysql
        - apache
    - name: add some users
      user: name={{ item.name }} group={{ item.group }} state=present
      with_items:
        - { name: 'nginx', group: 'nginx' }
        - { name: 'mysql', group: 'mysql' }
        - { name: 'apache', group: 'apache' }

范例：

cat with_item2.yml
---
- hosts: websrvs
  remote_user: root

  tasks:
    - name: add some groups
      group: name={{ item }} state=present
      with_items:
        - g1
        - g2
        - g3
    - name: add some users
      user: name={{ item.name }} group={{ item.group }} home={{ item.home }} create_home=yes state=present
      with_items:
        - { name: 'user1', group: 'g1', home: '/data/user1' }
        - { name: 'user2', group: 'g2', home: '/data/user2' }
        - { name: 'user3', group: 'g3', home: '/data/user3' }

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