个人笔记Ansible：facts变量
一、概念
shell变量：
定义： Host=oldxu.com
使用：${Host}
Ansible变量：
定义： Host=oldxu.com
使用：{{ Host }}
变量：以一个固定的字符串去表示一个不固定的值
那么在Ansible中定义变量分为如下三种方式:
1. 通过命令行进行变量定义
2. 在play文件中进行定义变量
3. 通过inventory在主机组或单个主机中设置变量
变量的优先级（ 变量读取的顺序 ）
二、
1.通过play文件中进行变量定义：
通过vars来进行定义变量
[root@manager ansible_variables]# cat var1.yml
- hosts: webservers
vars: #定义变量关键字
- web_packages: httpd
- ftp_packages: vsftpd
tasks:
- name: Installed Rpm Packages "{{ web_packages }}" "{{ ftp_packages }}"
yum:
name:
- "{{ web_packages }}"
- "{{ ftp_packages }}"
state: present
注意：vars关键字定义的变量，无法与其他的playbook进行共享。
通过vars_files来进行定义变量
[root@manager ansible_variables]# cat test.yml
web_packages: httpd-tools
ftp_packages: vsftpd
[root@manager ansible_variables]# cat var1.yml
- hosts: webservers
vars_files: test.yml
tasks:
- name: Installed Rpm Packages "{{ web_packages }}" "{{ ftp_packages }}"
yum:
name:
- "{{ web_packages }}"
- "{{ ftp_packages }}"
state: present
[root@manager ansible_variables]# cat var2.yml
- hosts: webservers
vars_files: test.yml
tasks:
- name: Installed Rpm Packages "{{ web_packages }}" "{{ ftp_packages }}"
yum:
name:
- "{{ web_packages }}"
- "{{ ftp_packages }}"
state: present
2.通过inventory在主机组或单个主机中设置变量
[root@manager ansible_variables]# mkdir host_vars
[root@manager ansible_variables]# mkdir group_vars
[root@manager ansible_variables]# cat group_vars/webservers
web_packages: wget
ftp_packages: tree
[root@manager ansible_variables]# cat var4.yml
- hosts: webservers
tasks:
- name: Install Rpm Packages "{{ web_packages }}" "{{ ftp_packages }}"
yum:
name:
- "{{ web_packages }}"
- "{{ ftp_packages }}"
state: present
[root@manager ansible_variables]# cat group_vars/all
web_packages: nfs-utils
ftp_packages: rsync
[root@manager ansible_variables]# cat var5.yml
- hosts: db
tasks:
- name: Install Rpm Packages "{{ web_packages }}" "{{ ftp_packages }}"
yum:
name:
- "{{ web_packages }}"
- "{{ ftp_packages }}"
state: present
3.通过命令行进行变量定义
[root@manager ansible_variables]# cat var6.yml
- hosts: webservers
tasks:
- name: Install Rpm Packages "{{ test_packages }}"
yum:
name:
- "{{ test_packages }}"
state: present
[root@manager ansible_variables]# ansible-playbook var6.yml -e "test_packages=sl"
变量的查找顺序：
设定同一个变量，不同的值，去测试，看谁优先被使用。
filename=
1）在plabook中定义vars变量
2）在playbook中定义vars_files变量
3）在host_vars中定义变量
4）在group_vars中定义变量
5）通过执行命令传递变量
变量的查找优先级：
1.外置传参 -e
2.playbook
vars_files
vars
3.host_vars
4.group_vars/组名
4.group_vars/all
NFS服务端和NFS客户端，要求灵活。
[root@manager ansible_variables]# cat group_vars/all
share_dir: /data3
[root@manager ansible_variables]# cat var8.yml
- hosts: webservers
tasks:
- name: Installed NFS Server
yum:
name: nfs-utils
- name: Configure NFS Server #配置文件中使用 了share_dir #共享的目录/data3
template:
src: ./exports.j2
dest: /etc/exports
notify: Restart NFS Server
- name: Create Share Directory #创建共享的目录使用share_dir /data3
file:
path: "{{ share_dir }}"
state: directory
owner: www
group: www
mode: 755
- name: Started NFS Server
systemd:
name: nfs
state: started
enabled: yes
handlers:
- name: Restart NFS Server
systemd:
name: nfs
state: restarted
- hosts: db
tasks:
- name: Client Mount NFS Server
mount:
src: 172.16.1.7:{{ share_dir }}
path: /ansible_mount
fstype: nfs
state: mounted
register变量注册，将执行的结果存储至变量中，后期可以通过结果进行判断的操作。
