集群相关概念简述
HA是High Available缩写，是双机集群系统简称，指高可用性集群，是保证业务连续性的有效解决方案，一般有两个或两个以上的节点，且分为活动节点及备用节点。
1、集群的分类：
LB：负载均衡集群
lvs负载均衡
nginx反向代理
HAProxyHA：
高可用集群
heartbeat
keepalived
redhat5 : cman + rgmanager , conga(WebGUI) --> RHCS（Cluster Suite）集群套件
redhat6 : cman + rgmanager , corosync + pacemaker
redhat7 : corosync + pacemaker
HP：高性能集群
2、系统可用性的计算公式
A=MTBF/(MTBF+MTTR)
A：高可用性，指标：95%, 99%, 99.5%, ...., 99.999%，99.9999%等
MTBF：平均无故障时间
MTTR：平均修复时间
keepalived的概念
keepalived官网http://www.keepalived.org
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。
Keepalived软件主要是通过VRRP协议实现高可用功能的。VRRP是Virtual Router RedundancyProtocol(虚拟路由器冗余协议）的缩写，VRRP出现的目的就是为了解决静态路由单点故障问题的，它能够保证单个主节点宕机时，整个网络可以不间断地运行。
总结，Keepalived 一方面具有配置管理LVS的功能，同时还具有对LVS下面节点进行健康检查的功能，另一方面也可实现系统网络服务的高可用功能。
keepalived的功能
管理LVS负载均衡软件
实现LVS集群节点的健康检查中
作为系统网络服务的高可用性（failover）
Keepalived高可用故障切换转移原理
Keepalived高可用服务对之间的故障切换转移，是通过 VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议）来实现的。
在 Keepalived服务正常工作时，主 Master节点会不断地向备节点发送（多播的方式）心跳消息，用以告诉备Backup节点自己还活看，当主 Master节点发生故障时，就无法发送心跳消息，备节点也就因此无法继续检测到来自主 Master节点的心跳了，于是调用自身的接管程序，接管主Master节点的 IP资源及服务。而当主 Master节点恢复时，备Backup节点又会释放主节点故障时自身接管的IP资源及服务，恢复到原来的备用角色。
Failover：故障切换，即某资源的主节点故障时，将资源转移至其它节点的操作；
Failback：故障移回，即某资源的主节点故障后重新修改上线后，将转移至其它节点的资源重新切回的过程；
VRRP:
VRRP ,全 称 Virtual Router Redundancy Protocol ,中文名为虚拟路由冗余协议 ，VRRP的出现就是为了解决静态路由的单点故障问题，是通过一种竞选机制来将路由的任务交给某台VRRP路由器的。
keepalived的组成
包名： keepalived
程序环境：
主配置文件：/etc/keepalived/keepalived.conf
主程序文件：/usr/sbin/keepalived
Unit File的环境配置文件：/etc/sysconfig/keepalived
配置文件配置简析
全局配置段：
#vim/etc/keepalived/keepalived.conf #各个配置模块的信息详解 global_defs { #全局默认配置，多数都不需要更改 notification_email { #邮件设置 acassen@firewall.loc #当主节点出现故障时发送邮件 failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc #发送邮件地址，
使用意义不大 smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL #路由器标识，信息不是特别关键 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_pmcast_group4 224.0.44.44 #添加组播地址，防止在同一网段的其他机器被多播影响 vrrp_gna_interval 0 vrrp_iptables #可在默认的全局选项中添加此条选项，
防止主节点在重启后生成iptables规则，造成主节点的再次启用失败 }
虚拟路由实例段
vrrp_instance VI_1 { #虚拟IP地址的设置 state MASTER #设置为主节点 interface eth0 #作用哪个物理网卡上 virtual_router_id 51 #路由器编号自定义，0-255之间的数字就可以 priority 100 #优先级的值0-255之间数字越大优先级越高 advert_int 1 #自己的心跳信息；每隔多少秒向外发布依次 authentication { #认证 auth_type PASS #认证方式：密码认证 auth_pass 1111 #输入密码；随意字符和数字最长八位 } virtual_ipaddress { #VIP配置 <IPADDR>/<MASK> brd <IPADDR> dev <STRING> scope <SCOPE> label <LABEL> 192.168.200.17/24 dev eth1 192.168.200.18/24 dev eth2 label eth2:1 } track_interface { #配置要监控的网络接口，一旦接口出现故障，则转为FAULT状态； eth0 eth1 ... } 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； notify_master <STRING>|<QUOTED-STRING>：当前节点成为主节点时触发的脚本； notify_backup <STRING>|<QUOTED-STRING>：当前节点转为备节点时触发的脚本； notify_fault <STRING>|<QUOTED-STRING>：当前节点转为“失败”状态时触发的脚本； notify <STRING>|<QUOTED-STRING>：通用格式的通知触发机制，一个脚本可完成以上三种状态的转换时的通知； }
虚拟服务器配置：
virtual_server IP port | virtual_server fwmark int { delay_loop <INT>：服务轮询的时间间隔； lb_algo rr|wrr|lc|wlc|lblc|sh|dh：定义调度方法； lb_kind NAT|DR|TUN：集群的类型； persistence_timeout <INT>：持久连接时长； protocol TCP：服务协议，仅支持TCP； sorry_server <IPADDR> <PORT>：备用服务器地址； real_server { weight <INT> notify_up <STRING>|<QUOTED-STRING> notify_down <STRING>|<QUOTED-STRING> HTTP_GET|SSL_GET|TCP_CHECK|SMTP_CHECK|MISC_CHECK { ... }：定义当前主机的健康状态检测方法； } HTTP_GET|SSL_GET：应用层检测 HTTP_GET|SSL_GET { url { path <URL_PATH>：定义要监控的URL； status_code <INT>：判断上述检测机制为健康状态的响应码； digest <STRING>：判断上述检测机制为健康状态的响应的内容的校验码； } nb_get_retry <INT>：重试次数； delay_before_retry <INT>：重试之前的延迟时长； connect_ip <IP ADDRESS>：向当前RS的哪个IP地址发起健康状态检测请求 connect_port <PORT>：向当前RS的哪个PORT发起健康状态检测请求 bindto <IP ADDRESS>：发出健康状态检测请求时使用的源地址； bind_port <PORT>：发出健康状态检测请求时使用的源端口； connect_timeout <INTEGER>：连接请求的超时时长； } TCP_CHECK { connect_ip <IP ADDRESS>：向当前RS的哪个IP地址发起健康状态检测请求 connect_port <PORT>：向当前RS的哪个PORT发起健康状态检测请求 bindto <IP ADDRESS>：发出健康状态检测请求时使用的源地址； bind_port <PORT>：发出健康状态检测请求时使用的源端口； connect_timeout <INTEGER>：连接请求的超时时长； } }
