playbook條件語句

一：判斷語句when
    根據(jù)不同的操作系統(tǒng)進(jìn)行判斷   Apache 
        centOS   httpd 
        Ubuntu   httpd2
    根據(jù)不同的主機(jī)名稱進(jìn)行判斷

[root@manager ansible_tasks]# cat t1.yml

• hosts: webservers
  tasks:
  • name: Installed HTTP Server
    yum:
    name: httpd
    state: present
    when: (ansible_distribution == "CentOS")
    判斷：如果是centos就執(zhí)行httpd恩溅。
  • name: Installed HTTP Server
    yum:
    name: httpd2
    state: present
    when: (ansible_distribution == "Ubuntu")
    判斷：如果是ubuntu就執(zhí)行httpd2.

實(shí)例：如果有100臺(tái)服務(wù)器，只需要其中的10臺(tái)安裝nginx套么，那么我們就可以將這10臺(tái)主機(jī)放在一個(gè)web組富玷，然后只安裝web組里的攀涵。
就需要做判斷：
[root@manager ansible_tasks]# cat t2.yml

• hosts: all
  tasks:
  • name: Installed Nginx Web Server
    yum:
    name: nginx
    state: present
    when: ( ansible_hostname is match("web*"))
    意思：是web的都安裝抖格，不是web的都跳過钝腺。

when: ( ansible_hostname is match("web")) or ( ansible_hostname is match("web"))
意思是：web和lb都安裝龄捡。or是或的意思

二：循環(huán)語句loop|with_item

    一個(gè)tasks安裝多個(gè)軟件  （列表）     

[root@manager ansible_tasks]# cat t3.yml

• hosts: webservers
  tasks:

  • name: Install Rpm All
    yum:
    name: "{{ item }}"
    state: present
    loop:

    • httpd
    • httpd-tools

    一個(gè)tasks啟動(dòng)多個(gè)服務(wù) （列表）
    [root@manager ansible_tasks]# cat t4.yml

• hosts: webservers
  tasks:

  • name: Started Nginx And PHP_FPM Server
    systemd:
    name: "{{ item }}"
    state: started
    enabled: yes
    loop:

    • nginx
    • php-fpm

    一個(gè)tasks拷貝多個(gè)文件 （字典）
    [root@manager ansible_tasks]# cat t5.yml

• hosts: webservers
  tasks:
  • name: Configure Rsync Deamon
    copy:
    src: "{{ item.src }}"
    dest: "{{ item.dest }}"
    mode: "{{ item.mode }}"
    loop:
    • { src: rsyncd.conf.j2, dest: /opt/rsyncd.conf, mode: "0644" }
    • { src: rsync.pass.j2, dest: /opt/rsync.pass, mode: "0600" }

批量創(chuàng)建用戶啦辐，使用key values字典的方式
testuser1   基本組 bin         8989    /bin/bash
testuser2   基本組 root        7878    /bin/sh

[root@manager ansible_tasks]# cat t6.yml

• hosts: webservers
  tasks:
  • name: Create Users
    user:
    name: "{{ item.name }}"
    uid: "{{ item.uid }}"
    group: "{{ item.group }}"
    shell: "{{ item.shell }}"
    loop:
    • { name: testuser1 , uid: 8989 , group: bin , shell: /bin/bash }
    • { name: testuser2 , uid: 7878 , group: root , shell: /bin/sh }

三：觸發(fā)器 Handlers

四：標(biāo)簽 Tag
[root@manager ansible_tasks]# cat t7.yml

• hosts: webservers
  tasks:

  • name: Install Nfs Server
    yum:
    name: nfs-utils
    state: present
    tags: install_nfs
  • name: Service Nfs Server
    service:
    name: nfs-server
    state: started
    enabled: yes
    tags: start_nfs

  指定執(zhí)行 playbook中的某一個(gè)標(biāo)簽 （ 通常是用來快速解決問題 ）
  [root@manager ansible_tasks]# ansible-playbook t7.yml -t install_nfs
  指定排除某個(gè)tags谓传，其余都正常執(zhí)行
  [root@manager ansible_tasks]# ansible-playbook t7.yml --skip-tags install_nfs

五：包含 Include | include_tasks

[root@manager ansible_tasks]# cat restart_nginx.yml

• name: Restart Nginx Server
  systemd:
  name: nginx
  state: restarted
  [root@manager ansible_tasks]# cat a_project.yml
• hosts: webservers
  tasks:

  • name: A Project command
    command: echo "A"

  • name: Restart Nginx
    include: restart_nginx.yml
    [root@manager ansible_tasks]# cat b_project.yml

• hosts: webservers
  tasks:

  • name: B Project command
    command: echo "B"

  • name: Restart Nginx
    include: restart_nginx.yml

六：忽略錯(cuò)誤 Ignore_errors

[root@manager ansible_tasks]# cat errors.yml

• hosts: webservers
  tasks:
  • name: Shell Command
    command: /bin/false
    ignore_errors: yes #忽略錯(cuò)誤
  • name: Create File
    file:
    path: /tmp/oldux_tt
    state: touch

gnore_errors使用：當(dāng)我們發(fā)現(xiàn) 某個(gè)task 偶爾會(huì)執(zhí)行失敗，但該task并不影響后續(xù)的tasks正常運(yùn)行芹关，那么此時(shí)可以 添加一個(gè)ignore_errors忽略經(jīng)常出錯(cuò)的這個(gè)task

七： 異常處理

1.控制task報(bào)告的狀態(tài)续挟，不一定必須是"changed"
[root@manager ansible_tasks]# cat t8.yml

• hosts: webservers
  tasks:
  • name: Get Nginx Port Status
    shell: netstat -lntp | grep nginx
    register: ngx_status
    changed_when: false #（該tasks任務(wù)不會(huì)發(fā)生changed提示了）
  • name: Debug Nginx Status
    debug:
    msg: "{{ ngx_status.stdout_lines }}"

2.使用changed_when檢查tasks任務(wù)返回的結(jié)果
[root@manager ansible_tasks]# cat t9.yml

• hosts: webservers
  tasks:

  • name: Install Nginx Server
    yum:
    name: nginx
    state: present
    tags: Install_Nginx_Server

  • name: Configure Nginx Server
    copy:
    src: ./nginx.conf.j2
    dest: /etc/nginx/nginx.conf
    notify: Restart Nginx Server

  • name: Check Nginx Configure File
    shell: nginx -t
    register: check_ngx #將nginx -t的結(jié)果存儲(chǔ)至check_ngx變量中
    changed_when:

    • false #由于沒有在被控端執(zhí)行任何操作，所以可以將其修改為false侥衬，這個(gè)任務(wù)每次執(zhí)行就ok狀態(tài)
    • check_ngx.stdout.find('successful') #檢查變量中是否存在successful的字符串诗祸，如果存在則繼續(xù)，不存在則停止轴总，并報(bào)錯(cuò)直颅。

  • name: Started Nginx Server
    systemd:
    name: nginx
    state: started
    enabled: yes

  handlers:

  • name: Restart Nginx Server
    systemd:
    name: nginx
    state: restarted
    配置文件一旦拷貝錯(cuò)誤，在重啟的時(shí)候就會(huì)報(bào)錯(cuò)怀樟，服務(wù)掛掉功偿，
    所以這個(gè)判斷做語法判斷是非常有限，又可以檢測(cè)往堡，又可以不影響服務(wù)的使用械荷。
    它會(huì)在出現(xiàn)語法錯(cuò)誤之后就停止執(zhí)行。也就不會(huì)在去加載啟動(dòng)模塊投蝉。