你需要了解的高可用方案之使用keepalived搭建双机热备一览

　　

             在之前一篇使用nginx搭建高可用的解决方案的时候，很多同学会问，如果nginx挂掉怎么办，比如下面这张图：

            你可以清楚的看到，如果192.168.2.100这台机器挂掉了，那么整个集群就下线了，这个问题该怎么解决呢？？？ 简单的想想确实不大好处理，因为你

的webBrowser总得要访问一个ip地址，对吧。。这个问题怎么破呢？

 

一：问题分析

　　如果你有一些网络底子的话，就会明白，你给一个不在本网段的机器发送请求的话，这个请求会先经过你的网关IP，然后通过网关IP传给对方的网关IP，然

后网关IP会将请求转给它所在局域网的主机，当然我的网关IP和对方的网关IP之间可能有很多跳的路由地址，大概的流程就是下面这样：

如果你不信的话，可以用tracert 看看你到www.ctrip.com的路由总过程。

从上图中可以看到，从我当前主机到ctrip.com一共有20跳，第一条是192.168.2.1，这个就是我的路由器IP，也就是我的网关IP。

 

二：虚拟路由冗余协议

　　好了，说了这么多有什么用呢？其实大家仔细观察这张图，你会想我能不能在网关IP上做一些手脚呢？ 可喜的是如今的路由器基本上都支持一个叫做

VRRP（虚拟路由冗余协议），这一协议的作用你可以理解成把网关IP虚拟化成一个网关IP集群，就好像兽族剑圣的镜像技能，这里面有master，也有slave，

然后局域网内的主机设置的都是虚拟的masterIP（VIP），刚好keepealived就是一个实现VRRP的一款应用程序，你需要，我专业，大家就这样走到一块了。

 

三：keepalived搭建一览

1. 下载：从官网上找到当前最新的版本1.4.2。http://www.keepalived.org/software/keepalived-1.4.2.tar.gz。

     配置机器： 192.168.23.156 【centos】

　　　　          192.168.23.157 【centos】

1 [root@localhost app]# wget http://www.keepalived.org/software/keepalived-1.4.2.tar.gz
2 --2018-03-10 04:04:06--  http://www.keepalived.org/software/keepalived-1.4.2.tar.gz
3 Resolving www.keepalived.org (www.keepalived.org)... 37.59.63.157, 2001:41d0:8:7a9d::1
4 Connecting to www.keepalived.org (www.keepalived.org)|37.59.63.157|:80... connected.
5 HTTP request sent, awaiting response... 200 OK
6 Length: 738096 (721K) [application/x-gzip]
7 Saving to: ‘keepalived-1.4.2.tar.gz’
8 
9 100%[==================================================================>] 738,096     5.24KB/s   in 4m 44s 

 

2. 然后把相关依赖装起来：yum install -y openssl openssl-devel。

 1 [root@localhost app]# yum install -y openssl openssl-devel
 2 Loaded plugins: fastestmirror, langpacks
 3 Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
 4 14: curl#52 - "Empty reply from server"
 5 base                                                                                 | 3.6 kB  00:00:00     
 6 epel/x86_64/metalink                                                                 | 7.8 kB  00:00:00     
 7 Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=stock error was
 8 14: curl#52 - "Empty reply from server"
 9 extras                                                                               | 3.4 kB  00:00:00     
10 updates                                                                              | 3.4 kB  00:00:00     
11 updates/7/x86_64/primary_db                                                          | 6.9 MB  00:01:10  

 

3. 接下来继续解压，最后安装三板斧： ./configure --prefix=/usr/app/keepalived && make && make install。

[root@localhost app]# tar -zxvf keepalived-1.4.2.tar.gz
[root@localhost app]# ls
keepalived-1.4.2  keepalived-1.4.2.tar.gz
[root@localhost app]# cd keepalived-1.4.2
[root@localhost keepalived-1.4.2]# ls
aclocal.m4  bin_install  configure     COPYING  genhash     keepalived          Makefile.am  README.md
ar-lib      ChangeLog    configure.ac  depcomp  INSTALL     keepalived.spec.in  Makefile.in  snap
AUTHOR      compile      CONTRIBUTORS  doc      install-sh  lib                 missing      TODO
[root@localhost keepalived-1.4.2]#