脚本定义：
vrrp_script <SCRIPT_NAME> { script "" #定义执行脚本 interval INT #多长时间检测一次 weight -INT #如果脚本的返回值为假，则执行权重减N的操作 rise 2 #检测2次为真，则上线 fall 3 #检测3次为假，则下线 } vrrp_instance VI_1 { track_script { #在虚拟路由实例中调用此脚本 SCRIPT_NAME_1 SCRIPT_NAME_2 ... } }
HTTP_GET|SSL_GET：应用层检测（7层检测）
path <URL_PATH>：定义要监控的URL； status_code <INT>：判断上述检测机制为健康状态的响应码； digest <STRING>：判断上述检测机制为健康状态的响应的内容的校验码； } nb_get_retry <INT>：重试次数； delay_before_retry <INT>：重试之前的延迟时长； connect_ip <IP ADDRESS>：向当前RS的哪个IP地址发起健康状态检测请求 connect_port <PORT>：向当前RS的哪个PORT发起健康状态检测请求 bindto <IP ADDRESS>：发出健康状态检测请求时使用的源地址； bind_port <PORT>：发出健康状态检测请求时使用的源端口； connect_timeout <INTEGER>：连接请求的超时时长；向RS1服务器发送请求对方没有响应，
等待时长。 }
TCP_CHECK { （tcp4层检测）
connect_ip <IP ADDRESS>：向当前RS的哪个IP地址发起健康状态检测请求 connect_port <PORT>：向当前RS的哪个PORT发起健康状态检测请求 bindto <IP ADDRESS>：发出健康状态检测请求时使用的源地址； bind_port <PORT>：发出健康状态检测请求时使用的源端口； connect_timeout <INTEGER>：连接请求的超时时长； }
实验：实现单主配置的示例:(单个的虚拟VRRP IP地址，一个用作主节点，一个作为备用节点）
具体配置信息：（在同一个网路中实现）
实验环境：selinux 和ptables是否关闭;时间是否同步；如果不同步：timedatectl set-timezone Asia/Shanghai可以用此命令设置仅在centos7上有此命令
查看网卡信息：是否有以下信息多播方式（默认都有）
如果没有此条信息：则需要手动开启此选项
ip link set dev ens33 multicast on #开启多播模式 ip link set dev ens33 multicast off #关闭多播模式
1） 在主的机器上：
#yum install keepalived #安装包 #vim /etc/keepalived/keepalived.conf #修改配置文件 global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 95 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.130.200 #自定义虚拟IP地址 } }
2）在从的机器上：
yum install keepalived #安装包 vim /etc/keepalived/keepalived.conf #修改配置文件 global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 } vrrp_instance VI_1 { state BACKUP #状态改为备用模式 interface ens33 virtual_router_id 51 priority 95 #优先级改小一点 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.130.200 } } #systemctl start keepalived #ip a l ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:fd:b3:24 brd ff:ff:ff:ff:ff:ff inet 192.168.130.11/24 brd 192.168.130.255 scope global ens33 valid_lft forever preferred_lft forever inet 192.168.130.200/32 scope global ens33 #配置文件的虚拟IP绑定到从节点上了 valid_lft forever preferred_lft forever inet6 fe80::20c:29ff:fefd:b324/64 scope link
将主节点的服务器开启：systemctl start keepalived 配置的虚拟IP又绑定到了主节点网卡上
由于是抢占模式，当主节点的服务器起来之后，发现自己的优先级高于从节点的服务器，所以将虚拟IP地址又抢占过来了。
多主配置：2个虚拟的VRRP IP地址，共同提供一个服务，分别在主从上加从主
用户自定义的通知脚本：（通过邮件的方式通知此节点现在所处于什么状态）
在实现单主模式下的keepalived的基础上添加的
notify_master <STRING>|<QUOTED-STRING>：当前节点成为主节点时触发的脚本；
notify_backup <STRING>|<QUOTED-STRING>：当前节点转为备节点时触发的脚本；
notify_fault <STRING>|<QUOTED-STRING>：当前节点转为“失败”状态时触发的脚本；
notify <STRING>|<QUOTED-STRING>：通用格式的通知触发机制，一个脚本可完成以上三种状态的转换时的通知；
#cd /etc/keepalived vim 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 #yum install mailx -y #安装mail命令 #chmod +x notify.sh #给脚本添加执行权限
脚本调用方法
#vim /etc/keepalived/keepalived.conf virtual_ipaddress { 192.168.130.200 } } track_interface { ens33 } notify_master “/etc/keepalived/notify.sh master” notify_backup “/etc/keepalived/notify.sh backup” notify_fault “/etc/keepalived/notify.sh fault” #systemctl start keepalived #mail #查看邮件信息，可以看到当前主备节点转换的过程和当前所处的状态信息
目的：：在上述实验中可以发现，自定义的脚本可以执行你所自定义的任务，所以也可以定义其他的脚本来执行用户所定义的要执行的内容。
实验：结合keepalived来实现LVS的高可用
环境：
各节点时间必须同步；
timedatectl set-timezone Asia/Shanghai#centos7上有此命令
确保iptables及selinux的正确配置；
各节点之间可通过主机名互相通信（对KA并非必须），建议使用/etc/hosts文件实现；
确保各节点的用于集群服务的接口支持MULTICAST通信；D类：224-239；
ip link set dev eth0 multicast off | on
1）在主节点LVS机器上配置
