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86754tr 发表于 2017-9-11 10:50:01

keepalived服务配置

keepalived
keepalived.service - LVS and VRRP High Availability Monitor

server1(10.71)--server2(10.72)
注意：建议实验环境使用NAT模式来连接，否则客户端可能无法正常访问测试。需要在两台keepalived上配置默认路由，如ip route add default dev eth0.
需要先同步服务器的时间，centos7.3建议使用chrony来同步时间
systemctl restart chronyd
建议指定/etc/hosts文件，对应两台主机的hostname，可以通过hostname通信

安装服务
yum install keepalived
查看配置文件帮助
man keepalived.conf

vrrp单主配置(即一主一备)--server1

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cp keepalived.conf{,.bak}
vi /etc/keepalived.conf
global_defs {
    notification_email {
      root@localhost#接收邮件地址
    }
    notification_email_from keepalived@localhost#发送邮件地址
    smtp_server 127.0.0.1#本地邮件服务
    smtp_connect_timeout 30
    router_id node1#主机名
    vrrp_mcast_group4 224.10.10.18#IPv4的多播地址，默认为224.0.0.18
}
vrrp_instance VI_1 {
    state MASTER#定义该主机的状态，大写MASTER或BACKUP
    interface eth0#定义发送vrrp的接口
    virtual_router_id 14#唯一性，BACKUP需要配置一致
    priority 100#指定优先级
    advert_int 1
    authentication {
      auth_type PASS#简单密码认证
      auth_pass 571f97b2#只支持8位字符长度，可以通过命令获取openssl rand -base64 6
    }
    virtual_ipaddress {
      192.168.10.100/24 dev eth0#配置虚拟IP地址及对应的接口
    }
}




vrrp单主配置--server2
配置同上，需要更改项如下：
router_id node2#主机名
state BACKUP#定义该主机的状态
priority 95#优先级要低于master
注意：密码认证和虚拟IP地址配置需要和master一致

启动服务
systemctl start keepalived
systemctl status keepalived//会显示状态的信息，master主机会显示添加的虚拟IP地址

ip a//可以看到新添加的接口IP

查看发送的组播信息--只有master才会发送组播：
yum install tcpdump
tcpdump -nn -i eth0 host 224.10.10.18

测试停止server1的keepalived服务，虚拟IP地址会自动转移至server2上，如果重新开启server1的服务，则其会重新获取虚拟IP地址，即keepalived默认为抢占模式。
server1: systemctl stop keepalived
server2: ip a

nopreempt：定义工作模式为非抢占模式；
preempt_delay 300：抢占式模式下，节点上线后触发新选举操作的延迟时长；

######################################
vrrp双主配置(即一台服务器同时配置两台虚拟路由)--server1
vi keepalived.conf
在单主配置的基础上，复制上述vrrp_instance VI_1配置段内容，更改如下，（即增加一个虚拟路由器）：

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vrrp_instance VI_2 {#更改名称为VI_2
    state BACKUP#更改为BACKUP
    interface eth0#定义发送vrrp的接口
    virtual_router_id 24#唯一性，需要区别于vrrp1，这里更改为24
    priority 95#指定优先级，需低于master
    advert_int 1
    authentication {
      auth_type PASS#简单密码认证
      auth_pass 5a1fe7b2#更改为新密码
    }
    virtual_ipaddress {
      192.168.10.200/24 dev eth0#更改虚拟IP地址及对应的接口，这里更改为.200
    }
}




vrrp双主配置--server2
配置同上，需要更改项如下：
state MASTER#更改为MASTER
priority 100#优先级
注意：密码认证和虚拟IP地址配置需要和master一致
配置如下：

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vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 24
    priority 100
    advert_int 1
    authentication {
      auth_type PASS
      auth_pass 5a1fe7b2
    }
    virtual_ipaddress {
      192.168.10.200/24 dev eth0
    }
}




测试，停止server1和server2的服务，先开启server1的服务，可以看到两个虚拟IP都在server1上：
server1: systemctl stop keepalived
server1：systemctl start keepalived
server1: ip a
然后开启server2的keepalived服务，可以看到第二个虚拟IP转移到了server2上
server2: systemctl start keepalived
server2: ip a

