2015-06-03ha High-availability clusters

HA (high available) is highly available and is also known as a dual-machine hot standby for critical business. The simple understanding is that there are two machines A and B, the normal is a service, B standby idle, when a down or service outage, will switch to the B machine to continue to provide services. Commonly used high-availability open source software has heartbeat and keepalived, where keepalived has load-balanced functionality.
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Below we use heartbeat to do the HA cluster, and the Nginx service as the HA corresponding service.
Test Preparation:
Two machines, all centos6.5, Nic Eth0 IP is as follows:
Aming 192.168.31.166
Aming1 192.168.31.100
Two eth1 IPs are as follows:
Aming 192.168.21.166
Aming1 192.168.21.100
The following operations 1-5 are operated on two machines
1. Hostname set up for aming and aming1, respectively
2. Close the firewall iptables-f;
Close Selinux:setenforce 0
3. Vi/etc/hosts//Add the following:
192.168.31.166 aming
192.168.31.100 aming1
4. Install the Epel extension Source:
Rpm-ivh ' http://www.lishiming.net/data/attachment/forum/epel-release-6-8_32.noarch.rpm '
5. Two machines are installed Heartbeat/libnet
Yum install-y heartbeat* libnet nginx
6. Lord (aming) configuration
cd/usr/share/doc/heartbeat-3.0.4/
CP Authkeys HA.CF haresources/etc/ha.d/
Cd/etc/ha.d
VI Authkeys//Join
3 MD5 hello!
chmod Authkeys
VI haresources//Join
Aming 192.168.31.110/24/eth0:0 Nginx
VI ha.cf//change to the following:
Debugfile/var/log/ha-debug
Logfile/var/log/ha-log
Logfacility local0
KeepAlive 2
Deadtime 30
Warntime 10
Initdead 60
Udpport 694
Ucast eth1 192.168.21.100
Auto_failback on
Node aming
Node Aming1
Ping 192.168.21.1
Respawn Hacluster/usr/lib/heartbeat/ipfail
7. Copy the three configurations from the Lord to the top:
cd/etc/ha.d/
SCP Authkeys ha.cf haresources aming1:/etc/ha.d/
8. To the top (aming1) Edit HA.CF
VI/ETC/HA.D/HA.CF//Only need to change one place
Ucast eth1 192.168.21.100 changed to Ucast eth1 192.168.21.166
9. Start Heartbeat:
Guthrie, after from
Service Heartbeat Start
10. Inspection Test
Ifconfig See if there is eth0:0
PS aux |grep Nginx See if there is nginx process
11. Test 1
The Lord deliberately forbidden Ping
Iptables-i input-p icmp-j DROP
12. Test 2
Lord Stop Heartbeat Service
Service Heartbeat Stop
13. Test for Brain fissure
Master and slave down eth1 NIC
Ifdown eth1
Extended Learning
Respawn Hacluster/usr/lib64/heartbeat/ipfail
The path should be aware of the differences between 32-bit and 64-bit systems, where errors can cause heartbeat to start unsuccessfully
Do not start it when you are finished loading Nginx

Http://www.apelearn.com/bbs/forum.php?mod=viewthread&tid=7039&highlight=heartbeat
About the Heartbeat profile Reference document: Http://blog.chinaunix.net/uid-20749043-id-1878328.html
Heartbeat and keepalived compare http://blog.csdn.net/yunhua_lee/article/details/9788433 http://zhengdl126.iteye.com/blog/1738012
DRBD working principle and configuration http://502245466.blog.51cto.com/7559397/1298945

2015-06-03ha High-availability clusters