~]# yum install keepalied ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { root@localhost #收件人 } notification_email_from keepalived@localhoat #发件人 smtp_server 127.0.0.1 #邮件服务器IP smtp_connect_timeout 30 #连接超时时长 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 #组播地址 vrrp_iptables #禁止keepalived添加iptables规则 } vrrp_instance VI_1 { #定义虚拟路由实例 state MASTER #初始启动为主节点 interface ens33 #IP属于的网卡 virtual_router_id 51 #节点ID priority 100 #优先级 advert_int 1 #每1秒检测一次 authentication { #认证 auth_type PASS #简单认证 auth_pass 1111 #认证密码 } virtual_ipaddress { #vip绑定的网卡 192.168.130.100/24 dev ens33 } } virtual_server 192.168.130.100 80 { #ipvs规则定义 delay_loop 2 #健康检测，2秒 lb_algo rr #调度算法，轮询 lb_kind DR #lvs模型，DR protocol TCP #tcp协议 real_server 192.168.130.7 80 { #real-server配置 weight 1 #权重为1 HTTP_GET { #HTTP协议检测 url { path / #检测主页 status_code 200 #返回值为200为正常 } connect_timeout 2 #超时时长 nb_get_retry 3 #重连次数 delay_before_retry 1 #重连间隔 } } real_server 192.168.130.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } }
~]#yum install ipvsadm #安装实现LVS的包
~]#ip a a 192.168.130.100/24 dev ens33:1 #将VIP地址绑定到LVS本机的DIP上
~]#ip a l #查看VIP是否绑定到本机的网卡上了
~]#systemctl start keepalived #启动服务作为备用模式
~]#ipvsadm -Ln #查看ipvs规则是否生成了
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.130.100:80 rr persistent 50
-> 192.168.130.7:80 Route 1 0 0
-> 192.168.130.10:80 Route 1 0 0
2)在备节点LVS机器上配置
~]# yum install keepalied ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { root@localhost #收件人 } notification_email_from keepalived@localhoat #发件人 smtp_server 127.0.0.1 #邮件服务器IP smtp_connect_timeout 30 #连接超时时长 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 #组播地址 vrrp_iptables #禁止keepalived添加iptables规则 } vrrp_instance VI_1 { #定义虚拟路由实例 state BACKUP #初始启动为备节点 interface ens33 #IP属于的网卡 virtual_router_id 51 #节点ID priority 95 #优先级 advert_int 1 #每1秒检测一次 authentication { #认证 auth_type PASS #简单认证 auth_pass 1111 #认证密码 } virtual_ipaddress { #vip绑定的网卡 192.168.130.100/24 dev ens33 } } virtual_server 192.168.130.100 80 { #ipvs规则定义 delay_loop 2 #健康检测，2秒 lb_algo rr #调度算法，轮询 lb_kind DR #lvs模型，DR protocol TCP #tcp协议 real_server 192.168.130.7 80 { #real-server配置 weight 1 #权重为1 HTTP_GET { #HTTP协议检测 url { path / #检测主页 status_code 200 #返回值为200为正常 } connect_timeout 2 #超时时长 nb_get_retry 3 #重连次数 delay_before_retry 1 #重连间隔 } } real_server 192.168.130.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } }
~]#yum install ipvsadm #安装实现LVS的包 ~]#ip a a 192.168.130.100/24 dev ens33:1 #将VIP地址绑定到LVS本机的DIP上 ~]#ip a l #查看VIP是否绑定到本机的网卡上了 ~]#systemctl start keepalived #启动服务作为备用模式 ~]#ipvsadm -Ln #查看ipvs规则是否生成了 IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.130.100:80 rr persistent 50 -> 192.168.130.7:80 Route 1 0 0 -> 192.168.130.10:80 Route 1 0 0
3)在后台web服务器上的配置RS1
#yum install httpd #安装包 echo test1 > /var/www/html/index.html #创建测试主页面 修改内核配置来防止VIP地址的相互冲突： #echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore #echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore #echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce #echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce # cat /proc/sys/net/ipv4/conf/all/arp_ignore #验证修改的内核参数是否成功 1 # cat /proc/sys/net/ipv4/conf/all/arp_announce #验证修改的内核参数是否成功 2 将VIP地址绑定到本机的回环网卡上： #ip a a 192.168.130.100 dev lo 此种只是临时绑定重启服务就会失效的
4）在后台web服务器上的配置RS2
#yum install httpd #安装包 echo test2 > /var/www/html/index.html #创建测试主页面 修改内核配置来防止VIP地址的相互冲突： #echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore #echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore #echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce #echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce # cat /proc/sys/net/ipv4/conf/all/arp_ignore #验证修改的内核参数是否成功 1 # cat /proc/sys/net/ipv4/conf/all/arp_announce #验证修改的内核参数是否成功 2 将VIP地址绑定到本机的回环网卡上： #ip a a 192.168.130.100/32 dev lo 此种只是临时绑定重启服务就会失效的
