ansible 流程控制
playbook 条件语句
不管是 shell 还是各大编程预言中，流程控制，条件判断都是必不可少的，在我们使用 Ansible 的过程中，条件判断的使用频率都非常高。
例如：
1. 我们使用不同的系统的时候，可以通过判断系统 来对软件包进行安装。
2. 在nfs和rsync安装过程中，客户端服务器不需要推送配置文件，之前我们都是写多个play，会影响效率。
3. 我们在源码安装nginx 的时候，执行第二遍就无法执行了，此时我们就可以进行判断是否安装过。
根据不同的操作系统安装apache
官方示例：
tasks:
- name: "shut down Debian flavored systems"
command: /sbin/shutdown -t now
when: ansible_facts['os_family'] == "Debian"
# note that all variables can be used directly in conditionals without double curly braces
示例： 根据不同的 系统安装不同的服务
- hosts: web_group
tasks:
- name: Install CentOS Htt
state: present
#官方
when: ansible_facts['os_family'] == "CentOS"
#非官方
when: ansible_distribution == "CentOS"
- name: Install Ubuntu Httpd
yum:
name: apache2
state: present
when: ansible_facts['os_family'] == "Ubuntu"
可以使用括号对条件进行分组
tasks:
- name: "shut down CentOS 6 and Debian 7 systems"
command: /sbin/shutdown -t now
when: (ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "6") or
(ansible_facts['distribution'] == "Debian" and ansible_facts['distribution_major_version'] == "7")
可以指定多条件为列表
tasks:
- name: "shut down CentOS 6 systems"
command: /sbin/shutdown -t now
when:
- ansible_facts['distribution'] == "CentOS"
- ansible_facts['distribution_major_version'] == "6"
条件运算
tasks:
- shell: echo "only on Red Hat 6, derivatives, and later"
when: ansible_facts['os_family'] == "RedHat" and ansible_facts['lsb']['major_release']|int >= 6
rsync服务端推送配置文件
[root@m01 ~]# cat rsyncd/rsyncd.yml
- hosts: rsync_server
tasks:
- name: Install Rsyncd Server
yum:
name: rsync
state: present
- name: Create www Group
group:
name: www
gid: 666
- name: Create www User
user:
name: www
group: www
uid: 666
create_home: false
shell: /sbin/nologin
- name: Scp Rsync Config
copy:
src: ./rsyncd.j2
dest: /etc/rsyncd.conf
owner: root
group: root
mode: 0644
when: ansible_hostname == "backup"
- name: Create Passwd File
copy:
content: 'rsync_backup:123'
dest: /etc/rsync.passwd
owner: root
group: root
mode: 0600
when: ansible_hostname == "backup"
- name: Create backup Directory
file:
path: /backup
state: directory
mode: 0755
owner: www
name: rsyncd
state: started
when: ansible_hostname == "backup"
rsync客户端推送脚本
[root@m01 ~]# vim rsync.yml
- hosts: rsync_server
tasks:
- name: SCP Backup Shell
copy:
src: ./backup.sh
dest: /root/backup.sh
when: ansible_hostname is match "web*"
#执行结果
PLAY [rsync_server] **************************************************************************************************************************************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************************************************************************************************************************************
ok: [web02]
ok: [backup]
ok: [web01]
TASK [SCP Backup Shell] **********************************************************************************************************************************************************************************************************************
skipping: [backup]
changed: [web01]
changed: [web02]
PLAY RECAP ***********************************************************************************************************************************************************************************************************************************
backup : ok=1 changed=0 unreachable=0 failed=0 skipped=1 rescued=0 ignored=0
web01 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
web02 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
通过register将命令执行结果保存至变量，然后通过when 语句进行判断
- hosts: web_group
tasks:
- name: Check Httpd Server
command: systemctl is-active httpd
ignore_errors: yes
register: check_httpd
- name: debug outprint
debug: var=check_httpd
- name: Httpd Restart