DNS解析为两条A记录，分别对应两个虚拟IP地址，则可以实现高可用。

##################################
通知脚本的使用方式

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vi notify.sh
#!/bin/bash
contact='root@localhost'
notify() {
    local mailsubject="$(hostname) to be $1, vip floating"
    local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"
    echo "$mailbody" | mail -s "$mailsubject" $contact
}
case $1 in
master)
    notify master
    ;;
backup)
    notify backup
    ;;
fault)
    notify fault
    ;;
*)
    echo "Usage: $(basename $0) {master|backup|fault}"
    exit 1
    ;;
esac




脚本的调用方法，在vrrp_instance配置段中添加以下通知参数，建议放在虚拟IP的配置项之后：

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notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"




测试，启动或重启keepalived服务，然后查看mail信息
systemctl restart keepalived
systemctl status keepalived
ip a
yum install mailx//minimal安装的centos默认没有安装mail程序
mail
或者直接查看邮件文件
more /var/mail/root

#################################
增加两台服务器server3和server4，配置为real server (nginx + lvs)
server1(10.71)----server2(10.72)
          |   
server3(10.73)----server4(10.74)

注意同步时间
systemctl restart chronyd

两台服务器均安装nginx
yum install -y nginx
创建各自的首页文件
server3: echo "RS1-73" > /usr/share/nginx/html/index.html
server4: echo "RS2-74" > /usr/share/nginx/html/index.html
启动两台nginx服务器
systemctl start nginx

rs配置脚本：

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vi setrs.sh
#!/bin/bash
vip=192.168.10.100
mask=255.255.255.255
iface="lo:0"
case $1 in
start)
    echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
    echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
    echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
    echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
    ifconfig $iface $vip netmask $mask broadcast $vip up
    route add -host $vip dev $iface
    echo "The RS Server is Ready!"
    ;;
stop)
    ifconfig $iface down
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
    echo "The RS Server is Canceled!"
    ;;
*)
    echo "Usage: $(basename $0) start|stop"
    exit 1
    ;;
esac




分别在server3和server4上执行此脚本
bash -x setrs.sh start
ifconfig
验证文件参数是否更改
more /proc/sys/net/ipv4/conf/all/arp_ignore
more /proc/sys/net/ipv4/conf/all/arp_announce

#################################
在两台keepalived主机上安装lvs和nginx(用于配置sorry server)
yum install ipvsadm nginx
server1: echo "sorry server 71" > /usr/share/nginx/html/index.html
server2: echo "sorry server 72" > /usr/share/nginx/html/index.html
systemctl start nginx

配置单主keepalived，在server1和server2上配置，需要和之前定义的虚拟IP地址相同为192.168.10.100

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virtual_ipaddress {
    192.168.10.100/24 dev eth0//设置虚拟IP
....
#注释掉之前的双主配置段VI_2
#vrrp_instance VI_2 {...}
virtual_server 192.168.10.100 80 {//地址同上10.100
    delay_loop 6
    lb_algo rr
    lb_kind DR
    protocol TCP
    sorry_server 127.0.0.1 80
    real_server 192.168.10.73 80 {
      weight 1
      HTTP_GET {
            url {
                path /
                status_code 200
            }
      connect_timeout 2
      nb_get_retry 3
      delay_before_retry 1
      }
    }
    real_server 192.168.10.74 80 {
      weight 1
      HTTP_GET {
            url {
                path /
                status_code 200
            }
      connect_timeout 2
      nb_get_retry 3
      delay_before_retry 1
      }
    }
}





重启keepalived服务，并查看虚拟地址，如果无法获取地址，则尝试先stop在start
systemctl restart keepalived
systemctl status keepalived
ip a
ipvsadm -Ln//查看lvs规则，由keepalived自动生成
如果无法查看到后端主机的IP地址，则查看日志信息或messages文件，是否是由于path路径错误导致的，如HTTP status code error to :80 url(/), status_code .
然后确认后端主机上是否存在index.html的首页文件。或者直接配置keepalived.conf指定详细的path路径,如path /index.html.