5）client端访问
# curl 192.168.130.100 #此IP地址为VIP地址 test2 # curl 192.168.130.100 #此IP地址为VIP地址 test1
可以在后台web服务器上web1/web2：配置脚本 （永久）
#!/bin/bash # vip="192.168.130.100/32" iface="lo" 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 ip addr add $vip label $iface:0 broadcast ${vip%/*} dev $iface ip route add $vip dev $iface ;; stop) ip addr flush dev $iface ip route flush dev $iface 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 "Usage: `basename $0` start | stop" 1>&2 ;; esac
实验：实现nginx的高可用
1 . 在实现keepalived的主备（抢占模式）的基础上
1）在主节点上配置
# vim /etc/keepalived/keepalived.conf sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 vrrp_iptables } vrrp_script chk_nginx { #定义一个小脚本，检测本机的nginx程序，检测到nginx暂停 script "killall -0 nginx && exit 0 || exit 1" interval 1 weight -5 #就把优先级-5；之后就小于备节点的优先级，将抢占虚拟IP fall 2 rise 1 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 虚拟IP 192.168.130.200/24 } track_script { #调用脚本 chk_nginx } } #yum install nginx #装包 #vim /etc/nginx/conf.d/test.conf #创建nginx的配置文件 server { listen 80 default_server; server_name www.a.com; root /usr/share/nginx/html; location / { proxy_pass http://www; } } #vim /etc/nginx/nginx.conf http { #在http上添加 upstream www { server 192.168.130.7; server 192.168.130.10; } #nginx #启动nginx服务
2）在备节点上配置
# vim /etc/keepalived/keepalived.conf sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 global_defs { notification_email { acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 vrrp_iptables } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 98 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { #虚拟IP 192.168.130.200/24 } } #yum install nginx #装包 #vim /etc/nginx/conf.d/test.conf #创建nginx的配置文件 server { listen 80 default_server; server_name www.a.com; root /usr/share/nginx/html; location / { proxy_pass http://www; } } #vim /etc/nginx/nginx.conf http { #在http上添加 upstream www { server 192.168.130.7; server 192.168.130.10; } #nginx #启动nginx服务
2.分别在后台web1/web2服务器上
#yum install httpd #安装包 echo test1/test2 > /var/www/html/index.html #创建测试主页面
#systemctl start httpd
2.client测试
# curl 192.168.130.200 test2 # curl 192.168.130.200 test1
此时，如果将主节点的nginx程序手动停止（nginx -s stop ），此时的虚拟IP地址将转移到备用节点上。由此实现了高可用。主节点上nginx启动则恢复到主节点上
博客作业
1、lvs + keepalived的双主模型实现
环境：
各节点时间必须同步；
timedatectl set-timezone Asia/Shanghai #centos7上有此命令
确保iptables及selinux的正确配置；
各节点之间可通过主机名互相通信（对KA并非必须），建议使用/etc/hosts文件实现；
确保各节点的用于集群服务的接口支持MULTICAST通信；D类：224-239；
ip link set dev eth0 multicast off | on
1）LVS1配置
# yum install keepalied # vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhoat smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 vrrp_iptables } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 98 advert_int 1 authentication { auth_type PASS auth_pass fd57721a } virtual_ipaddress { 192.168.130.100/24 dev ens33 } } vrrp_instance VI_2 { state BACKUP interface ens33 virtual_router_id 52 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 4a9a407a } virtual_ipaddress { 192.168.130.200/24 dev ens33 } } virtual_server 192.168.130.100 80 { delay_loop 2 lb_algo rr lb_kind DR protocol TCP real_server 192.168.130.7 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } real_server 192.168.130.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } } virtual_server 192.168.1300.200 80 { delay_loop 2 lb_algo rr lb_kind DR protocol TCP real_server 192.168.130.7 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } real_server 192.168.130.10 80 { weight 1HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } real_server 192.168.130.10 80 { weight 1 HTTP_GET { url { path / status_code 200 } connect_timeout 2 nb_get_retry 3 delay_before_retry 1 } } } #systemctl start keepalived
#ip a l