service:
name: httpd
state: restarted
when: check_httpd.rc == 0
使用when判断主机名
- hosts: rsync_server
tasks:
- name: Install rsyncd Server
yum:
name: rsync
state: present
- name: Config rsyncd Conf
copy:
src: ./rsyncd.j2
dest: /etc/rsyncd.conf
owner: root
group: root
mode: 0644
when: ansible_fqdn == 'backup'
- name: Create dir
file:
path: /backup
state: directory
owner: www
group: www
mode: 0755
recurse: yes
when: ansible_fqdn == 'backup'
- name: Create passwd file
copy:
content: "rsync_backup:123"
dest: /etc/rsync.passwd
owner: root
group: root
mode: 0600
when: ansible_fqdn == 'backup'
#单条件判断
- name: Start rsyncd
systemd:
name: rsyncd
state: started
enabled: yes
when: ansible_fqdn == 'backup'
#多条件判断，使用小括号分组
- name: copy shell
template:
src: ./backup.sh
dest: /root
when: (ansible_fqdn == 'web01') or (ansible_fqdn == 'web02')
#多条件判断，使用list列表形式
- name: copy shell
template:
src: ./backup.sh
dest: /root
when:
- ansible_fqdn == 'web01'
- ansible_fqdn == 'web02'
#多条件判断，使用is match 支持通配符
- name: Add Crontab
cron:
name: "backup"
minute: "00"
hour: "01"
job: "/bin/sh /root/backup.sh &>/dev/null"
when: ansible_fqdn is match 'web*'
2.使用when判断系统
- hosts: webs
tasks:
- name: Install CentOS Apache
yum:
name: httpd
state: present
when: ansible_distribution == 'CentOS'
- name: Install Ubuntu Apache
apt:
name: apache2
state: present
when: ansible_distribution == 'Ubuntu'
3.使用when判断系统版本
- hosts: webs
tasks:
- name: Start CentOS6 Httpd
shell: "/etc/init.d/httpd start"
when: ansible_distribution_major_version == '6'
- name: Start CentOS7 Httpd
shell: "systemctl start httpd"
when: ansible_distribution_major_version == '7'
4.使用注册变量对返回值进行判断
- name: pan duan rpm bao
shell: "rpm -qa|grep php"
register: check_php
- name: Install php
shell: "cd /usr/local/src && rpm -Uvh *rpm"
when: check_php.rc != 0
playbook 循环语句
创建目录之类的操作，2个目录就要写两个file 模块来创建，如果有循环，可以减少重复性代码。
1.启动多个服务
- hosts: web_group
tasks:
- name: start service
systemd:
name: "{{ item }}"
state: started
with_items:
- httpd
- php-fpm
- mariadb
2.定义变量循环
- name: ensure a list of packages installed
yum:
name: "{{ packages }}"
vars:
packages:
- httpd
- httpd-tools
- hosts: web_group
tasks:
- name: ensure a list of packages installed
yum: name= "{{ item }}" state=present
with_items:
- httpd
- httpd-tools
3.字典循环
拷贝文件
- hosts: web_group
tasks:
- name: copy conf and code
copy:
src: "{{ item.src }}"
dest: "{{ item.dest }}"
mode: "{{ item.mode }}"
with_items:
- { src: "./httpd.conf", dest: "/etc/httpd/conf/", mode: "0644" }
- { src: "./upload_file.php", dest: "/var/www/html/", mode: "0600" }
- name: tar php and nginx and wordpress
unarchive:
src: "{{ item.src }}"
dest: "{{ item.dest }}"
owner: "{{ item.user }}"
group: "{{ item.user }}"
copy: yes
with_items:
- { src: "./php.tgz", dest: "/usr/local/src", user: "root" }
- { src: "./nginx-1.16.0.tar.gz", dest: "/root", user: "root" }
- { src: "./wordpress.tgz", dest: "/code", user: "www" }
ansible handlers(触发器）
handler 用来执行某些条件下的任务，比如当配置文件发生变化的时候，通过notify 触发 handler去重启服务。
在saltstack中也有类似的触发器，写法相对Ansible简单，只需要watch，配置文件即可。
实践案例：
- name: scp nginx shell conf
copy:
src: "{{ item.src }}"
dest: "{{ item.dest }}"
with_items:
- { src: "./nginx.service", dest: "/usr/lib/systemd/system" }
- { src: "./nginx.conf", dest: "/usr/local/nginx/conf/" }
- { src: "./www.drz.com.conf", dest: "/usr/local/nginx/conf/conf.d" }
#添加触发器
notify: reload nginx
handlers:
- name: reload nginx
systemd:
name: nginx
state: reloaded
注意：
1.无论多少个task通知了相同的handlers，handlers仅会在所有tasks结束后运行一次。
2.Handlers只有在其所在的任务被执行时，才会被运行；如果一个任务中定义了notify调用Handlers，但是由于条件判断等原因，该任务未被执行，那么Handlers同样不会被执行。
3.Handlers只会在每一个play的末尾运行一次；如果想在一个playbook中间运行Handlers，则需要使用meta模块来实现。例如： -meta: flush_handlers。
