7.haproxy安装配置
下载编译安装：
wget http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.11.tar.gz
tar xvzf haproxy-1.4.11.tar.gz
cd haproxy-1.4.11
make TARGET=linux26 ARCH=x86_64
make install
配置
vi /etc/haproxy.cfg
global
maxconn 40000
debug
#quiet
user haproxy
group haproxy
nbproc 1
log 127.0.0.1 local3
spread-checks 2
defaults
timeout server  3s
timeout connect 3s
timeout client  60s
timeout http-request 3s
timeout queue   3s
frontend db_write
bind 192.168.5.10:3306
default_backend cluster_db_write
frontend db_read
bind 192.168.5.20:3306
default_backend cluster_db_read
frontend web_haproxy_status
bind :80
default_backend web_status
frontend monitor_mdb1
bind 127.0.0.1:9301
mode http
acl no_repl_mdb1 nbsrv(mdb1_replication) eq 0
acl no_repl_mdb2 nbsrv(mdb2_replication) eq 0
acl no_mdb1 nbsrv(mdb1_status) eq 0
acl no_mdb2 nbsrv(mdb2_status) eq 0
monitor-uri /dbs
monitor fail unless no_repl_mdb1 no_repl_mdb2 no_mdb2
monitor fail if no_mdb1 no_mdb2
frontend monitor_mdb2
bind 127.0.0.1:9302
mode http
acl no_repl_mdb1 nbsrv(mdb1_replication) eq 0
acl no_repl_mdb2 nbsrv(mdb2_replication) eq 0
acl no_mdb1 nbsrv(mdb1_status) eq 0
acl no_mdb2 nbsrv(mdb2_status) eq 0
monitor-uri /dbs
monitor fail unless no_repl_mdb1 no_repl_mdb2 no_mdb1
monitor fail if no_mdb1 no_mdb2
frontend monitor_sdb1
bind 127.0.0.1:9303
mode http
acl no_repl_sdb1 nbsrv(sdb1_replication) eq 0
acl no_repl_mdb1 nbsrv(mdb1_replication) eq 0
acl no_mdb2 nbsrv(mdb2_status) eq 1
monitor-uri /dbs
monitor fail if no_repl_sdb1
monitor fail if no_repl_mdb1 no_mdb2
frontend monitor_sdb2
bind 127.0.0.1:9304
mode http
acl no_repl_sdb2 nbsrv(sdb2_replication) eq 0
acl no_repl_mdb1 nbsrv(mdb1_replication) eq 0
acl no_mdb2 nbsrv(mdb2_status) eq 1
monitor-uri /dbs
monitor fail if no_repl_sdb2
monitor fail if no_repl_mdb1 no_mdb2
frontend monitor_sdb3
bind 127.0.0.1:9305
mode http
acl no_repl_sdb3 nbsrv(sdb3_replication) eq 0
acl no_repl_mdb2 nbsrv(mdb2_replication) eq 0
acl no_mdb1 nbsrv(mdb1_status) eq 1
monitor-uri /dbs
monitor fail if no_repl_sdb3
monitor fail if no_repl_mdb2 no_mdb1
frontend monitor_sdb4
bind 127.0.0.1:9306
mode http
acl no_repl_sdb4 nbsrv(sdb4_replication) eq 0
acl no_repl_mdb2 nbsrv(mdb2_replication) eq 0
acl no_mdb1 nbsrv(mdb1_status) eq 1
monitor-uri /dbs
monitor fail if no_repl_sdb4
monitor fail if no_repl_mdb2 no_mdb1
frontend monitor_splitbrain
bind 127.0.0.1:9300
mode http
acl no_repl01 nbsrv(mdb1_replication) eq 0
acl no_repl02 nbsrv(mdb2_replication) eq 0
acl mdb1 nbsrv(mdb1_status) eq 1
acl mdb2 nbsrv(mdb2_status) eq 1
monitor-uri /dbs
monitor fail unless no_repl01 no_repl02 mdb1 mdb2
backend mdb1_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server mdb1 192.168.5.11:3306 check port 9201 inter 1s rise 1 fall 1
