Ansible学习笔记——facts变量
Ansible学习笔记——facts变量
- facts变量基础使用
-
- 使用adhoc（setup命令）查看facts
- 使用debug查看facts变量
- facts变量文件截取
- 在playbook中读取facts变量
- 关闭facts变量收集
- 自定义facts
- facts变量综合练习
-
- 要求
- 环境
- yml文件操作
facts变量：查看在被管理主机上的一些参数，例如主机名称、内核版本、网络接口、ip地址、系统版本、磁盘空间等
facts变量基础使用
使用adhoc（setup命令）查看facts
在这里插入代码片
使用debug查看facts变量
[student@workstation wangxc]$ cat facts.yml
---
- name: facts
hosts: servera
tasks:
- name: test facts
debug:
var: ansible_facts
facts变量文件截取
"ipv4": {
"address": "127.0.0.1",
"broadcast": "host",
"netmask": "255.0.0.0",
"network": "127.0.0.0"
},
"fibre_channel_wwn": [],
"fips": false,
"form_factor": "Other",
"fqdn": "servera.lab.example.com",
"gather_subset": [
"all"
],
"hostname": "servera",
"hostnqn": "",
"interfaces": [
"enp2s0",
"enp1s0",
"lo"
],
"is_chroot": false,
"iscsi_iqn": "",
"kernel": "4.18.0-80.el8.x86_64",
在playbook中读取facts变量
通过debug方法，读取主机名和ip地址
tasks:
- name: test facts
debug:
msg: >
the ipv4 address is {{ ansible_facts.fqdn }}
is {{ ansible_facts.default_ipv4.address }}
输出结果：
ok: [servera] => {
"msg": "the ipv4 address is servera.lab.example.com is 172.25.250.10\n"
}
关闭facts变量收集
如果确认playbook中没有任何地方使用到facts，可以选择关闭变量收集。这能够有效的提升playbook的运行速度和效率。
在task中加入如下片段
gather_facts: no
再次执行facts.yml会提示找不到变量
[student@workstation wangxc]$ ansible-playbook facts.yml
PLAY [facts] *************************************************************************************************************************
TASK [test facts] ********************************************************************************************************************
fatal: [servera]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'dict object' has no attribute 'fqdn'\n\nThe error appears to be in '/home/student/wangxc/facts.yml': line 6, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n tasks:\n - name: test facts\n ^ here\n"}
并且输出结果中已经没有下面这一行了
TASK [Gathering Facts] ***************************************************************************************************************
ok: [servera]
自定义facts
在被管理主机的 /etc/ansible/facts.d文件夹下新建一个以.fact结尾的文件，可以为json或ini格式。可写入自定义facts
[student@servera ~]$ cd /etc/ansible/facts.d/
[student@servera facts.d]$ ll
total 4
-rw-r--r--. 1 root root 44 Mar 16 17:52 servera.fact
[student@servera facts.d]$ cat servera.fact
{
"user":{
"name": "wangxc"
}
}
执行setup之后，可以从结果中查看到自定义facts
ansible servera -m setup >> 1.json
[student@workstation wangxc]$ vi 1.json
},
"ansible_local": {
"servera": {
"user": {
"name": "wangxc"
}
}
},
"ansible_lsb": {},
"ansible_lvm": {
"lvs": {},
facts变量综合练习
要求
- 在workstation机器上，创建custom.fact文件，并传输到webserver主机组中。目的是，在执行主playbook是可以读取webserver组中的自定义facts变量。
- 使用主playbook在webserver组中的主机上安装httpd服务，并启动。安装过程中需要使用到自定义facts变量。
环境
[student@workstation data-facts]$ cat ansible.cfg
[defaults]
inventory = inventory
remote_user = devops
[privilege_escalation]
become = true
[student@workstation data-facts]$ cat inventory
[webserver]
servera.lab.example.com
yml文件操作
1、创建custom.fact变量文件
[student@workstation data-facts]$ cat custom.fact
[general]
package = httpd
service = httpd
state = started
enabled = true
2、编写setup_facts.yml文件，在目标主机中创建文件夹，并将custom.fact文件拷贝过去
[student@workstation data-facts]$ cat setup_facts.yml
---
- name: install remote facts
hosts: webserver
vars:
remote_dir: /etc/ansible/facts.d
facts_file: custom.fact
tasks:
- name: create the remote directory
file:
state: directory
recurse: yes
path: "{{ remote_dir }}"
- name: install the new facts
copy:
src: "{{ facts_file }}"
dest: "{{ remote_dir }}"
3、使用setup命令，查看facts变量。导出到webserver.json中，查看没有自定义变量。
ansible webserver -m setup >>webserver.json
#自定义变量为空
"ansible_local": {}
4、执行setup_facts.yml文件，将变量文件传输到webserver中
5、查看webserver中的自定义变量
"ansible_local": {
"custom": {
"general": {
"enabled": "true",
"package": "httpd",
"service": "httpd",
"state": "started"
}
}
},
6、使用adhoc命令检查webserver中的httpd服务不存在
[student@workstation data-facts]$ ansible webserver -a 'systemctl status httpd'
servera.lab.example.com | FAILED | rc=4 >>
Unit httpd.service could not be found.non-zero return code
7、编写主playbook，使用自定义的fact变量安装软件包，并启动服务
[student@workstation data-facts]$ ansible-playbook playbook.yml
PLAY [install apache and start servers] **********************************************************************************************
TASK [Gathering Facts] ***************************************************************************************************************
ok: [servera.lab.example.com]
TASK [install the package] ***********************************************************************************************************
ok: [servera.lab.example.com]
TASK [start service] *****************************************************************************************************************
changed: [servera.lab.example.com]
PLAY RECAP ***************************************************************************************************************************
servera.lab.example.com : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
8、查看webserver的httpd状态，已启动
[student@workstation data-facts]$ ansible webserver -a 'systemctl status httpd'
servera.lab.example.com | CHANGED | rc=0 >>
● httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
Active: active (running) since Wed 2021-03-17 17:18:22 CST; 33min ago
Docs: man:httpd.service(8)
Main PID: 27884 (httpd)
Status: "Running, listening on: port 80"
Tasks: 213 (limit: 4956)
Memory: 46.1M
CGroup: /system.slice/httpd.service
├─27884 /usr/sbin/httpd -DFOREGROUND
├─27885 /usr/sbin/httpd -DFOREGROUND
├─27886 /usr/sbin/httpd -DFOREGROUND
├─27887 /usr/sbin/httpd -DFOREGROUND
└─27888 /usr/sbin/httpd -DFOREGROUND
Mar 17 17:18:22 servera.lab.example.com systemd[1]: Starting The Apache HTTP Server...
Mar 17 17:18:22 servera.lab.example.com httpd[27884]: Server configured, listening on: port 80
Mar 17 17:18:22 servera.lab.example.com systemd[1]: Started The Apache HTTP Server.