[Ansible系列⑥]Ansible变量详解
一. 简介
ansible支持变量，用于存储会在整个项目中重复使用到的一些值。以简化项目的创建与维护，降低出错的机率。
变量的定义：
- 变量名应该由字母、数字下划数组成
- 变量名必须以字母开头
- ansible内置关键字不能作为变量名
二. Inventory中定义变量
2.1 定义主机变量
定义方式：在inventory清单中，主机名称或主机ip后面 写定义变量。
使用范围：对应的主机才能使用该变量
inventory清单文件：
[root@clinet test1]# cat hosts
[web]
10.10.10.135 ansible_ssh_port=22 state=master
10.10.10.134 ansible_ssh_port=22 state=backup
yaml文件
[root@clinet test1]# cat vars.yml
- hosts: web
tasks:
- name: debug message..
debug:
msg:
- '{{ ansible_ssh_port }}'
- '{{ state }}'
执行结果：
[root@clinet test1]# ansible-playbook vars.yml
PLAY [web] ***********************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.134]
ok: [10.10.10.135]
TASK [debug message..] ***********************************************************************************************
ok: [10.10.10.135] => {
"msg": [
22,
"master"
]
}
ok: [10.10.10.134] => {
"msg": [
22,
"backup"
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.134 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.135 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#
2.2 定义主机组变量
定义方式：[组名：vars]后面接定义的变量
使用访问：组内的主机都可以使用该变量
inventory清单文件：
[root@clinet test1]# cat hosts
[db]
10.10.10.135
10.10.10.136
[db:vars]
ntp_server=aliyun1.ntp.com
proxy=nginx_proxy
yaml文件
[root@clinet test1]# cat vars.yml
- hosts: db
tasks:
- name: debug message..
debug:
msg:
- '{{ ntp_server }}'
- '{{ proxy }}'
[root@clinet test1]# ansible-playbook vars.yml
PLAY [db] ************************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.135]
ok: [10.10.10.136]
TASK [debug message..] ***********************************************************************************************
ok: [10.10.10.135] => {
"msg": [
"aliyun1.ntp.com",
"nginx_proxy"
]
}
ok: [10.10.10.136] => {
"msg": [
"aliyun1.ntp.com",
"nginx_proxy"
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.135 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.136 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#
三. 在Playbook中定义变量
3.1 vars 关键字定义
定义方式： 在playbook中通过vars关键字定义变量。
使用范围：该playbook范围中。
inventory清单文件：
[root@clinet test1]# cat hosts
[db]
10.10.10.135
10.10.10.136
yaml文件
[root@clinet test1]# cat vars.yml
- hosts: db
vars:
http_port: 80
dns_port: 53
tasks:
- name: debug message..
debug:
msg:
- '{{ http_port }}'
- '{{ dns_port }}'
执行结果：
[root@clinet test1]# ansible-playbook vars.yml
PLAY [db] ************************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.135]
ok: [10.10.10.136]
TASK [debug message..] ***********************************************************************************************
ok: [10.10.10.135] => {
"msg": [
80,
53
]
}
ok: [10.10.10.136] => {
"msg": [
80,
53
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.135 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.136 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#3.2 通过vars_files关键字引入变量文件
方法一：
##定义vars_files
[root@clinet test1]# cat vars_file.yml
users:
bjones:
first_name: bob
last_name: jons
home_dirs: /users/bjones
acook:
first_name: Anne
last_name: Cook
home_dirs: /users/accok
##yml文件
[root@clinet test1]# cat vars.yml
- hosts: db
vars_files:
- /root/ansibel-test/test1/vars_file.yml ##最好为绝对路径
tasks:
- name: debug message..
debug:
msg:
- '{{ users["bjones"] ["first_name"]}}' ##主要两个[]之间有个空格
四. host_vars和group_vars定义变量
4.1 host_vars定义变量
在项目目录中创建host_vars目录，然后创建文件，文件的名称要与inventory清单中的主机名称保持一致，如果是ip地址，则创建相同ip地址的文件即可。
定义host_vars变量
[root@clinet test1]# cat host_vars/10.10.10.134
hostname: Route
ip_add: 10.10.10.134
[root@clinet test1]# cat host_vars/10.10.10.135
hostname: lvs_1
ip_add: 10.10.10.135
[root@clinet test1]#
编写yml文件
[root@clinet test1]#
[root@clinet test1]# cat vars.yml
- hosts: web
tasks:
- name: debug message..
