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自动化运维工具Ansible（5）流程控制
2022-08-04 05:27:00 【AHui_CSDN】
playbook条件语句
不管是shell还是各大编程语言中，流程控制，条件判断这些都是必不可少的，在我们使用Ansible的过程中，条件判断的使用频率极其高。
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
- hosts: web_group
tasks:
- name: Install CentOS Httpd
yum:
name: httpd
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"
还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")
也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
过滤匹配返回值包含successful
- name: Check Nginx Configure
command: /usr/sbin/nginx -t
register: result
- name: Restart web02
command: /usr/sbin/reboot
when: result.stderr_lines is match "successful"
或者
when: result.stderr_lines is search "successful"
rsync服务端推送配置文件
[[email protected] ~]# 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
group: www
recurse: yes
when: ansible_hostname == "backup"
- name: Start Rsyncd Server
systemd:
name: rsyncd
state: started
when: ansible_hostname == "backup"
rsync客户端推送脚本
[[email protected] ~]# 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
playbook循环语句
在之前的学习过程中，我们经常会有传送文件，创建目录之类的操作，创建2个目录就要写两个file模块来创建，如果要创建100个目录，我们需要写100个file模块？？？妈耶~~~~ 当然不是，只要有循环即可，减少重复性代码。
启动多个服务
- hosts: web_group
tasks:
- name: start service
systemd:
name: "{
{ item }}"
state: started
with_items:
- httpd
- php-fpm
- mariadb
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
字典循环
1.创建用户
[[email protected] ~]# cat loop.yml
- hosts: web_group
tasks:
- name: Add Users
user:
name: "{
{ item.name }}"
groups: "{
{ item.groups }}"
state: present
with_items:
- {
name: 'ahui', groups: 'linux' }
- {
name: 'go', groups: 'python' }
2.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" }
playbook handlers
什么是handlers?
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
[[email protected] ~]# cat handler.yml
- hosts: web_group
vars:
- http_port: 8080
tasks:
- name: Install Http Server
yum:
name: httpd
state: present
- name: config httpd server
template:
src: ./httpd.j2
dest: /etc/httpd/conf
notify:
- Restart Httpd Server
- Restart PHP Server
- 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
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，或不执行指定的任务。
打标签的方式
1.对一个task打一个标签
2.对一个task打多个标签
3.对多个task打一个标签
打完标签如何使用
-t:执行指定的tag标签任务
–skip-tags:执行–skip-tags之外的标签任务
使用-t指定tag
[[email protected] 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
[[email protected] m01]# ansible-playbook tag.yml --list-tags
[[email protected] m01]# ansible-playbook tag.yml -t httpd_server
[[email protected] m01]# ansible-playbook tag.yml -t install_httpd,confiure_httpd
[[email protected] m01]# ansible-playbook tag.yml --skip-tags httpd_server
playbook文件复用
在之前写playbook的过程中，我们发现，写多个playbook没有办法，一键执行，这样我们还要单个playbook挨个去执行，很鸡肋。所以在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。
示例一：
[[email protected] m01]# cat task.yml
- hosts: web_group
vars:
- http_port: 8080
tasks:
- include_tasks: task_install.yml
- include_tasks: task_configure.yml
- include_tasks: task_start.yml
handlers:
- name: Restart Httpd Server
systemd:
name: httpd
state: restarted
[[email protected] m01]# cat task_install.yml
- name: Install Http Server
yum:
name: httpd
state: present
[[email protected] m01]# cat task_configure.yml
- name: configure httpd server
template:
src: ./httpd.j2
dest: /etc/httpd/conf/httpd.conf
notify: Restart Httpd Server
[[email protected] m01]# cat task_start.yml
- name: start httpd server
service:
name: httpd
state: started
enabled: yes
示例二
- include: httpd.yml
- include: nfs.yml
- include: rsync.yml
示例三
- import_playbook: httpd.yml
- import_playbook: nfs.yml
- import_playbook: rsync.yml
playbook忽略错误
默认playbook会检测task执行的返回状态，如果遇到错误则会立即终止playbook的后续task执行，然鹅有些时候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
[[email protected] ~]# cat ignore.yml
- hosts: web_group
tasks:
- name: Ignore False
command: /bin/false
ignore_errors: yes
- name: touch new file
file:
path: /tmp/ahui.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
[[email protected] ~]# 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
[[email protected] ~]# 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 }}
[[email protected] 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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