[root@localhost keepalived-1.4.2]# ./configure --prefix=/usr/app/keepalived && make && make install

 

安装好了之后，你就会看到如下的内容，那就恭喜你，安装成功了。

Keepalived configuration
------------------------
Keepalived version       : 1.4.2
Compiler                 : gcc
Preprocessor flags       : 
Compiler flags           : -Wall -Wunused -Wstrict-prototypes -Wextra -g -O2 -fPIE -D_GNU_SOURCE
Linker flags             : -pie
Extra Lib                :  -lcrypto  -lssl 
Use IPVS Framework       : Yes
IPVS use libnl           : No
IPVS syncd attributes    : No
IPVS 64 bit stats        : No
fwmark socket support    : Yes
Use VRRP Framework       : Yes
Use VRRP VMAC            : Yes
Use VRRP authentication  : Yes
With ip rules/routes     : Yes
SNMP vrrp support        : No
SNMP checker support     : No
SNMP RFCv2 support       : No
SNMP RFCv3 support       : No
DBUS support             : No
SHA1 support             : No
Use Debug flags          : No
smtp-alert debugging     : No
Use Json output          : No
Stacktrace support       : No
Memory alloc check       : No
libnl version            : None
Use IPv4 devconf         : No
Use libiptc              : No
Use libipset             : No
init type                : systemd
Build genhash            : Yes
Build documentation      : No

 

4. 安装好了之后，在/usr/app/keepalived/etc/keepalived目录下有一个keepalived.conf文件，现在你要做的事情就是

    将它copy到/etc/keepalived文件夹下就可以了。

1 [root@localhost keepalived]# ls
2 keepalived.conf  samples
3 [root@localhost keepalived]# pwd
4 /usr/app/keepalived/etc/keepalived
5 [root@localhost keepalived]# mkdir -p /etc/keepalived
6 [root@localhost keepalived]# cp ./keepalived.conf /etc/keepalived/keepalived.conf

 

5. 接下来我们改一下配置文件。

   在192.168.23.156机器中的配置文件，修改如下：

【原来】

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.200.16
        192.168.200.17
        192.168.200.18
    }
}

 

【修改】

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id NodeA
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.2.200
    }
}

其中要注意的就是：

　　《1》priority 150

　　　　 节点的优先级，master要比slave高。

　　《2》interface ens33

　　　　 ens33大家可以通过ipconfig查看一下自己的网卡。

[root@localhost ~]# ifconfig
br-11757db6abf5: flags=4099  mtu 1500
        inet 172.22.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:c2:e0:52:10  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-875e3c64ec79: flags=4099  mtu 1500
        inet 172.23.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:4e:43:5b:a0  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-904f2c62861e: flags=4099  mtu 1500
        inet 172.19.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:6d:80:36:58  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-b0028a425959: flags=4099  mtu 1500
        inet 172.21.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:68:51:95:99  txqueuelen 0  (Ethernet)
        RX packets 18  bytes 1458 (1.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 41  bytes 3920 (3.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-c4a09a75fc67: flags=4099  mtu 1500
        inet 172.18.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:92:f9:2d:65  txqueuelen 0  (Ethernet)
        RX packets 4  bytes 340 (340.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4  bytes 340 (340.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br-f0fb207788a0: flags=4163  mtu 1500
        inet 172.20.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        inet6 fe80::42:86ff:fe1e:c970  prefixlen 64  scopeid 0x20
        ether 02:42:86:1e:c9:70  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

docker0: flags=4099  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 0.0.0.0
        ether 02:42:8f:8c:a9:a7  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33: flags=4163  mtu 1500
        inet 192.168.23.157  netmask 255.255.255.0  broadcast 192.168.23.255
        inet6 fe80::20c:29ff:fe54:4f5a  prefixlen 64  scopeid 0x20
        ether 00:0c:29:54:4f:5a  txqueuelen 1000  (Ethernet)
        RX packets 10899  bytes 11349012 (10.8 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5575  bytes 599717 (585.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 0  (Local Loopback)
        RX packets 4  bytes 340 (340.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4  bytes 340 (340.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