debug:
msg:
- '{{ hostname }}'
- '{{ ip_add }}'
[root@clinet test1]#
执行结果
[root@clinet test1]# ansible-playbook vars.yml
PLAY [web] ***********************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.134]
ok: [10.10.10.135]
TASK [debug message..] ***********************************************************************************************
ok: [10.10.10.135] => {
"msg": [
"lvs_1",
"10.10.10.135"
]
}
ok: [10.10.10.134] => {
"msg": [
"Route",
"10.10.10.134"
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.134 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.135 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#4.2 定义group_vars变量
在项目目录中创建group_vars目录，然后创建一个文件，文件的文件名称要与inventory清单中的组名称保持一致。
定义group_vars
[root@clinet test1]# cat group_vars/web
group_name: web_group
[root@clinet test1]# cat group_vars/db
group_name: db_group
[root@clinet test1]#
编写yml文件
[root@clinet test1]# cat vars.yml
- hosts: db:web
tasks:
- name: debug message..
debug:
msg:
- '{{ group_name }}'
[root@clinet test1]#
执行结果
[root@clinet test1]# ansible-playbook vars.yml
PLAY [db:web] ********************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.134]
ok: [10.10.10.135]
ok: [10.10.10.136]
TASK [debug message..] ***********************************************************************************************
ok: [10.10.10.135] => {
"msg": [
"web_group"
]
}
ok: [10.10.10.134] => {
"msg": [
"web_group"
]
}
ok: [10.10.10.136] => {
"msg": [
"db_group"
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.134 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.135 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.136 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#变量优先级总结：
命令行变量-->playbook中vars_files-->paybook中vars-->inventory中hosts-->host_vars-->group_vars-->group_vars/all --->inventory中group
五. register变量
register关键字可以将某个task任务执行的结果存储在变量中，最后使用debug输出内容，可以用于后续的故障排查。
示例1：
[root@clinet test1]# cat vars.yml
- hosts: db:web
tasks:
- name: debug message..
shell: netstat -ntpl
register: system_info
- name: get_info
debug:
msg:
- '{{ system_info}}'
[root@clinet test1]#
执行结果：
[root@clinet test1]# ansible-playbook vars.yml
PLAY [db:web] ********************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.134]
ok: [10.10.10.135]
ok: [10.10.10.136]
TASK [debug message..] ***********************************************************************************************
changed: [10.10.10.134]
changed: [10.10.10.135]
changed: [10.10.10.136]
TASK [get_info] ******************************************************************************************************
ok: [10.10.10.135] => {
"msg": [
{
"changed": true,
"cmd": "netstat -ntpl",
"delta": "0:00:00.009932",
"end": "2022-10-28 16:38:44.957768",
"failed": false,
"rc": 0,
"start": "2022-10-28 16:38:44.947836",
"stderr": "",
"stderr_lines": [],
"stdout": "Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1523/sshd \ntcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1702/master \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 957/rpcbind \ntcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1558/nginx: master \ntcp6 0 0 :::22 :::* LISTEN 1523/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1702/master \ntcp6 0 0 :::111 :::* LISTEN 957/rpcbind \ntcp6 0 0 :::80 :::* LISTEN 1558/nginx: master ",
"stdout_lines": [
"Active Internet connections (only servers)",
"Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name ",
"tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1523/sshd ",
"tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1702/master ",
"tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 957/rpcbind ",
"tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1558/nginx: master ",
"tcp6 0 0 :::22 :::* LISTEN 1523/sshd ",
"tcp6 0 0 ::1:25 :::* LISTEN 1702/master ",
"tcp6 0 0 :::111 :::* LISTEN 957/rpcbind ",
"tcp6 0 0 :::80 :::* LISTEN 1558/nginx: master "
]
}
]
}
ok: [10.10.10.136] => {
"msg": [
{
"changed": true,
"cmd": "netstat -ntpl",
"delta": "0:00:00.021772",
"end": "2022-10-28 16:38:45.896962",
"failed": false,
"rc": 0,
"start": "2022-10-28 16:38:45.875190",
"stderr": "",
"stderr_lines": [],
"stdout": "Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 997/rpcbind \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1533/sshd \ntcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1716/master \ntcp6 0 0 :::111 :::* LISTEN 997/rpcbind \ntcp6 0 0 :::22 :::* LISTEN 1533/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1716/master ",
"stdout_lines": [
"Active Internet connections (only servers)",
"Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name ",
"tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 997/rpcbind ",
"tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1533/sshd ",
"tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1716/master ",
"tcp6 0 0 :::111 :::* LISTEN 997/rpcbind ",
"tcp6 0 0 :::22 :::* LISTEN 1533/sshd ",
"tcp6 0 0 ::1:25 :::* LISTEN 1716/master "
]
}
]
}
ok: [10.10.10.134] => {
"msg": [
{
"changed": true,
"cmd": "netstat -ntpl",
"delta": "0:00:00.008834",
"end": "2022-10-28 16:38:45.406496",
"failed": false,
"rc": 0,
"start": "2022-10-28 16:38:45.397662",
"stderr": "",
"stderr_lines": [],
"stdout": "Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1557/nginx: master \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1525/sshd \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1117/rpcbind \ntcp6 0 0 :::80 :::* LISTEN 1557/nginx: master \ntcp6 0 0 :::22 :::* LISTEN 1525/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1701/master \ntcp6 0 0 :::111 :::* LISTEN 1117/rpcbind ",
"stdout_lines": [
"Active Internet connections (only servers)",
"Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name ",
"tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1557/nginx: master ",
"tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1525/sshd ",
"tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1117/rpcbind ",
"tcp6 0 0 :::80 :::* LISTEN 1557/nginx: master ",
"tcp6 0 0 :::22 :::* LISTEN 1525/sshd ",
"tcp6 0 0 ::1:25 :::* LISTEN 1701/master ",
"tcp6 0 0 :::111 :::* LISTEN 1117/rpcbind "
]
}
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.134 : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.135 : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.136 : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]#
也可以只打印register变量中的子变量
[root@clinet test1]# cat vars.yml
- hosts: db:web
tasks:
- name: debug message..
shell: netstat -ntpl
register: system_info
- name: get_info
debug:
msg:
- '{{ system_info.start }}'
- name: get_info2
debug:
msg:
- '{{ system_info.stdout }}'
[root@clinet test1]#
结果
[root@clinet test1]# ansible-playbook vars.yml
PLAY [db:web] ********************************************************************************************************
TASK [Gathering Facts] ***********************************************************************************************
ok: [10.10.10.134]
ok: [10.10.10.135]
ok: [10.10.10.136]
TASK [debug message..] ***********************************************************************************************
changed: [10.10.10.135]
changed: [10.10.10.134]
changed: [10.10.10.136]
TASK [get_info] ******************************************************************************************************
ok: [10.10.10.135] => {
"msg": [
"2022-10-28 16:47:06.690457"
]
}
ok: [10.10.10.136] => {
"msg": [
"2022-10-28 16:47:07.616910"
]
}
ok: [10.10.10.134] => {
"msg": [
"2022-10-28 16:47:07.158014"
]
}
TASK [get_info2] *****************************************************************************************************
ok: [10.10.10.135] => {
"msg": [
"Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1523/sshd \ntcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1702/master \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 957/rpcbind \ntcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1558/nginx: master \ntcp6 0 0 :::22 :::* LISTEN 1523/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1702/master \ntcp6 0 0 :::111 :::* LISTEN 957/rpcbind \ntcp6 0 0 :::80 :::* LISTEN 1558/nginx: master "
]
}
ok: [10.10.10.136] => {
"msg": [
"Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 997/rpcbind \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1533/sshd \ntcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1716/master \ntcp6 0 0 :::111 :::* LISTEN 997/rpcbind \ntcp6 0 0 :::22 :::* LISTEN 1533/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1716/master "
]
}
ok: [10.10.10.134] => {
"msg": [
"Active Internet connections (only servers)\nProto Recv-Q Send-Q Local Address Foreign Address State PID/Program name \ntcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1557/nginx: master \ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1525/sshd \ntcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1117/rpcbind \ntcp6 0 0 :::80 :::* LISTEN 1557/nginx: master \ntcp6 0 0 :::22 :::* LISTEN 1525/sshd \ntcp6 0 0 ::1:25 :::* LISTEN 1701/master \ntcp6 0 0 :::111 :::* LISTEN 1117/rpcbind "
]
}
PLAY RECAP ***********************************************************************************************************
10.10.10.134 : ok=4 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.135 : ok=4 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
10.10.10.136 : ok=4 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@clinet test1]# 结束语：
本章重点要理解各种变量的定义方法，以及变量的使用优先级，在后续大型的项目playbook中使用的非常频繁；同时register变量也需要理解，有助于后续的排查故障，可特定的playbook的语法使用，比如接收register的自变量结果之后通过when去判断等等。