nginx+keepalived 高可用方案
准备工作
- 192.168.157.11
- 192.168.157.12
安装nginx
-
跟新yum源文件
rpm -ivh http://nginx.org/packages/centos/7/noarch/RPMS/nginx-release-centos-7-0.el7.ngx.noarch.rpm
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo -
安装nginx
yum -y install nginx
-
操作命令
systemctl start nginx; # 启动nginx
systemctl stop nginx; # 停止nginx
什么是高可用
- 高可用HA(High Availability)是分布式系统架构设计中必须考虑的因素之一,它通常是指,通过设计减少系统不能提供服务的时间。如果一个系统能够一直提供服务,那么这个可用性则是百分之百,但是天有不测风云。所以我们只能尽可能的去减少服务的故障。
解决的问题
-
在生产环境上很多时候是以
Nginx
做反向代理对外提供服务,但是一天Nginx难免遇见故障,如:服务器宕机。当Nginx
宕机那么所有对外提供的接口都将导致无法访问。虽然我们无法保证服务器百分之百可用,但是也得想办法避免这种悲剧,今天我们使用
keepalived
来实现Nginx
的高可用
双机热备方案
- 这种方案是国内企业中最为普遍的一种高可用方案,双机热备其实就是指一台服务器在提供服务,另一台为某服务的备用状态,当一台服务器不可用另外一台就会顶替上去。
keepalived是什么?
Keepalived
软件起初是专为LVS
负载均衡软件设计的,用来管理并监控LVS集群系统中各个服务节点的状态,后来又加入了可以实现高可用的VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议)
功能。因此,Keepalived
除了能够管理LVS软件外,还可以作为其他服务(例如:Nginx、Haproxy、MySQL等)
的高可用解决方案软件
安装keepalived
-
yum方式安装,该方式会自动安装依赖:
yum -y install keepalived
-
yum 安装产生的配置文件在/etc/keepalived/keepalive.conf
-
编译安装
yum install -y openssl-devel
cd /usr/local/src
wget http://www.keepalived.org/software/keepalived-2.0.16.tar.gz
tar zxf keepalived-2.0.16.tar.gz
cd keepalived-2.0.16
./configrue --prefix=/usr/local/keepalived
make
make install clean
cp /usr/local/src/keepalived-2.0.16/keepalived/etc/init.d/keepalived /etc/init.d/keepalived
chmod +x /etc/init.d/keepalived
echo "/etc/init.d/keepalived start " >> /etc/rc.local
mkdir /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/keepalived/etc/sbin/keepalived /usr/sbin -
启动命令
service keepalived start # 启动
service keeplived stop# 停止
systemctl start keeplived #启动(与1相同)
实现过程
-
修改192.168.157.11中的keepalived, 编辑/etc/keepalived/keepalive.conf (MASTER为主)
#检测脚本nginx
vrrp_script chk_http_port {
script "/etc/keepalived/script/check_nginx_pid.sh" #心跳执行的脚本,检测nginx是否启动
interval 2 #(检测脚本执行的间隔,单位是秒)
weight 2 #权重
}#检测tomcat的
vrrp_script chk_tomcat {
script "etc/keepalived/script/tomcat.sh"
interval 2
weight 2 #权重
}#vrrp 实例定义部分
vrrp_instance VI_1 {
state MASTER # 指定keepalived的角色,MASTER为主,BACKUP为备
interface ens33 # 当前进行vrrp通讯的网络接口卡(当前centos的网卡) 用ifconfig查看你具体的网卡
virtual_router_id 51 # 虚拟路由编号,主从要一直
priority 150 # 优先级,数值越大,获取处理请求的优先级越高
advert_int 1 # 检查间隔,默认为1s(vrrp组播周期秒数)
#授权访问
authentication {
auth_type PASS #设置验证类型和密码,MASTER和BACKUP必须使用相同的密码才能正常通信
auth_pass 1111
}
track_script {
chk_http_port # nginx脚本
chk_tomcat# tomcat脚本
}
virtual_ipaddress {
192.168.157.130/24 # 定义虚拟ip(VIP),可多设,每行一个
}
}
-
virtual_ipaddress
里面可以配置vip,在线上通过vip来访问服务。interface
需要根据服务器网卡进行设置通常查看方式
ip addrauthentication
配置授权访问后备机也需要相同配置
-
修改192.168.157.12中的keepalived配置文件, (BACKUP为备用)
#检测脚本nginx
vrrp_script chk_http_port {
script "/etc/keepalived/script/check_nginx_pid.sh" #心跳执行的脚本,检测nginx是否启动
interval 2 #(检测脚本执行的间隔,单位是秒)
weight 2 #权重
}#检测tomcat的
vrrp_script chk_tomcat {
script "etc/keepalived/script/tomcat.sh"
interval 2
weight 2 #权重
