更新时间:2022-10-03 14:14:50
一、背景介绍
在日常工作中,为解决内网域名解析问题,时长会配置DNS服务来提供解析。这时DNS服务就起到了为所有内部服务提供连通的基础,变得非常重要了。所以在服务启动后还是应该考虑服务的高可用和数据的完整性。
网友有很多LVS+Keepalived+Bind的负载均衡高可用的解决方案,非常不错。不过自建DNS常用在公司内部平台之间的调用,所以负载均衡的意义并不是太大。当然,高可用还是需要保证的。本文章介绍通过Keepalived+Bind实现高可用主从同步DNS服务
二、基础环境
Master DNS:10.61.100.51
Slave DNS:10.61.100.52
VIP:10.61.100.50
三、bind配置
3.1、安装bind(主从)
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# yum install bind bind-chroot 安装包的作用就不做过多的介绍了 |
安装完成后会生成下面的文件
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[root@ip-10-61-100-51 ~] # ll /var/named/chroot/
总用量 20 drwxr-x--- 2 root named 4096 7月 11 16:55 dev drwxr-x--- 5 root named 4096 7月 11 19:31 etc drwxr-xr-x 2 root root 4096 7月 11 19:31 lib64 drwxr-xr-x 3 root root 4096 7月 11 16:55 usr drwxr-x--- 6 root named 4096 7月 11 16:55 var [root@ip-10-61-100-51 ~] # ll /etc/named.conf
-rw-r----- 1 root named 1311 7月 11 17:39 /etc/named .conf
其中 /etc/named .conf其实就是 /var/named/chroot/etc/named .conf,在启动后会在 /var/named/chroot/etc 生成相关配置文件。
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3.2、创建named.conf配置文件(主从都要配置,从配置在下面给出)
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vim /etc/named .conf
options { directory "/var/named" ;
listen-on { any; };
version "[wowoohr-1.0]" ;
forwarders { 202.96.209.5;
114.114.114.114;
};
recursion yes ;
allow-query {0.0.0.0 /0 ;};
}; logging{ channel default_log { file "/etc/log/dns-default.log" versions 10 size 1m;
severity info;
}; channel lamer_log { file "/etc/log/dns-lamer.log" versions 3 size 1m;
severity info;
print-severity yes ;
print- time yes ;
print-category yes ;
}; channel query_log { file "/etc/log/dns-query.log" versions 10 size 10m;
severity info;
}; channel security_log { file "/etc/log/dns-security.log" versions 3 size 1m;
severity info;
print-severity yes ;
print- time yes ;
print-category yes ;
}; category lame-servers { lamer_log; }; category security { security_log; }; category queries { query_log; }; category default { default_log; }; }; zone "." {
type hint;
file "/etc/named.root" ;
};
zone "myshebao.com" {
type master;
file "/etc/master/test.com.zone " ;
allow-transfer { 10.61.100.52; };
};
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3.3、创建named.root配置文件(主从都要配置且配置一样,故从配置不在给出)
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[root@ip-10-61-100-51 etc] # cat named.root
; This file holds the information on root name servers needed to
; initialize cache of Internet domain name servers ; ; This file is made available by InterNIC
; under anonymous FTP as ; file /domain/named .root
; on server FTP.INTERNIC.NET ; -OR- RS.INTERNIC.NET ; ; last update: Jan 29, 2004 ; related version of root zone: 2004012900 ; ; ; formerly NS.INTERNIC.NET ; . 3600000 IN NS A.ROOT-SERVERS.NET. A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4 ; ; formerly NS1.ISI.EDU ; . 3600000 NS B.ROOT-SERVERS.NET. B.ROOT-SERVERS.NET. 3600000 A 192.228.79.201 ; ; formerly C.PSI.NET ; . 3600000 NS C.ROOT-SERVERS.NET. C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12 ; ; formerly TERP.UMD.EDU ; . 3600000 NS D.ROOT-SERVERS.NET. D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90 ; ; formerly NS.NASA.GOV ; . 3600000 NS E.ROOT-SERVERS.NET. E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10 ; ; formerly NS.ISC.ORG ; . 3600000 NS F.ROOT-SERVERS.NET. F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241 ; ; formerly NS.NIC.DDN.MIL ; . 3600000 NS G.ROOT-SERVERS.NET. G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4 . 