2）LVS2配置
# yum install keepalied
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhoat
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.111.111
vrrp_iptables
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass fd57721a
}
virtual_ipaddress {
192.168.130.100/24 dev ens33
}
}
vrrp_instance VI_2 {
state MASTER
interface ens33
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 4a9a407a
}
virtual_ipaddress {
192.168.130.200/24 dev ens33
}
}
virtual_server 192.168.130.100 80 {
delay_loop 2
lb_algo rr
lb_kind DR
protocol TCP
real_server 192.168.130.7 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.130.10 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
virtual_server 192.168.1300.200 80 {
delay_loop 2
lb_algo rr
lb_kind DR
protocol TCP
real_server 192.168.130.7 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.130.10 80 {
weight 1HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 192.168.130.10 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
#systemctl start keepalived
#ip a l
同时启动两台机子服务后对应网卡主节点上绑定虚拟IP
3)后台web服务器web1/web2上：配置脚本
# vim /etc/web.sh #!/bin/bash # vip="192.168.130.100/32" vip2="192.168.130.200/32" iface="lo" 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 ip addr add $vip label $iface:0 broadcast ${vip%/*} dev $iface ip addr add $vip2 label $iface:1 broadcast ${vip2%/*} dev $iface ip route add $vip dev $iface ip route add $vip2 dev $iface ;; stop) ip addr flush dev $iface ip route flush dev $iface 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 "Usage: `basename $0` start | stop" 1>&2 ;; esac #bash /etc/web.sh start
3）在client上访问虚拟IP
# curl 192.168.130.200 test2 # curl 192.168.130.200 test1 # curl 192.168.130.100 test2 # curl 192.168.130.100 test1
2、keepalived + haproxy 实现调度器的高可用
在主节点上配置
1）配置haproxy实现负载均衡的功能
#yum install haproxy -y #安装包 # vim /etc/haproxy/haproxy.cfg #修改配置文件 frontend web *:80 default_backend websrvs backend websrvs balance roundrobin server srv1 192.168.130.7:80 check server srv2 192.168.130.10:80 check
#systemctl start haproxy
2）配置keepalived实现高可用
# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhoat smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 vrrp_iptables } vrrp_script chk_haproxy { script "killall -0 haproxy" #监控haproxy进程 interval 1 weight -5 fall 2 rise 1 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass fd57721a } virtual_ipaddress { 192.168.130.100/24 dev ens33 } track_script { #调用监控脚本 chk_haproxy } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" }
在从节点上配置
1）配置haproxy实现负载均衡的功能
#yum install haproxy -y #安装包
# vim /etc/haproxy/haproxy.cfg #修改配置文件
frontend web *:80
default_backend websrvs
backend websrvs
balance roundrobin
server srv1 192.168.130.7:80 check
server srv2 192.168.130.10:80 check
#systemctl start haproxy
2）配置keepalived实现高可用
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhoat
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
vrrp_mcast_group4 224.0.111.111
vrrp_iptables
}
vrrp_script chk_haproxy {
script "killall -0 haproxy" #监控haproxy进程
interval 1
weight -5
fall 2
rise 1
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass fd57721a
}
virtual_ipaddress {
192.168.130.100/24 dev ens33
}
track_script { #调用监控脚本
chk_haproxy
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
在web服务器上：配置脚本
# vim /etc/web.sh #!/bin/bash # vip="192.168.130.100/32" vip2="192.168.130.200/32" iface="lo" 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 ip addr add $vip label $iface:0 broadcast ${vip%/*} dev $iface ip addr add $vip2 label $iface:1 broadcast ${vip2%/*} dev $iface ip route add $vip dev $iface ip route add $vip2 dev $iface ;; stop) ip addr flush dev $iface ip route flush dev $iface 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 "Usage: `basename $0` start | stop" 1>&2 ;; esac #bash /etc/web.sh start
在client上访问
