Keepalived实现高可用

Keepalived实现高可用

参考文档：

1. keepaliveduser guide：http://www.keepalived.org/pdf/UserGuide.pdf

2. 安装文档：源码解压包中的INSTALL文档

本文涉及keepalived的安装，简单配置，为haproxy做高可用。

一．环境准备

1. 操作系统

CentOS-7-x86_64-Everything-1511

2. Keepalived版本

截至2017-03-22，keepalived版本是1.3.5:

http://www.keepalived.org/software/keepalived-1.3.5.tar.gz

3. 拓扑图

1) 采用VMware ESXi虚拟出的2台服务器node1/2，前端访问地址10.11.4.151/152，后端地址192.168.4.151/2；

2) Web1服务器为采用docker技术生成的1台服务器，已安装并启动nginx与php服务，ip地址192.168.4.171；

3) Web2/3同Web1服务器，ip地址192.168.4.172/173；

4) 计划在node1/2两台服务器上部署keepalive&haproxy，利用keepalived虚拟出vip：10.11.4.150做高可用；

5) Haproxy相关配置请参考：http://blog.chinaunix.net/uid-26168435-id-5761429.html，调整后将静态网页指向web1/2服务器的index.html，将动态网页指向web1/2服务器的index.php，其他指向web3服务器；

6) 以web1为例，设置测试页面，以方便后续查看验证结果。

二．Keepalived安装配置

以下流程均在node1节点完成，node2节点请参考node1做适当修改。

1. 依赖软件

1. [root@elk-node1 ~]# yum install openssl-devel libnl3-devel ipset-devel iptables-devel libnfnetlink-devel popt popt-static popt-devel gcc kernel-headers kernel-devel net-snmp-devel -y

#升级或者安装相关软件，不是必需都安装一次，但一般libnl3-devel ipset-develiptables-devel libnfnetlink-devel popt popt-static popt-devel等并没有预安装到系统中，net-snmp-devel是需要开启相关功能才需要。

2. 下载

1. [root@elk-node1 ~]# cd /usr/local/src/
   
2. [root@elk-node1 src]#wget http://www.keepalived.org/software/keepalived-1.3.5.tar.gz

3. 编译安装

1. [root@elk-node1 src]# tar -zxvf keepalived-1.3.5.tar.gz
   
2. [root@elk-node1 src]# cd keepalived-1.3.5
   
3. [root@elk-node1 keepalived-1.3.5]# ./configure --prefix=/usr/local/keepalived
   
4. [root@elk-node1 keepalived-1.3.5]# make
   
5. [root@elk-node1 keepalived-1.3.5]# make install

#编译前可通过”./configure --help”查看相关编译参数；

#此编译未带“--with-kernel-dir”参数，一般认为采用”--with-kernel-dir=/usr/src/kernels/(version)”指定到内核效果更好，可能本人环境比较简单，实际使用后并没有明显的问题；这里未指定是因为centos7在编译使用参数之后找不到”linux/netlink.h”头文件，即使在相应目录下能找到相应头文件，搜了一下也没有找到对应的解决方案。

4. 配置开机启动

1) 启动相关命令

1. [root@elk-node1 ~]# cd /usr/local/keepalived/
   
2. [root@elk-node1 keepalived]# ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
   
3. [root@elk-node1 keepalived]# ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/

#软链接。

2) 配置文件

1. [root@elk-node1 keepalived]# mkdir -p /etc/keepalived
   
2. [root@elk-node1 keepalived]# ln -s /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

#软链接。

3) 开机启动

1. [root@elk-node1 keepalived]# touch /etc/rc.d/init.d/keepalived
   
2. [root@elk-node1 keepalived]# chmod +x /etc/rc.d/init.d/keepalived
   
3. [root@elk-node1 keepalived]# vim /etc/rc.d/init.d/keepalived
   
4. #!/bin/sh
   
5. #
   
6. # keepalived High Availability monitor built upon LVS and VRRP
   
7. #
   
8. # chkconfig: - 86 14
   
9. # description: Robust keepalive facility to the Linux Virtual Server project \
   
10. # with multilayer TCP/IP stack checks.
    
11. ### BEGIN INIT INFO
    
12. # Provides: keepalived
    
13. # Required-Start: $local_fs $network $named $syslog
    
14. # Required-Stop: $local_fs $network $named $syslog
    
15. # Should-Start: smtpdaemon httpd
    
16. # Should-Stop: smtpdaemon httpd
    
17. # Default-Start:
    
18. # Default-Stop: 0 1 2 3 4 5 6
    
19. # Short-Description: High Availability monitor built upon LVS and VRRP
    
20. # Description: Robust keepalive facility to the Linux Virtual Server
    
21. # project with multilayer TCP/IP stack checks.
    
22. ### END INIT INFO
    
23. # Source function library.
    
24. . /etc/rc.d/init.d/functions
    
25. exec="/usr/sbin/keepalived"
    
26. prog="keepalived"
    
27. config="/etc/keepalived/keepalived.conf"
    
28. [ -e /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog
    
29. lockfile=/var/lock/subsys/keepalived
    
30. start() {
    
31. [ -x $exec ] || exit 5
    
32. [ -e $config ] || exit 6
    
33. echo -n $"Starting $prog: "
    
34. daemon $exec $KEEPALIVED_OPTIONS
    
35. retval=$?
    
36. echo
    
37. [ $retval -eq 0 ] && touch $lockfile
    
38. return $retval
    
39. }
    
40. stop() {
    
41. echo -n $"Stopping $prog: "
    
42. killproc $prog
    
43. retval=$?
    
44. echo
    
45. [ $retval -eq 0 ] && rm -f $lockfile
    
46. return $retval
    
47. }
    
48. restart() {
    
49. stop
    
50. start
    
51. }
    
52. reload() {
    
53. echo -n $"Reloading $prog: "
    
54. killproc $prog -1
    
55. retval=$?
    
56. echo
    
57. return $retval
    
58. }
    
59. force_reload() {
    
60. restart
    
61. }
    
62. rh_status() {
    
63. status $prog
    
64. }
    
65. rh_status_q() {
    
66. rh_status &>/dev/null
    
67. }
    
68. case "$1" in
    
69. start)
    
70. rh_status_q && exit 0
    
71. $1