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:

你需要了解的高可用方案之使用keepalived搭建双机热备一览_第1张图片
Java

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:

你需要了解的高可用方案之使用keepalived搭建双机热备一览_第2张图片
Java

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

你需要了解的高可用方案之使用keepalived搭建双机热备一览_第3张图片
Java

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】

[root@localhost app]# wget http://www.keepalived.org/software/keepalived-1.4.2.tar.gz

--2018-03-10 04:04:06-- http://www.keepalived.org/software/keepalived-1.4.2.tar.gz

Resolving www.keepalived.org (www.keepalived.org)... 37.59.63.157, 2001:41d0:8:7a9d::1

Connecting to www.keepalived.org (www.keepalived.org)|37.59.63.157|:80... connected.

HTTP request sent, awaiting response... 200 OK

Length: 738096 (721K) [application/x-gzip]

Saving to: ‘keepalived-1.4.2.tar.gz’

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。

[root@localhost app]# yum install -y openssl openssl-devel

Loaded plugins: fastestmirror, langpacks

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was

14: curl#52 - "Empty reply from server"

base | 3.6 kB 00:00:00

epel/x86_64/metalink | 7.8 kB 00:00:00

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=stock error was

14: curl#52 - "Empty reply from server"

extras | 3.4 kB 00:00:00

updates | 3.4 kB 00:00:00

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 ~]# ifconfigbr-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=4163mtu 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 0x20ether 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=4163mtu 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=73mtu 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=4163mtu 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=4163mtu 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      46611005:41?00:00:00./keepalived -D

root      46624661005:41?00:00:00./keepalived -D

root      46634661005:41?00:00:00./keepalived -D

root      46734300005:41pts/000:00:00grep --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。

你需要了解的高可用方案之使用keepalived搭建双机热备一览_第4张图片
Java

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:Usershxc>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:Usershxc>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。

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