# curl 192.168.130.100:80 test2 # curl 192.168.130.100:80 test1
3、利用脚本功能实现keepalived的维护模式
! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhoat smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 224.0.111.111 vrrp_iptables } vrrp_script chk_down { script "/bin/bash -c '[[ -f /etc/keepalived/down ]]' && exit 1 || exit 0"
#在keepalived中要特别地指明作为bash的参数的运行 interval 1 weight -10 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass fd57721a } virtual_ipaddress { 192.168.130.100/24 dev ens33 } track_script { chk_down #调用脚本 } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" } 测试：创建down文件后使得降优先级，从而使得VIP漂移到node2，进入维护模式 [root@node1 ~]# touch /etc/keepalived/down
4、编写Ansible角色批量部署keepalived + nginx 实现双主模型下反向代理器的高可用
以下操作全部在ansible主机上操作
1）基于秘钥通信：
[root@ansible ~]# vim cpkey.sh #!/bin/bash rpm -q expect &>/dev/null || yum -q -y install expect [ ! -e ~/.ssh/id_rsa ] && ssh-keygen -t rsa -P "" -f ~/.ssh/id_rsa &>/dev/null read -p "Host_ip_list: " ip_list_file read -p "Username: " username read -s -p "Password: " password [ ! -e "$ip_list_file" ] && echo "$ip_list_file not exist." && exit [ -z "$ip_list_file" -o -z "$username" -o -z "$password" ] && echo "input error!" && exit localhost_ip=`hostname -I |cut -d' ' -f1` expect <<EOF set timeout 10 spawn ssh-copy-id -i /root/.ssh/id_rsa.pub $localhost_ip expect { "yes/no" { send "yes "; exp_continue} "password" { send "$password "} } expect eof EOF while read ipaddr1; do expect <<EOF set timeout 10 spawn ssh ${username}@${ipaddr1} ':' expect { "yes/no" { send "yes "; exp_continue} "password" { send "$password "} } expect eof EOF done < "$ip_list_file" while read ipaddr2; do expect <<EOF set timeout 10 spawn scp -pr .ssh/ ${username}@${ipaddr2}: expect { "yes/no" { send "yes "; exp_continue} "password" { send "$password "} } expect eof EOF done < "$ip_list_file" [root@ansible ~]# vim iplist.txt 192.168.130.6 192.168.130.7 192.168.130.8 192.168.130.9 192.168.130.11 192.168.130.12 [root@ansible ~]# ./cpkey.sh Host_ip_list: iplist.txt #指定IP地址列表文件 Username: root Password:centos #密码一致
2）配置内部主机基于主机名通信：
[root@ansible ~]# vim /etc/hosts 92.168.130.7 keep1 192.168.130.8 keep2 192.168.130.10 web1 192.168.130.11 web2 192.168.130.6 DNS 192.168.130.9 ansible [root@ansible ~]# yum install ansible -y #基于epel源 [root@ansible ~]# vim /etc/ansible/hosts [keep] 192.168.130.7 192.168.130.8 [web] 192.168.130.10 192.168.130.11 [dns] 192.168.130.6 [root@ansible ~]# ansible all -m copy -a 'src=/etc/hosts dest=/etc/hosts backup=yes'
3）编写角色，实现web服务的部署
[root@ansible ~]# mkdir -p ansible/roles/web/{tasks,templates,files,handlers} [root@ansible ~]# cd ansible/ [root@ansible ansible]# vim roles/web/tasks/install.yml - name: install httpd yum: name=httpd state=present [root@ansible ansible]# vim roles/web/tasks/copy.yml - name: copy config file template: src=httpd.conf.j2 dest=/etc/httpd/conf/httpd.conf notify: restart service - name: copy index.html template: src=index.html.j2 dest=/var/www/html/index.html owner=apache notify: restart service [root@ansible ansible]# vim roles/web/tasks/start.yml - name: start httpd service: name=httpd state=started [root@ansible ansible]# vim roles/web/tasks/main.yml - include: install.yml - include: copy.yml - include: start.yml [root@ansible ansible]# yum install httpd -y [root@ansible ansible]# cp /etc/httpd/conf/httpd.conf roles/web/templates/httpd.conf.j2 [root@ansible ansible]# vim roles/web/templates/httpd.conf.j2 ServerName {{ ansible_fqdn }} [root@ansible ansible]# vim roles/web/templates/index.html.j2 {{ ansible_fqdn }} test page. [root@ansible ansible]# vim roles/web/handlers/main.yml - name: restart service service: name=httpd state=restarted [root@ansible ansible]# vim web.yml --- - hosts: web remote_user: root roles: - web ... [root@ansible ansible]# ansible-playbook web.yml