3600000 NS E.ROOT-SERVERS.NET. E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10 ; ; formerly NS.ISC.ORG ; . 3600000 NS F.ROOT-SERVERS.NET. F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241 ; ; formerly NS.NIC.DDN.MIL ; . 3600000 NS G.ROOT-SERVERS.NET. G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4 ; ; formerly AOS.ARL.ARMY.MIL ; . 3600000 NS H.ROOT-SERVERS.NET. H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53 ; ; formerly NIC.NORDU.NET ; . 3600000 NS I.ROOT-SERVERS.NET. I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17 ; ; operated by VeriSign, Inc. ; . 3600000 NS J.ROOT-SERVERS.NET. J.ROOT-SERVERS.NET. 3600000 A 192.58.128.30 ; ; operated by RIPE NCC ; . 3600000 NS K.ROOT-SERVERS.NET. K.ROOT-SERVERS.NET. 3600000 A 193.0.14.129 ; ; operated by ICANN ; . 3600000 NS L.ROOT-SERVERS.NET. L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12 ; ; operated by WIDE ; . 3600000 NS M.ROOT-SERVERS.NET. M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33 ; End of File |
3.4、根据配置文件创建相关目录(主配置)
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[root@ip-10-61-100-51 etc] # cd /var/named/chroot/etc/
[root@ip-10-61-100-51 etc] # mkdir log master
[root@ip-10-61-100-51 etc] # chown named:named log/ -R
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3.5、创建zone区域文件(主配置)
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[root@ip-10-61-100-51 etc] # vim master/test.com.zone
$TTL 1D @ IN SOA ns1. test .com. yull. test .com. (
2017071104 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
IN NS ns1. test .com.
IN NS ns2. test .com.
ns1 IN A 10.61.100.51 ns2 IN A 10.61.100.52 redis IN A 10.61.100.51 db IN A 10.61.100.53 |
3.6、启动named服务(主配置)
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# service named start |
3.7、从服务器named.conf配置。注意从服务器也需要named.root文件
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[root@ip-10-61-100-52 ~] # cat /etc/named.conf
options { directory "/var/named" ;
listen-on { any; };
version "[wowoohr-1.0]" ;
forwarders { 202.96.209.5;
114.114.114.114;
};
recursion yes ;
allow-query {0.0.0.0 /0 ;};
}; logging{ channel default_log { file "/etc/log/dns-default.log" versions 10 size 1m;
severity info;
}; channel lamer_log { file "/etc/log/dns-lamer.log" versions 3 size 1m;
severity info;
print-severity yes ;
print- time yes ;
print-category yes ;
}; channel query_log { file "/etc/log/dns-query.log" versions 10 size 10m;
severity info;
}; channel security_log { file "/etc/log/dns-security.log" versions 3 size 1m;
severity info;
print-severity yes ;
print- time yes ;
print-category yes ;
}; category lame-servers { lamer_log; }; category security { security_log; }; category queries { query_log; }; category default { default_log; }; }; zone "." {
type hint;
file "/etc/named.root" ;
};
zone "myshebao.com" {
type slave;
file "/etc/slave/test.com.zone" ;
masters {
10.61.100.51;
};
allow-transfer { none; };
};
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3.8、创建相关目录文件(从)
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[root@ip-10-61-100-52 etc] # cd /var/named/chroot/etc/
[root@ip-10-61-100-52 etc] # mkdir log slave
[root@ip-10-61-100-52 etc] # chown named:named log/ -R
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3.9、启动named服务(从)
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# service named start |
如成功配置,则会在从的/var/named/chroot/etc/slave下同步test.com.zone配置文件。
四、Keepalived高可用配置
4.1、安装Keepalived(主从)