4.如果一个play在运行到调用Handlers的语句之前失败了，那么这个Handlers将不会被执行。我们可以使用meta模块的--force-handlers选项来强制执行Handlers，即使Handlers所在的play中途运行失败也能执行。
5.不能使用handlers替代tasks
playbook任务标签
默认情 况下，Ansible 在执行一个playbook 时，会执行playbook中定义的所有任务，Ansible的标签 （tag）功能可以给单独任务甚至整个playbook 打上标签，然后利用这些标签来指定要运行playbook中的个别任务，或不执行制定的任务。
打标签的方式
- 对一个task打一个标签
- 对一个task打多个标签
- 对多个task打一个标签
打完标签如何使用
-t : 指定的tag标签任务
--skip-tags : 执行--skip-tags之外的标签任务
使用 - t 指定 tag
[root@m01 m01]# cat tag.yml
- hosts: web_group
vars:
- http_port: 8080
tasks:
- name: Install Http Server
yum:
name: httpd
state: present
tags:
- install_httpd
- httpd_server
- name: configure httpd server
template:
src: ./httpd.j2
dest: /etc/httpd/conf/httpd.conf
notify: Restart Httpd Server
tags:
- config_httpd
- httpd_server
- name: start httpd server
service:
name: httpd
state: started
enabled: yes
tags: service_httpd
handlers:
- name: Restart Httpd Server
systemd:
name: httpd
state: restarted
[root@m01 m01]# ansible-playbook tag.yml --list-tags
[root@m01 m01]# ansible-playbook tag.yml -t httpd_server
[root@m01 m01]# ansible-playbook tag.yml -t install_httpd,confiure_httpd
[root@m01 m01]# ansible-playbook tag.yml --skip-tags httpd_server
playbo ok复用include
在之前写playbook的过程中，写多个playbook没有办法一键执行，所以playbook 中有一个功能，叫做 include 用来动态调用task任务列表。
只调用task include_tasks
调用整个task 文件： include （新版本： import_playbook）
在saltstack中，叫做 top file入口文件。
示例：
[root@m01 web]# vim install_nginx.yml
- name: Install nginx
yum:
name: nginx
state: present
[root@m01 web]# vim conf_nginx.yml
- name: conf nginx
copy:
src: ./www.drz.com.conf
dest: /etc/nginx/conf.d
notify: reload nginx
[root@m01 web]# vim main.yml
- hosts:
tasks:
- include_tasks: ./install_nginx.yml
- include_tasks: ./conf_nginx.yml
handlers:
- name: reload nginx
systemd:
name: nginx
state: reloaded
2.直接复用写好的yml文件
- 旧版：
include - 新版：
import_playbook
- import_playbook: ./lnmp.yml
- import_playbook: ../mariadb/mysql.yml
playbook 忽略错误
默认playbook会监测task 执行的返回状态，如果遇到错误则会立即中止playbook 的后续task执行，然而有些时候playbook 即使执行错误了也要让其继续执行。
加入参数： ignore_errors:yes 忽略错误
[root@m01 ~]# cat ignore.yml
---
- hosts: web_group
tasks:
- name: Ignore False
command: /bin/false
ignore_errors: yes
- name: touch new file
file:
path: /tmp/zls.txt
state: touch
playbook 错误处理
如上所述，当 task 执行失败时，playbook 将不再继续执行，包括如果在task中设置了handler 也不会被执行。
但是我们可以采取强制措施..
强制调用handler
[root@m01 ~]# cat handler.yml
- hosts: web_group
vars:
- http_port: 8080
force_handlers: yes
tasks:
- name: config httpd server
template:
src: ./httpd.j2
dest: /etc/httpd/conf
notify:
- Restart Httpd Server
- Restart PHP Server
- name: Install Http Server
yum:
name: htttpd
state: present
- name: start httpd server
service:
name:httpd
state: started
enabled: yes
handlers:
- name: Restart Httpd Server
systemd:
name: httpd
state: restarted
- name: Restart PHP Server
systemd:
name: php-fpm
state: restarted
抑制changed
被管理主机没有发生变化，可以使用参数将change状态改为ok
[root@m01 ~]# cat handler.yml
- hosts: web_group
vars:
- http_port: 8080
force_handlers: yes
tasks:
- name: shell
shell: netstat -lntup|grep httpd
register: check_httpd
changed_when: false
- name: debug
debug: msg={{ check_httpd.stdout.lines }}
[root@m01 project2]# cat changed_when.yml
- hosts: webservers
vars:
- http_port: 8080
tasks:
- name: configure httpd server
template:
src: ./httpd.j2
dest: /etc/httpd/conf/httpd.conf
notify: Restart Httpd Server
- name: Check HTTPD
shell: /usr/sbin/httpd -t
register: httpd_check
changed_when:
- httpd_check.stdout.find('OK')
- false
- name: start httpd server
service:
name: httpd
state: started
enabled: yes
handlers:
- name: Restart Httpd Server
systemd:
name: httpd
state: restarted
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