4）编写角色，实现nginx反向代理服务的部署
[root@ansible ansible]# mkdir -p roles/nginx_proxy/{files,handlers,tasks,templates} [root@ansible ansible]# vim roles/nginx_proxy/tasks/install.yml - name: install nginx yum: name=nginx state=present [root@ansible ansible]# vim roles/nginx_proxy/tasks/copy.yml - name: copy config file template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf notify: restart service [root@ansible ansible]# vim roles/nginx_proxy/tasks/start.yml - name: start nginx service: name=nginx state=started [root@ansible ansible]# vim roles/nginx_proxy/tasks/main.yml - include: install.yml - include: copy.yml - include: start.yml [root@ansible ansible]# yum install nginx -y [root@ansible ansible]# cp /etc/nginx/nginx.conf roles/nginx_proxy/templates/nginx.conf.j2 [root@ansible ansible]# vim roles/nginx_proxy/templates/nginx.conf.j2 http { upstream websrvs { #后端web服务器的IP地址 server 192.168.130.10; server 192.168.130.11; } server { listen 80 default_server; server_name _; root /usr/share/nginx/html; location / { proxy_pass http://websrvs; } } } [root@ansible ansible]# vim roles/nginx_proxy/handlers/main.yml - name: restart service service: name=nginx state=restarted [root@ansible ansible]# vim nginx_proxy.yml --- - hosts: keep remote_user: root roles: - nginx_proxy ... [root@ansible ansible]# ansible-playbook nginx_proxy.yml
5）编写角色，利用keepalived实现nginx反向代理服务的高可用
[root@ansible ansible]# ansible 192.168.0.8 -m hostname -a 'name=node1' [root@ansible ansible]# ansible 192.168.0.9 -m hostname -a 'name=node2' [root@ansible ansible]# mkdir -p roles/keepalived/{files,handlers,tasks,templates,vars} [root@ansible ansible]# vim roles/keepalived/tasks/install.yml #安装剧本 - name: install keepalived yum: name=keepalived state=present [root@ansible ansible]# vim roles/keepalived/tasks/copy.yml #复制配置文件剧本 - name: copy configure file template: src=keepalived.conf.j2 dest=/etc/keepalived/keepalived.conf notify: restart service when: ansible_fqdn == "node1" #选择性复制，将第一套配置文件复制到node1上 - name: copy configure file2 template: src=keepalived.conf2.j2 dest=/etc/keepalived/keepalived.conf notify: restart service when: ansible_fqdn == "node2" #将第二套配置文件复制到node2上 [root@ansible ansible]# vim roles/keepalived/tasks/start.yml #启动服务 - name: start keepalived service: name=keepalived state=started [root@ansible ansible]# vim roles/keepalived/tasks/main.yml - include: install.yml - include: copy.yml - include: start.yml [root@ansible ansible]# vim roles/keepalived/vars/main.yml #自定义变量 kepd_vrrp_mcast_group4: "224.0.111.222" #组播地址 kepd_interface_1: "ens33" kepd_virtual_router_id_1: "51" #虚拟路由标识ID kepd_priority_1: "100" #优先级 kepd_auth_pass_1: "fd57721a" #简单认证密码，8位 kepd_virtual_ipaddress_1: "192.168.130.100/24" #VIP地址，此处应该为公网地址 kepd_interface_2: "ens33" kepd_virtual_router_id_2: "52" kepd_priority_2: "98" kepd_auth_pass_2: "41af6acc" kepd_virtual_ipaddress_2: "192.168.130.200/24" [root@ansible ansible]# yum install keepalived -y [root@ansible ansible]# cp /etc/keepalived/keepalived.conf roles/keepalived/templates/keepalived.conf.j2 [root@ansible ansible]# vim roles/keepalived/templates/keepalived.conf.j2 #编辑配置文件模板 ! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhoat smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id node1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 {{ kepd_vrrp_mcast_group4 }} vrrp_iptables } vrrp_script chk_nginx { #脚本定义 script "killall -0 nginx" interval 1 weight -5 fall 2 rise 1 } vrrp_instance VI_1 { state MASTER interface {{ kepd_interface_1 }} virtual_router_id {{ kepd_virtual_router_id_1 }} priority {{ kepd_priority_1 }} advert_int 1 authentication { auth_type PASS auth_pass {{ kepd_auth_pass_1 }} } virtual_ipaddress { {{ kepd_virtual_ipaddress_1 }} } track_script { chk_nginx } } vrrp_instance VI_2 { state BACKUP interface {{ kepd_interface_2 }} virtual_router_id {{ kepd_virtual_router_id_2 }} priority {{ kepd_priority_2 }} advert_int 1 authentication { auth_type PASS auth_pass {{ kepd_auth_pass_2 }} } virtual_ipaddress { {{ kepd_virtual_ipaddress_2 }} } track_script { chk_nginx } } [root@ansible ansible]# cp roles/keepalived/templates/keepalived.conf.j2 roles/keepalived/templates/keepalived.conf2.j2 [root@ansible ansible]# vim roles/keepalived/templates/keepalived.conf2.j2 #编写第二套配置文件，和第一套不同的只有state和priority参数需要改 ! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhoat smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id keep1 vrrp_skip_check_adv_addr vrrp_strict vrrp_garp_interval 0 vrrp_gna_interval 0 vrrp_mcast_group4 {{ kepd_vrrp_mcast_group4 }} vrrp_iptables } vrrp_script chk_nginx { script "killall -0 nginx" interval 1 weight -5 fall 2 rise 1 } vrrp_instance VI_1 { state BACKUP interface {{ kepd_interface_1 }} virtual_router_id {{ kepd_virtual_router_id_1 }} priority {{ kepd_priority_2 }} advert_int 1 authentication { auth_type PASS auth_pass {{ kepd_auth_pass_1 }} } virtual_ipaddress { {{ kepd_virtual_ipaddress_1 }} } track_script { chk_nginx } } vrrp_instance VI_2 { state MASTER interface {{ kepd_interface_2 }} virtual_router_id {{ kepd_virtual_router_id_2 }} priority {{ kepd_priority_1 }} advert_int 1 authentication { auth_type PASS auth_pass {{ kepd_auth_pass_2 }} } virtual_ipaddress { {{ kepd_virtual_ipaddress_2 }} } track_script { chk_nginx } } [root@ansible ansible]# vim roles/keepalived/handlers/main.yml #实现配置文件变动时触发重启服务操作 - name: restart service service: name=keepalived state=restarted [root@ansible ansible]# vim keepalived.yml --- - hosts: node remote_user: root roles: - keepalived ... [root@ansible ansible]# ansible-playbook keepalived.yml
6）配置DNS
[root@DNS ~]# yum install bind -y [root@DNS ~]# vim /etc/named.conf [root@DNS ~]# vim /etc/named.conf #将以下参数注释 //listen-on port 53 { 127.0.0.1; }; //allow-query { localhost; }; [root@DNS ~]# vim /etc/named.rfc1912.zones zone "magedu.tech" { type master; file "magedu.tech.zone"; }; [root@DNS ~]# vim /var/named/magedu.tech.zone $TTL 1D @ IN SOA DNS1.magedu.tech. admin.magedu.tech. ( 1 1D 1H 1W 3H ) NS DNS1 DNS1 A 192.168.130.6 www A 192.168.130.100 www A 192.168.130.200 [root@DNS ~]# named-checkconf [root@DNS ~]# named-checkzone "magedu.tech" /var/named/magedu.tech.zone zone magedu.tech/IN: loaded serial 1 OK [root@DNS ~]# service named start Starting named: named: already running [ OK ] [root@DNS ~]# dig www.magedu.tech @192.168.130.6 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6 <<>> www.magedu.tech @192.168.130.6 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9734 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 1 ;; QUESTION SECTION: ;www.magedu.tech. IN A ;; ANSWER SECTION: www.magedu.tech. 86400 IN A 192.168.130.200 www.magedu.tech. 86400 IN A 192.168.130.100 ;; AUTHORITY SECTION: magedu.tech. 86400 IN NS dns1.magedu.tech. ;; ADDITIONAL SECTION: dns1.magedu.tech. 86400 IN A 192.168.130.6 ;; Query time: 0 msec ;; SERVER: 192.168.130.6#53(192.168.130.6) ;; WHEN: Sat Jul 14 18:20:56 2018 ;; MSG SIZE rcvd: 100
7）客户端模拟测试
[root@client ~]# vim /etc/resolv.conf nameserver 192.168.130.6 [root@client ~]# for i in {1..2}; do curl www.magedu.tech; done web2 test page. web1 test page.