客户端测试,默认为轮询显示，且停止任意一台keepalived，客户端访问无影响；或者停止一台RS来测试：
for i in {1..10};do curl http://192.168.10.100;done
server2: systemctl stop keepalived
server3: systemctl stop nginx

请求的url验证方式也支持md5验证：
HTTP_GET {
    url {
      path /
      digest ff20ad2481f97b1754ef3e12ecd3a9cc
    }
通过如下命令可以生成该md5码
genhash -s 192.168.10.73 -p 8080 -u /
MD5SUM = 9f9b481ce80b3be16685ce4a39ced5cf

#####################
keepalived调用外部的辅助脚本进行资源监控，并根据监控的结果状态能实现优先动态调整；
分两步：(1) 先定义一个脚本；(2) 调用此脚本；
vrrp_script <SCRIPT_NAME> {
    script ""
    interval INT
    weight -INT
}

track_script {
    SCRIPT_NAME_1
    SCRIPT_NAME_2
    ...
}

例如：

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vrrp_script chk_down {
    script "[ -f /etc/keepalived/down ] && exit 1 || exit 0"
    interval 1
    weight -6
}
vrrp_script chk_nginx {
    script "killall -0 nginx && exit 0 || exit 1"
    interval 1
    weight -6
    fall 2
    rise 1
}
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 14
    priority 100
    advert_int 1
    authentication {
      auth_type PASS
      auth_pass 571f97b2
    }
    virtual_ipaddress {
      192.168.10.100/16 dev eth0
    }
    track_script {
      chk_down
      chk_nginx
    }
}




测试并查看信息提示IP地址已移除
touch /etc/keepalived/down
tail -f /var/log/messages
ip a

#########################
开机启动服务
systemctl enable ipvsadm
systemctl enable httpd
systemctl enable keepalived

单主配置实例：

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more keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
    root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
}
vrrp_script chk_down {
    script "[ -f /etc/keepalived/down ] && exit 1 || exit 0"
    interval 1
    weight -6
}
vrrp_instance VI_1 {
    state MASTER
    interface eth1
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
      auth_type PASS
      auth_pass 1111
    }
    virtual_ipaddress {
      192.168.80.100
    }
    track_script {
      chk_down
    }
}
virtual_server 192.168.80.100 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    nat_mask 255.255.255.0
    protocol TCP
    sorry_server 127.0.0.1 80
    real_server 192.168.80.165 80 {
      weight 1
      HTTP_GET {
            url {
            path /
                status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
      }
    }
    real_server 192.168.80.166 80 {
      weight 1
      HTTP_GET {
            url {
            path /
                status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
      }
    }
}




#########################
配置nginx+keepalived来提供高可用前端代理
环境：
websrv1:192.168.80.165
websrv2:192.168.80.166
webshareIP:192.168.80.100
ng-keep-1:192.168.80.151
ng-keep-2:192.168.80.162

代理服务器ng-keep-1的配置

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vi /etc/nginx/conf.d/nginx.conf
upstream proxy {
    server 192.168.80.165;
    server 192.168.80.166;
    server 127.0.0.1 backup;   //backup表示sorry server
}
server {
    listen 80;
    server_name 192.168.80.100;
    location / {
      proxy_pass http://proxy;
    }
}





配置sorry server测试页
echo "Sorry from nginx-1-151" > /usr/share/nginx/html/index.html
echo "Sorry from nginx-2-162" > /usr/share/nginx/html/index.html

keepalived的配置只需要vrrp_instance配置段，virtual_server,real_server是lvs的配置，nginx用不到，可以删除或注释掉。

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vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
    root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
}
vrrp_script chk_down {
    script "[ -f /etc/keepalived/down ] && exit 1 || exit 0"
    interval 1
    weight -6
}
vrrp_instance VI_1 {
    state MASTER
    interface eth1
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
      auth_type PASS
      auth_pass 1111
    }
    virtual_ipaddress {
      192.168.80.100
    }
    track_script {
      chk_down
    }
}




重启服务ng-keep-1
systemctl restart nginx
systemctl restart keepalived
测试关闭webserver
service httpd stop

客户端测试：
for i in {1..100};do curl 192.168.80.100;sleep 0.5;done

查看完整版本: keepalived服务配置