微服务实战系列（十）-网关高可用之中间件Keepalived
1.场景描述
因为要做网关的高可用，用到了keepalived+nginx，来保证nginx的高可用，如下图：
安装了keepavlived，走了一些弯路，记录下吧，nginx的安装就不多说了，自己博客已经介绍了好几篇了。
2. 解决方案
2.1 安装keepalived
2.1.1 安装相关依赖包
[root@t-ruanjianlaowang ~]# yum install -y libnl*[root@t-ruanjianlaowang ~]# yum install -y libnfnetlink-devel zlib zlib-devel gcc gcc-c++ openssl openssl-devel openssh
假如连不了，网上也有这些包的下载，下载后tar解压也行。
2.1.2 下载并安装keepalived
我们使用的版本：keepalived-2.0.18.tar.gz，993k
tar -zxvf keepalived-2.0.18.tar.gzcd keepalived-2.0.18/./configure --prefix=/usr/local/keepalivedmakemake install
2.1.3 添加keepavlived为系统服务
[root@t-ruanjianlaowang ~]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/keepalived[root@t-ruanjianlaowang ~]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/keepalived[root@t-ruanjianlaowang ~]# cp /root/tools/keepalived-2.0.18/keepalived/etc/init.d/keepalived /etc/init.d/keepalived#/etc/keepalived下好像有了keepalived文件夹，有了就不用mkdir了，软件老王[root@t-ruanjianlaowang ~]# mkdir /etc/keepalived[root@t-ruanjianlaowang ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
2.1.4 设置开机启动
# 设置开机启动[root@t-ruanjianlaowang ~]# chkconfig keepalived on[root@t-ruanjianlaowang ~]# service keepalived start|stop|restart
到这里仅仅是keepalived安装完成，接下来还要根据项目项目配置keepalived.conf信息。
2.2 配置文件修改
2.2.1 master的conf配置文件
vi cd /etc/keepalived/keepalived.conf!Configuration File for keepalivedglobal_defs {router_id RUANJIANLAOWANG_MASTER}vrrp_script chk_nginx {script "/etc/keepalived/nginx_check.sh"interval 2weight -20}vrrp_instance VI_1 {state MASTERinterface ens666 #这里必须非常注意，软件老王刚开始没太注意，这里是你的网卡名称virtual_router_id 81 #这个会在backup机器上用到priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_nginx}virtual_ipaddress {10.192.168.21}}
2.2.2 还有个检查nginx是否挂掉的sh，也上传下
vi nginx_check.sh#!/bin/bashcounter=$(ps -C nginx --no-heading|wc -l)if [ "${counter}" = "0" ]; then/usr/sbin/nginxsleep 2counter=$(ps -C nginx --no-heading|wc -l)if [ "${counter}" = "0" ]; then/etc/init.d/keepalived stopfifi
2.2.3 backup机器上conf文件
/bin/bash: Configuration: command not foundbal_defs {router_id RUANJIANLAOWANG2}vrrp_script chk_nginx {script "/etc/keepalived/nginx_check.sh" ## 检测 nginx 状态的脚本路径interval 2 ## 检测时间间隔weight -20 ## 如果条件成立，权重-20}vrrp_instance VI_1 {state BACKUPinterface ens168virtual_router_id 81priority 90advert_int 1authentication {auth_type PASSauth_pass 111track_script {chk_nginx ## 执行 Nginx 监控的服务，软件老王}virtual_ipaddress {10.192.168.21}}
这里记着也把检查nginx的sh文件上传上，跟master上的一样。
2.3 启动
（1）配置完成后开始启动
[root@t-ruanjianlaowang ~]# service keepalived start（2）启动过程中，打开日志看一下（刚开始可能会有问题，看下日志啥都明白了）
[root@t-ruanjianlaowang ~]# tail -f /var/log/messages（3）假如启动不了，可以尝试以下方式。
[root@t-ruanjianlaowang ~]# systemctl daemon-reload#上面试过后，不行再重新注册服务[root@t-ruanjianlaowang ~]#chkconfig --del keepalived[root@t-ruanjianlaowang ~]# cd /usr/lib/systemd/system/[root@t-ruanjianlaowang ~]#rm -rf keepalived.service[root@t-ruanjianlaowang ~]# chkconfig --add keepalived
2.4 验证
[root@t-ruanjianlaowang ~]#ip addr show ens666[root@t-ruanjianlaowang ~]#ip addr show ens168ens666、ens168为网卡名称假如绑定成功，软件老王机器里显示的信息里面会有：10.192.168.21的显示
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