[root@manager ansible_variables]# cat var9.yml
- hosts: webservers
tasks:
- name: Get Network Status
shell: netstat -lntp
register: System_Net
#将shell命令的执行输出结果，存储至System_Net变量中
- name: Print Variables
debug:
msg: "{{ System_Net.stdout_lines }}"
{{ System_Net }} 能看到变量的所有信息
{{ System_Net.stderr }} #能捕获到错误，如果没有就是空，如果有错误就会限制在终端窗口
三、facts变量实战
1.根据IP地址生成不同的Redis配置
web01 bind 172.16.1.7
web02 bind 172.16.1.8
[root@manager ansible_variables]# cat redis.yml
- hosts: webservers
tasks:
- name: Installed Redis Server
yum:
name: redis
state: present
- name: Configure Redis Server
template:
src: ./redis.conf.j2
dest: /etc/redis.conf
notify: Restart Redis Server
- name: Started Redis Server
systemd:
name: redis
state: started
enabled: yes
handlers:
- name: Restart Redis Server
systemd:
name: redis
state: restarted
[root@manager ansible_variables]# cat redis.conf.j2
bind 127.0.0.1 {{ ansible_eth1.ipv4.address }}
2.根据CPU核心生成不同的Nginx配置
web01 1核心 1GB 2
web02 2核心 2GB 4
[root@manager ansible_variables]# cat nginx.yml
- hosts: webservers
tasks:
- name: Configure Nginx.conf
template:
src: ./nginx.conf.j2
dest: /tmp/nginx.conf
[root@manager ansible_variables]# cat nginx.conf.j2
worker {{ ansible_processor_vcpus * 2 }};
3.根据主机内存生成不同的Memcached配置 ( 使用物理内存的一半 )
web01 1G 512
web02 2G 1024
web03 4G 2048
- 找到物理内存的变量
- 将变量除以2
[root@manager ansible_variables]# yum install memcached -y
[root@manager ansible_variables]# cp /etc/sysconfig/memcached ./memcached.j2
[root@manager ansible_variables]# cat memcached.j2
PORT="11211"
USER="memcached"
MAXCONN="1024"
CACHESIZE="{{ ansible_memtotal_mb //2 }}"
OPTIONS=""
[root@manager ansible_variables]# cat memcached.yml
- hosts: webservers
tasks:
- name: Installed Memcached Server
yum:
name: memcached
state: present
- name: Configure Memcached Server
template:
src: memcached.j2
dest: /etc/sysconfig/memcached
notify: Restart Memcached Server
- name: Started Memcached Server
systemd:
name: memcached
state: started
enabled: yes
handlers:
- name: Restart Memcached Server
systemd:
name: memcached
state: restarted
4.根据主机名称生成不同的zabbix配置
[root@manager ansible_variables]# cat zabbix_agent.yml
- hosts: all
tasks:
- name: Installed ZabbixAgent
yum:
name: https://mirror.tuna.tsinghua.edu.cn/zabbix/zabbix/4.0/rhel/7/x86_64/zabbix-agent-4.0.0-2.el7.x86_64.rpm
state: present
- name: Configure ZabbixAgent
template:
src: ./zabbix_agentd.conf.j2
dest: /etc/zabbix/zabbix_agentd.conf
notify: Restart ZabbixAgent
- name: Started ZabbixAgent
systemd:
name: zabbix-agent
state: started
enabled: yes
handlers:
- name: Restart ZabbixAgent
systemd:
name: zabbix-agent
state: restarted
[root@manager ansible_variables]# grep "^Hostname" zabbix_agentd.conf.j2
Hostname={{ ansible_hostname }}
四、facts优化
facts变量开启会影响playbook运行的效率？ 但是关闭又会造成无法提取被控端的状态。 最佳的方案使用缓存来解决。
-
没有使用缓存时的时间： 4台机器同时操作： 20台
real 0m28.738s user 0m12.064s sys 0m3.725s -
增加redis缓存：
real 0m6.345s user 0m3.021s sys 0m1.039s
1.安装一个redis 172.16.1.51 安装过了，就不要需要安装，直接使用就行了。
2.配置ansible配置文件，让其支持redis缓存：
[root@manager ansible_variables]# cat ansible.cfg
[defaults]
inventory = ./hosts
gathering = smart
fact_caching_timeout = 86400
fact_caching = redis
fact_caching_connection = 172.16.1.7:6379
yum install python-pip
pip install redis