ansible中的任务控制
一.循环
循环迭代任务
1.简单循环
loop: ##赋值列表
- value1
- value2
- ...
{
{
item}} ##迭代变量名称
实例
---
- name: create file
hosts: 172.25.11.254
tasks:
- name: file module
file:
name: /mnt/{
{item}}
state: present
loop:
- westos_file1
- westos_file2
2.循环散列或字典列表
---
- name: create file
hosts: 172.25.11.254
tasks:
- name: file module
service:
name: "{
{ item.name}}"
state: "{
{ item.state }}"
loop:
- name: httpd
state: started
- name: vsftpd
state: stopped
例题
受控主机上安装httpd .vsftpd. dhcp-server
并且建立两个用户
westosuser1 组id 444 家目录：/mnt/westosusr1
westosuser2 组id 6666 家目录： /mnt/westosuser2
两个用户的附加组是21
---
- name: dnf and create user
hosts: 172.25.11.3
tasks:
- name: dnf vsftpd http dhcp-server
dnf :
name: "{
{item.name}}"
state: present
loop:
- name: vsftpd
- name: httpd
- name: dhcp-server
- name: create group
group:
name: "{
{item.name}}"
gid: "{
{item.gid}}"
state: present
loop:
- name: westosuser1
gid: 444
- name: westosuser2
gid: 6666
- name: westosuser
gid: 21
ignore_errors: yes ###受控主机中的21组存在，忽略错误继续执行
- name: create user
user:
name: "{
{item.name}}"
group: "{
{item.group}}"
home: "{
{item.home}}"
groups: 21
loop:
- name: westosuser1
group: 444
home: /mnt/westosuser1
- name: westosuser2
group: 6666
home: /mnt/westosuser2
二.条件
when:
- 条件1
- 条件2
条件判断
| = | value == "字符串",value == 数字 |
|---|---|
| < | value < 数字 |
| > | value > 数字 |
| <= | value <= 数字 |
| >= | value >= 数字 |
| != | value != 数字 |
is defined value;value is defined |
变量存在 |
is not defined ;value is not defined |
变量不存在 |
bool变量 为true value |
value的值为true |
bool变量 false not value |
value的值为false |
value in value2 |
value的值在value2列表中 |
多条条件组合
when：
条件1 and 条件2
- 条件1
- 条件2
when:
条件1 or 条件2
when: >
条件1
or
条件2
例题
检查受控主机是否安装了vsftpd，如果没有，输出没有安装，
并且安装vsftpd
---
- name: check vsftpd
hosts: 172.25.11.3
tasks:
- name: check vsftpd
shell: rpm -q vsftpd
register: vsftpd_state
ignore_errors: yes
- name: debug
debug:
msg: it is not installed vsftpd"
when: vsftpd_state.rc == 1
- name: dnf vsftpd
dnf:
name: vsftpd
state: present
when: vsftpd_stste.rc == 1
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三.触发器
| notify | 触发器当遇到更改是触发handlers |
|---|---|
| handlers： | 触发器触发后执行的动作 |
实例
1 apache虚拟机
---
- name: create virtualhost for web server
hosts: 172.25.11.254
vars_files:
./vhost_list.yml
tasks:
- name: create document
file:
path: "{
{web2.document}}"
state: directory
- name: create vhost.conf
copy:
dest: /etc/httpd/conf.d/vhost.conf
content:
"<VirtualHost *:{
{web1.port}}>\n\tServerName {
{web1.name}}\n\tDocumentRoot {
{web1.document}}\n\tCustomLog logs/{
{web1.name}}.log combined\n</VirtualHost>\n\n<VirtualHost *:{
{web2.port}}>\n\tServerName {
{web2.name}}\n\tDocumentRoot {
{web2.document}}\n\tCustomLog logs/{
{web2.name}}.log combined\n</VirtualHost>"
notify:
restart apache
handlers:
- name: restart apache
service:
name: httpd
state: restarted
2
查看受控主机是否有/dev/sdb，（虚拟机是vdb，此实验实在vmware中做的），如果有，进行分区，划分出来/dev/sdb，1G。并将其格式化，挂载到/westos.
