一、HA（high available)高可用集羣
常用HA方案：
keepalived使用VRRP（心跳可以走業務網絡）協議，安裝配置維護簡單，適用於小型網絡
Hearbeat使用心跳（必須有專門的心跳網絡）進行通信和選舉，安裝配置維護複雜，適用於大型網絡
使用建議：優先使用Keepalived，當Keepalived不夠用的時候才選擇Heartbeat
二、使用hearbeat實現
1.更改相應環境
/etc/init.d/iptables stop getenforce hostname master logout #關閉防火牆和Selinux，臨時配置主機名，登出生效 /etc/init.d/iptables stop getenforce hostname slave logout vim /etc/hosts 192.168.1.200 master 192.168.1.201 slave #修改兩臺主機的hosts文件，添加如上內容 wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo wget -P /etc/yum.repos.d/ http://mirrors.aliyun.com/repo/epel-6.repo yum clean all yum makecache #安裝阿里yum源及擴展源 yum install -y heartbeat libnet #安裝heartbeat及其依賴包libnet
三、配置heartbeat
cd /usr/share/doc/heartbeat-3.0.4/ cp authkeys ha.cf haresources /etc/ha.d/ #拷貝配置文件模板 vim /etc/ha.d/authkeys #編輯主從通信文件，使用md5加密 auth 3 #1 crc #2 sha1 HI! 3 md5 Hello! chmod 600 /etc/ha.d/authkeys #更改文件權限 vim /etc/ha.d/haresources #找到#node1 10.0.0.170 ，修改成如下 master 192.168.1.205/24/eth0:0 nginx cp /etc/ha.d/ha.cf /etc/ha.d/ha.cf.bak > /etc/ha.d/ha.cf vim /etc/ha.d/ha.cf #添加如下內容 debugfile /var/log/ha-debug #排錯日誌 logfile /var/log/ha-log logfacility local0 keepalive 2 #探測間隔 deadtime 30 #死亡間隔 warntime 10 #警告間隔 initdead 60 #預留間隔 udpport 694 #心跳通信端口 ucast eth0 192.168.1.201 #指定單播，從網卡0出去，對端IP爲1.201 auto_failback on #是否允許主從強佔 node master node slave ping 192.168.1.1 #仲裁IP，一般配置爲網關 respawn hacluster /usr/lib64/heartbeat/ipfail #檢測網絡連通性，注意32位和64位路徑不同 cd /etc/ha.d/ scp -P60522 authkeys haresources ha.cf slave:/etc/ha.d/ #將配置文件拷貝至slave vim /etc/ha.d/ha.cf #到slave上，更改對端IP，若網卡不同，還需更改網卡 ucast eth0 192.168.1.200
四、測試
yum install nginx -y #主從服務器上都安裝nginx作爲測試 /etc/init.d/heartbeat start #先啓動主 echo "111master" > /usr/share/nginx/html/index.html ps aux | grep nginx #nginx會自動啓動，需要等待 /etc/init.d/heartbeat start #再啓動從 echo "222slave" > /usr/share/nginx/html/index.html /etc/init.d/heartbeat stop #關閉主 #從上日誌信息 tail -f /var/log/ha-log Jan 25 08:46:26 slave heartbeat: [2100]: WARN: node master: is dead Jan 25 08:46:26 slave heartbeat: [2100]: info: Dead node master gave up resources. Jan 25 08:46:26 slave heartbeat: [2100]: info: Link master:eth0 dead. Jan 25 08:46:26 slave ipfail: [2127]: info: Status update: Node master now has status dead Jan 25 08:46:27 slave ipfail: [2127]: info: NS: We are still alive! Jan 25 08:46:27 slave ipfail: [2127]: info: Link Status update: Link master/eth0 now has status dead Jan 25 08:46:29 slave ipfail: [2127]: info: Asking other side for ping node count. Jan 25 08:46:29 slave ipfail: [2127]: info: Checking remote count of ping nodes. #從會自動啓動eth0:0虛擬網卡和Nginx服務 [root@slave ha.d]# ip add 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:1b:4e:e9 brd ff:ff:ff:ff:ff:ff inet 192.168.1.201/24 brd 192.168.1.255 scope global eth0 inet 192.168.1.205/24 brd 192.168.1.255 scope global secondary eth0:0 inet6 fe80::20c:29ff:fe1b:4ee9/64 scope link valid_lft forever preferred_lft forever [root@slave ha.d]# ps aux | grep nginx root 2665 0.0 0.2 96464 2100 ? Ss 08:45 0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf nginx 2667 0.0 0.2 96852 2740 ? S 08:45 0:00 nginx: worker process root 2686 0.0 0.0 103248 872 pts/0 S+ 08:46 0:00 grep nginx