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# yum -y install keepalived |
4.2、修改配置文件
设计思路:
当 Master 与 Slave 均运作正常时, Master负责服务,Slave负责Standby;
当 Master 挂掉,Slave 正常时, Slave接管服务;
当 Master 恢复正常,恢复Master身份
然后依次循环。需要注意的是修改数据只能在Master修改。
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[root@ip-10-61-100-51 etc] # cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs { notification_email {
yu.liang.liang@wowoohr.com
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
} vrrp_script chk_dns { script "/etc/keepalived/scripts/dns_check.sh"
interval 2
} vrrp_instance V_DNS { state MASTER
interface eth0
virtual_router_id 153
priority 100 #从服务器修改为80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_dns
}
virtual_ipaddress {
10.61.100.50
}
notify_master /etc/keepalived/scripts/dns_master .sh
notify_backup /etc/keepalived/scripts/dns_backup .sh
notify_fault /etc/keepalived/scripts/dns_fault .sh
notify_stop /etc/keepalived/scripts/dns_stop .sh
} |
上述中的脚本因为Keepalived在转换状态时会依照状态来呼叫:
通过dns_check.sh来检测服务可用性
当进入Master状态时会呼叫notify_master
当进入Backup状态时会呼叫notify_backup
当发现异常情况时进入Fault状态呼叫notify_fault
当Keepalived程序终止时则呼叫notify_stop
4.3、编辑相关脚本(主从)
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# vim /etc/keepalived/scripts/dns_check.sh #!/bin/bash ALIVE=` netstat -ntpl | grep "53" `
if [ $? == 0 ]; then
exit 0
else exit 1
fi |
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# vim /etc/keepalived/scripts/dns_master.sh LOGFILE= "/var/log/keepalived-dns-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "Run reload cmd ..." >> $LOGFILE
service named reload >> $LOGFILE 2>&1 |
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# vim /etc/keepalived/scripts/dns_backup.sh LOGFILE= "/var/log/keepalived-dns-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
service named reload >> $LOGFILE 2>&1 echo "Being slave...." >> $LOGFILE 2>&1
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# vim /etc/keepalived/scripts/dns_fault.sh #!/bin/bash LOGFILE= /var/log/keepalived-dns-state .log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE
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# vim /etc/keepalived/scripts/dns_stop.sh #!/bin/bash LOGFILE= /var/log/keepalived-dns-state .log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE
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4.4、给脚本都加上可执行权限:
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# sudo chmod +x /etc/keepalived/scripts/*.sh |
4.5、启动Keepalived服务
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# service keepalived start |
五、验证
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[root@ip-10-61-100-51 etc] # netstat -ntpl |grep 53
tcp 0 0 10.61.100.50:53 0.0.0.0:* LISTEN 12314 /named tcp 0 0 10.61.100.51:53 0.0.0.0:* LISTEN 12314 /named tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 12314 /named tcp 0 0 127.0.0.1:953 0.0.0.0:* LISTEN 12314 /named tcp 0 0 ::1:953 :::* LISTEN 12314 /named
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[root@ip-10-61-100-52 ~] # vim /etc/keepalived/scripts/dns_stop.sh
[root@ip-10-61-100-52 ~] # netstat -ntpl |grep 53
tcp 0 0 10.61.100.52:53 0.0.0.0:* LISTEN 8220 /named tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 8220 /named tcp 0 0 127.0.0.1:953 0.0.0.0:* LISTEN 8220 /named tcp 0 0 ::1:953 :::* LISTEN 8220 /named
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可以看到VIP已经绑定在Master上,同时可以模拟Master挂掉。VIP会自动漂移到Slave上,带Master恢复后,会再次回到Master上,保证服务可用性。
本文转自 亮公子 51CTO博客,原文链接:http://blog.51cto.com/iyull/1946451