- name: check sdb
hosts: 172.25.11.2
tasks:
- name: check
debug:
msg: "{
{ansible_facts.all_ipv4_addresses}} is not exist with /dev/sdb"
when: ansible_facts.devices.sdb is not defined
- name: parted
parted:
device: /dev/sdb
number: 1
state: present
part_end: 1GiB
when: ansible_facts.devices.sdb is defined
notify:
- filesystem
- mounted
handlers:
- name: filesystem
filesystem:
dev: /dev/sdb1
fstype: xfs
- name: mounted
mount:
path: /westos
src: /dev/sdb1
fstype: xfs
state: mounted
受控主机中查看实验效果
四.处理失败任务
1.ignore_errors
作用：
当play遇到任务失败是会终止
ignore_errors: yes 将会忽略任务失败使下面的任务继续运行
实例 (上文中多次应用：)
- name: test
dnf:
name: westos
state: latest
ignore_errors: yes
- name: create file
file:
path: /mnt/westos
state: touch
2.force_handlers
作用：
当任务失败后play被终止也会调用触发器进程
example
---
- name: apache change port
hosts: 172.25.11.254
force_handlers: yes
vars:
http_port: 80
tasks:
- name: configure apache conf file
lineinfile:
path: /etc/httpd/conf/httpd.conf
regexp: "^Listen"
line: "Listen {
{ http_port }}"
notify: restart apache
- name: install error ###没有westos服务，所以这部会出现错误，后续无法执行，force_handlers 强制执行
dnf:
name: westos
state: latest
handlers:
- name: restart apache
service:
name: httpd
state: restarted
enabled: yes
3.changed_when
作用：
控制任务在何时报告它已进行更改
1
---
- name: test
hosts: 172.25.11.2
tasks:
- name: shell
shell: echo hello
register: westos
changed_when: ture
---
- name: test
hosts: 172.25.11.2
tasks:
- name: shell
shell: echo hello
register: westos
changed_when: false
4.failed_when
当符合条件时强制任务失败
---
- name: test
hosts: 172.25.11.2
tasks:
- name: shell
shell: echo hello
register: westos
failed_when: "'hello' in westos.stdout"
5.block
| block | 定义要与运行的任务 |
|---|---|
| rescue: | 定义当block句子中出现失败任务后运行的任务 |
| always： | 定义最终独立运行的任务 |
测试练习
建立playbook ~/westos.yml要求如下:
建立大小为1500M名为/dev/vdb1的设备
如果/dev/vdb不存在请输入:
/dev/vdb is not exist
如果/dev/vdb大小不足2G请输出：
/dev/vdb is less then 2G
并建立800M大小的/dev/vdb1
此设备挂载到/westos上
sdb
- name: check sdb
hosts: all
tasks:
- name: check
debug:
msg: "{
{
ansible_facts.all_ipv4_addresses}} is not exist with /dev/sdb"
when: ansible_facts.devices.sdb is not defined
- name: create sdb1
block:
- name: create 1500M sdb1
parted:
device: /dev/sdb
number: 1
state: present
part_end: 1500 MiB
when: ansible_facts.devices.sdb is defined
notify:
- filesystem
- mounted
rescue:
- name: check /dev/sdb
debug:
msg: "{
{
ansible_facts.all_ipv4_addresses}} 's /dev/sdb is less than 1500M;
when: ansible_facts.devices.sdb is defined
- name: create /dev/sdb
parted:
device: /dev/sdb
number: 1
state: present
part_end: 800MiB
when: ansible_facts.devices.sdb is defined
notify:
- filesystem
- mounted
handlers:
- name: filesystem
filesystem:
dev: /dev/sdb1
fstype: xfs
- name: mounted
mount:
path: /westos
src: /dev/sdb1
fstype: xfs
state: mounted
注意：不同版本的虚拟机所列出的信息不一致
先使用 ansible ip -m setup 列出信息，