}#vrrp 实例定义部分
vrrp_instance VI_1 {
state BACKUP # 指定keepalived的角色,MASTER为主,BACKUP为备
interface ens33 # 当前进行vrrp通讯的网络接口卡(当前centos的网卡) 用ifconfig查看你具体的网卡
virtual_router_id 51 # 虚拟路由编号,主从要一直
priority 140 # 优先级,数值越大,获取处理请求的优先级越高
advert_int 1 # 检查间隔,默认为1s(vrrp组播周期秒数)
#授权访问
authentication {
auth_type PASS #设置验证类型和密码,MASTER和BACKUP必须使用相同的密码才能正常通信
auth_pass 1111
}
track_script {
chk_http_port # nginx脚本
chk_tomcat# tomcat脚本
}
virtual_ipaddress {
192.168.157.130/24 # 定义虚拟ip(VIP),可多设,每行一个
}
} -
检测脚本:
#!/bin/bash
#检测nginx是否启动了
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ];then #如果nginx没有启动就启动nginx
systemctl start nginx #重启nginx
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then #nginx重启失败,则停掉keepalived服务,进行VIP转移
killall keepalived
fi
fitomcat脚本
#!/bin/bash
JAVA_PROCESS=`ps -C java --no-heading| wc -l`
if [ $JAVA_PROCESS -eq 0 ];then
echo "tomcat is stop"
sleep 2
if [ `ps -C java --no-heading| wc -l` -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi -
脚本授权
chmod 775 check_nginx_pid.shchmod 775 tomcat.sh
验证
-
启动157.11和157.12中的nginx和keepalived
systemctl start nginx; #启动
service keepalived start # 启动 -
访问网址http://192.168.157.130 ,正常查看,
ip a # 进行验证是否存在虚拟主机
-
模拟宕机, 关闭157.11的服务器 reboot 关机
-
再次访问网址, http://192.168.157.130,正常查看
-
查看ip 正常, 则配置成功
ip a
修改配置文件
-
配置文件路径/etc/sysconfig/keepalived
KEEPALIVED_OPTIONS=”-D -d -S 0”保存退出
-
修改日志文件
vim /etc/rsyslog.conf#### GLOBAL DIRECTIVES ##### Where to place auxiliary files
$WorkDirectory /var/lib/rsyslog# Use default timestamp format
$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat# File syncing capability is disabled by default. This feature is usually not required,
# not useful and an extreme performance hit
#$ActionFileEnableSync on
local0.* /var/log/keepalived.log #添加该句代码, 注意不要注释 -
重启rsyslog服务和keepalived
service rsyslog restart
service keepalived restart -
查看日志信息
tail /var/log/keepalived.log
报错
-
默认日志存放在系统日志:/var/log/messages下查看报错
-
如果配置日志文件 可以在/var/log/keepalived.log进行查看
-
通过查看日志错误进行修改即可,
其他功能
-
百度搜索keepalived配置文件详解查看
-
线上参考配置
! Configuration File for keepalivedvrrp_instance ka_192_168_128_204 {
state BACKUP
interface eth0
virtual_router_id 204
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 128204
}
virtual_ipaddress {
192.168.128.204/24 brd 192.168.128.255 dev eth0 label eth0:1
}}virtual_server 192.168.128.204 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP real_server 192.168.128.119 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
} real_server 192.168.128.120 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
} real_server 192.168.128.121 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
} real_server 192.168.128.122 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
借鉴博客
- 借鉴博客: http://www.uml.org.cn/zjjs/201808214.asp
- keepalived各个配置项和术语说明:https://blog.csdn.net/wzyzzu/article/details/50787042
- 高并发场景 LVS 安装及高可用实现:https://www.cnblogs.com/clsn/p/7920637.html