使用ansible部署缓存服务器

DNS缓存服务器是一种不负责域名数据维护的DNS服务器。简单来说，缓存服务器就是把用户经常使用到的域名与IP地址的解析记录保存在主机本地，从而提升下次解析的效率，这次使用unbound这款软件部署缓存服务器

一、 准备工作

1、 实验拓扑

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2、 unbound软件介绍

Unbound是红帽公司（RedHat）默认使用的的DNS服务包,Unbound是一个安全性高、功能强大、配置简单。

3、 使用参数说明

二、 ansible文件

1、 目录结构

[root@mmx_ansible dns_automating_unbound]# ls
ansible.cfg  inventory.yml  server.conf.j2  unbound.conf  unbound.yml

2、 配置文件

ansible.cfg

[defaults]
inventory=./inventory.yml
remote_user=root

3、主机清单文件

inventory.yml

home：
	caching_dns:
      ansible_host: 192.168.0.100
      ansible_ssh_password: "密码"
      ansible_user: "用户名"

4、 模板文件

server.conf.j2

{# 通过列举出所有的ipv4地址，来写 #}
server:
{% for ip in ansible_facts['all_ipv4_addresses'] %}
    interface: {{ ip }}
{% endfor %}

    interface-automatic: no
    access-control: {{ access_control }}
    domain-insecure: {{ domain_insecure }}

forward-zone:
    name: "{{ forward_zone_name }}"
    forward-addr: {{ forward_addr }}

5、 playbook

unbound.yml

---
- name: ubound is deployed on caching nameservers
  hosts: caching_dns
  become: yes
  vars:
    forward_addr: "114.114.114.114"
    access_control: "0.0.0.0/0 allow"
    domain_insecure: "*"
    forward_zone_name: "."

  tasks:
    - name: unbound is installed(安装软件包)
      yum:
        name: unbound
        state: present

    - name: unbound configuration is correct(配置unbound文件，当修改该文件时，重启服务)
      template:
        src: server.conf.j2
        dest: /etc/unbound/conf.d/server.conf
        owner: root
        group: unbound
        mode: '0644'
        setype: named_conf_t
      notify:
        - restart unbound
    
    - name: unbound is started and enabled(开启&&开机启动unbound服务)
      service:
        name: unbound
        state: started
        enabled: yes
    
    - name: unbound is started and enabled(开启&&开机启动unbound服务)
      service:
        name: firewalld
        state: started
        enabled: yes
    
    - name: dns is enabled on the firewalld(放行unbound服务)
      ansible.posix.firewalld:
        service: dns
        state: enabled
        permanent: yes
        immediate: yes
  
  handlers:
      # 重启unbound服务
    - name: restart unbound
      service:
        name: unbound
        state: restarted

6、 执行playbook

ansible-playbook unbound.yml

[root@mmx_ansible dns_automating_unbound]# ansible-playbook unbound.yml 

PLAY [ubound is deployed on caching nameservers] *************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ***************************************************************************************************************************************************************************************************************************
ok: [caching_dns]

TASK [unbound is installed(安装软件包)] **********************************************************************************************************************************************************************************************************
ok: [caching_dns]

TASK [unbound configuration is correct(配置unbound文件，当修改该文件时，重启服务)] ***************************************************************************************************************************************************************
ok: [caching_dns]

TASK [unbound is started and enabled(开启&&开机启动unbound服务)] *********************************************************************************************************************************************************************************
ok: [caching_dns]

TASK [unbound is started and enabled(开启&&开机启动unbound服务)] *********************************************************************************************************************************************************************************
ok: [caching_dns]

TASK [dns is enabled on the firewalld(放行unbound服务)] ******************************************************************************************************************************************************************************************
ok: [caching_dns]

PLAY RECAP ***************************************************************************************************************************************************************************************************************************************
caching_dns                : ok=6    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

三、测试

1、 客户端

1） 临时修改客户端DNS地址

[root@dns_client ~]# vim /etc/resolv.conf
nameserver 192.168.0.100

2） nslookup访问百度

[root@dns_client ~]# nslookup www.baidu.com
Server:         192.168.0.100
Address:        192.168.0.100#53

Non-authoritative answer:
www.baidu.com   canonical name = www.a.shifen.com.
Name:   www.a.shifen.com
Address: 182.61.200.7
Name:   www.a.shifen.com
Address: 182.61.200.6

2、 缓存服务器

1 ) 查看修改的配置文件

[root@DNS-Server_ubound ~]# cat /etc/unbound/conf.d/server.conf
server:
    interface: 192.168.0.100

    interface-automatic: no
    access-control: 0.0.0.0/0 allow
    domain-insecure: *

forward-zone:
    name: "."
    forward-addr: 114.114.114.114

2）查看缓存

unbound-control dump_cache

[root@DNS-Server_ubound ~]# unbound-control dump_cache
START_RRSET_CACHE
;rrset 155 1 0 2 3
a.shifen.com.   155     IN      SOA     ns1.a.shifen.com. baidu_dns_master.baidu.com. 2301200016 5 5 2592000 3600
;rrset 125 2 0 5 3
www.a.shifen.com.       125     IN      A       182.61.200.6
www.a.shifen.com.       125     IN      A       182.61.200.7
;rrset 545 1 0 5 3
www.baidu.com.  545     IN      CNAME   www.a.shifen.com.
END_RRSET_CACHE
START_MSG_CACHE
msg www.a.shifen.com. IN AAAA 33152 1 155 3 0 1 0
a.shifen.com. IN SOA 4
msg www.baidu.com. IN A 33152 1 125 3 2 0 0
www.baidu.com. IN CNAME 0
www.a.shifen.com. IN A 0
msg www.a.shifen.com. IN A 33152 1 125 0 1 0 0
www.a.shifen.com. IN A 0
END_MSG_CACHE
EOF