veth4d72ad4: flags=4163  mtu 1500
        inet6 fe80::d4fb:fcff:feeb:cd7c  prefixlen 64  scopeid 0x20
        ether d6:fb:fc:eb:cd:7c  txqueuelen 0  (Ethernet)
        RX packets 16  bytes 1248 (1.2 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 43  bytes 4130 (4.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

vethe634b1c: flags=4163  mtu 1500
        inet6 fe80::e0c6:88ff:fe1c:f4a1  prefixlen 64  scopeid 0x20
        ether e2:c6:88:1c:f4:a1  txqueuelen 0  (Ethernet)
        RX packets 18  bytes 1458 (1.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 41  bytes 3920 (3.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 00:00:00:00:00:00  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@localhost ~]# 

 

    《3》virtual_ipaddress 192.168.23.200

            设置好虚拟IP（VIP）为：192.168.23.200

同样的道理，在192.168.23.157设置如下：

global_defs {
   notification_email {
     [email protected]
     [email protected]
     [email protected]
   } 
   notification_email_from [email protected]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id NodeB
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}  

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }   
    virtual_ipaddress {
        192.168.23.200
    }   
}

 

7. 接下来就可以启动keepalived了。

[root@localhost sbin]# ./keepalived -D
[root@localhost sbin]# ps -ef | grep keepalived
root       4661      1  0 05:41 ?        00:00:00 ./keepalived -D
root       4662   4661  0 05:41 ?        00:00:00 ./keepalived -D
root       4663   4661  0 05:41 ?        00:00:00 ./keepalived -D
root       4673   4300  0 05:41 pts/0    00:00:00 grep --color=auto keepalived

 

五：检测

1. 通过ip a  看看当前ens33网卡上是否绑定了192.168.23.200虚拟IP。

 

2. 然后通过arp -a 查看当前的vip映射到的物理(mac)地址，可以看到当前的vip映射到的是192.168.23.156上面。

C:\Users\hxc>arp -a

接口: 192.168.23.1 --- 0x6
  Internet 地址         物理地址              类型
  192.168.23.156        00-0c-29-75-7e-20     动态
  192.168.23.157        00-0c-29-54-4f-5a     动态
  192.168.23.200        00-0c-29-75-7e-20     动态
  192.168.23.255        ff-ff-ff-ff-ff-ff     静态
  224.0.0.22            01-00-5e-00-00-16     静态
  224.0.0.251           01-00-5e-00-00-fb     静态
  224.0.0.252           01-00-5e-00-00-fc     静态
  239.11.20.1           01-00-5e-0b-14-01     静态
  239.255.255.250       01-00-5e-7f-ff-fa     静态
  255.255.255.255       ff-ff-ff-ff-ff-ff     静态

 

  3. 然后我们把156这台机器关闭了，可以看到当前的vip已经漂移到了157这台机器上了。

C:\Users\hxc>arp -a

接口: 192.168.23.1 --- 0x6
  Internet 地址         物理地址              类型
  192.168.23.156        00-0c-29-75-7e-20     动态
  192.168.23.157        00-0c-29-54-4f-5a     动态
  192.168.23.200        00-0c-29-54-4f-5a     动态
  192.168.23.255        ff-ff-ff-ff-ff-ff     静态
  224.0.0.22            01-00-5e-00-00-16     静态
  224.0.0.251           01-00-5e-00-00-fb     静态
  224.0.0.252           01-00-5e-00-00-fc     静态
  239.11.20.1           01-00-5e-0b-14-01     静态
  239.255.255.250       01-00-5e-7f-ff-fa     静态
  255.255.255.255       ff-ff-ff-ff-ff-ff     静态

   

      好了，这个就是本篇所说的所有内容，希望对您有帮助。