Centos7中KeepAlivedNginx高可用

Centos7中KeepAlived&Nginx高可用

一.部署前规划

角色	操作系统	IP
master	Centos7.8	192.168.56.101
backup	Centos7.8	192.168.56.102

二.keepalived安装

在两台机器上执行安装

yum install -y keepalived

三.master角色配置（192.168.56.101）

/etc/keepalived/keepalived.conf

注意这里：interface enp0s3是对应的网卡名称，如果你的网卡名称不一样，就修改下。

cat > /etc/keepalived/keepalived.conf <<EOF
global_defs {router_id LVS_DEVEL
}vrrp_script chk_nginx {script "/etc/keepalived/scripts/nginx_check.sh"interval 2weight -20
}vrrp_instance VI_1 {state MASTERinterface enp0s3virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_nginx}virtual_ipaddress {192.168.56.140}
}
EOF

编写nginx进程检查的脚本
/etc/keepalived/scripts/nginx_check.sh

##
mkdir /etc/keepalived/scripts/##
cat > /etc/keepalived/scripts/nginx_check.sh <<EOF
#!/bin/bashresult=\`pidof nginx\`
if [ ! -z "\${result}" ];
thenexit 0
elseexit 1
fi
EOF##
chmod +x /etc/keepalived/scripts/nginx_check.sh

四.backup角色配置（192.168.56.102）

/etc/keepalived/keepalived.conf

注意这里：interface enp0s3是对应的网卡名称，如果你的网卡名称不一样，就修改下。

cat > /etc/keepalived/keepalived.conf <<EOF
global_defs {router_id LVS_DEVEL
}vrrp_script chk_nginx {script "/etc/keepalived/scripts/nginx_check.sh"interval 2weight -20
}vrrp_instance VI_1 {state BACKUPinterface enp0s3virtual_router_id 51priority 90advert_int 1authentication {auth_type PASSauth_pass 1111}track_script {chk_nginx}virtual_ipaddress {192.168.56.140}
}
EOF

/etc/keepalived/scripts/nginx_check.sh

##
mkdir /etc/keepalived/scripts/##
cat > /etc/keepalived/scripts/nginx_check.sh <<EOF
#!/bin/bashresult=\`pidof nginx\`
if [ ! -z "\${result}" ];
thenexit 0
elseexit 1
fi
EOF##
chmod +x /etc/keepalived/scripts/nginx_check.sh

五.防火墙开放

注：如果你的防火墙是开放的，一定需要进行vrrp组播的开放，否则因为防火墙不通会两台机器都存在VIP导致keepalived分配vip失败

注意这里：–in-interface enp0s3是对应的网卡名称，如果你的网卡名称不一样，就修改下。

##开启nginx的端口
firewall-cmd --zone=public --add-port=8080/tcp --permanent
firewall-cmd --reload##开启vrrp组播
firewall-cmd --direct --permanent --add-rule ipv4 filter INPUT 0 --in-interface enp0s3 --destination 224.0.0.18 --protocol vrrp -j ACCEPT
firewall-cmd --reload
# 查看规则是否生效
firewall-cmd --permanent --direct --get-all-rules

六.启动keepalived

##设置为系统服务
systemctl enable keepalived##启动
systemctl start keepalived##停止
systemctl stop keepalived##重启
systemctl restart keepalived

七.测试

1.将master和backup的keepalived和nginx都启动,可看到master上存在vip

[root@localhost testuser]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host lovalid_lft forever preferred_lft foreverinet6 ::1/128 scope host valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000link/ether 08:00:27:f7:cc:0c brd ff:ff:ff:ff:ff:ffinet 192.168.56.101/24 brd 192.168.56.255 scope global noprefixroute enp0s3valid_lft forever preferred_lft foreverinet 192.168.56.140/32 scope global enp0s3valid_lft forever preferred_lft foreverinet6 fe80::2603:d512:e7f1:a498/64 scope link noprefixroute valid_lft forever preferred_lft forever

2.而backup上没有，说明当前vip在master上

[root@localhost testuser]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host lovalid_lft forever preferred_lft foreverinet6 ::1/128 scope host valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000link/ether 08:00:27:6c:d4:90 brd ff:ff:ff:ff:ff:ffinet 192.168.56.102/24 brd 192.168.56.255 scope global noprefixroute enp0s3valid_lft forever preferred_lft foreverinet6 fe80::2603:d512:e7f1:a498/64 scope link tentative noprefixroute dadfailed valid_lft forever preferred_lft foreverinet6 fe80::e801:dd62:96e3:cf2b/64 scope link noprefixroute valid_lft forever preferred_lft forever

3.将master上的nginx停止后，vip飘移到backup(192.168.56.102)上，由backup进行服务提供

[root@localhost testuser]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host lovalid_lft forever preferred_lft foreverinet6 ::1/128 scope host valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000link/ether 08:00:27:6c:d4:90 brd ff:ff:ff:ff:ff:ffinet 192.168.56.102/24 brd 192.168.56.255 scope global noprefixroute enp0s3valid_lft forever preferred_lft foreverinet 192.168.56.140/32 scope global enp0s3valid_lft forever preferred_lft foreverinet6 fe80::2603:d512:e7f1:a498/64 scope link tentative noprefixroute dadfailed valid_lft forever preferred_lft foreverinet6 fe80::e801:dd62:96e3:cf2b/64 scope link noprefixroute valid_lft forever preferred_lft forever