backend mdb2_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server mdb2 192.168.5.12:3306 check port 9201 inter 1s rise 1 fall 1
backend sdb1_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server sdb1 192.168.5.21:3306 check port 9201 inter 1s rise 1 fall 1
backend sdb2_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server sdb2 192.168.5.22:3306 check port 9201 inter 1s rise 1 fall 1
backend sdb3_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server sdb3 192.168.5.23:3306 check port 9201 inter 1s rise 1 fall 1
backend sdb4_replication
mode tcp
balance roundrobin
option tcpka
option httpchk
server sdb4 192.168.5.24:3306 check port 9201 inter 1s rise 1 fall 1
backend mdb1_status
mode tcp
balance roundrobin
option tcpka
option httpchk
server mdb1 192.168.5.11:3306 check port 9200 inter 1s rise 2 fall 2
backend mdb2_status
mode tcp
balance roundrobin
option tcpka
option httpchk
server mdb2 192.168.5.12:3306 check port 9200 inter 1s rise 2 fall 2
backend cluster_db_write
mode    tcp
option  tcpka
balance roundrobin
option  httpchk GET /dbs
server  mdb1 192.168.5.11:3306 weight 1 check port 9201 inter 1s rise 5 fall 1
server  mdb2 192.168.5.12:3306 weight 1 check port 9201 inter 1s rise 5 fall 1 backup
server  mdb1_backup 192.168.5.11:3306 weight 1 check port 9301 inter 1s rise 2 fall 2 addr 127.0.0.1 backup
server  mdb2_backup 192.168.5.12:3306 weight 1 check port 9302 inter 1s rise 2 fall 2 addr 127.0.0.1 backup
backend cluster_db_read
mode    tcp
option  tcpka
balance roundrobin
option  httpchk GET /dbs
server  mdb1 192.168.5.11:3306 weight 1 track cluster_db_write/mdb1
server  mdb2 192.168.5.12:3306 weight 1 track cluster_db_write/mdb2
server  mdb1_backup 192.168.5.11:3306 weight 1 track cluster_db_write/mdb1_backup
server  mdb2_backup 192.168.5.12:3306 weight 1 track cluster_db_write/mdb2_backup
server  mdb1_splitbrain 192.168.5.11:3306 weight 1 check port 9300 inter 1s rise 1 fall 2 addr 127.0.0.1
server  mdb2_splitbrain 192.168.5.12:3306 weight 1 check port 9300 inter 1s rise 1 fall 2 addr 127.0.0.1
server  sdb1_slave 192.168.5.21:3306 weight 1 check port 9303 inter 1s rise 5 fall 1 addr 127.0.0.1
server  sdb2_slave 192.168.5.22:3306 weight 1 check port 9304 inter 1s rise 5 fall 1 addr 127.0.0.1
server  sdb3_slave 192.168.5.23:3306 weight 1 check port 9305 inter 1s rise 5 fall 1 addr 127.0.0.1
server  sdb4_slave 192.168.5.24:3306 weight 1 check port 9306 inter 1s rise 5 fall 1 addr 127.0.0.1
backend  web_status
mode http
stats enable
# stats scope
# stats hide-version
stats refresh 5s
stats uri /status
stats realm Haproxy\ statistics
stats auth ylmf:gaojinbo
8.测试
1）正常情况，backup和splitbrain状态down
2）停止mdb2复制，mdb2和sdb3,sdb4状态down，数据库仍可读写
3)同时停止mdb1,mdb2复制，mdb1和sdb1,sdb2,sdb3,sdb4状态down，数据库只能读
4）关闭mdb1数据库，mdb1,mdb2和sdb1,sdb2状态down，数据库仍可读写
5）关闭mdb2数据库，mdb1,mdb2和sdb3,sdb4状态down，数据库仍可读写
完成！