一、介紹
有些情況下，可能MySQL Router不便裝在每個應用所在的伺服器上，那麼這時候要解決MySQL Router的單點故障，就需要用到keepalived或者pacemaker了，本文介紹了MySQL Router HA通過keepalived來實作。
二、環境準備
IP位址
角色
172.16.8.53
MySQL Router+MASTER
172.16.8.68
MySQL Router+BACKUP
172.16.8.24
VIP
keepalived版本：2.0.18
三、安裝步驟
3.1下載下傳軟體包，解壓
mkdir /software
wget https://www.keepalived.org/software/keepalived-2.0.18.tar.gz -P /software
tar -zxvf /software/keepalived-2.0.18.tar.gz ; cd /software/keepalived
3.2源碼安裝
yum -y install openssl* libnl‐dev* gcc-c++
./configure --prefix=/usr/local/keepalived
make
make install
3.3配置keepalived
mkdir /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /data/keepalived-2.0.18/keepalived/etc/init.d/keepalived /etc/init.d/
cp /data/keepalived-2.0.18/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
3.4修改keepalived配置檔案
3.4.1以下在Keepalived MASTER上修改
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server smtp.139.com
smtp_connect_timeout 30
router_id Router1
vrrp_skip_check_adv_addr
# vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_script chk_mysqlrouter {
script "/usr/bin/killall -0 /usr/bin/mysqlrouter" # check the haproxy process
interval 2 # every 2 seconds
weight 2 # add 2 points if OK
fall 2
}
vrrp_instance VI_1 {
state MASTER
interface ens160
virtual_router_id 51
priority 102
advert_int 1
virtual_ipaddress {
172.16.8.24
}
track_script {
chk_mysqlrouter
}
notify_master "/usr/bin/python /data/keepalived_monitor/keepalived_notify.py master 172.16.8.53 172.168.8.24"
notify_backup "/usr/bin/python /data/keepalived_monitor/keepalived_notify.py backup 172.16.8.53 172.168.8.24"
}
3.4.2以下在Keepalived BACKUP上修改
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server smtp.139.com
smtp_connect_timeout 30
router_id Router2
vrrp_skip_check_adv_addr
# vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_script chk_mysqlrouter {
script "/usr/bin/killall -0 /usr/bin/mysqlrouter" # check the haproxy process
interval 2 # every 2 seconds
weight 2 # add 2 points if OK
fall 2
}
vrrp_instance VI_1 {
state BACKUP
interface ens160
virtual_router_id 51
priority 101
advert_int 1
virtual_ipaddress {
172.16.8.24
}
track_script {
chk_mysqlrouter
}
notify_master "/usr/bin/python /data/keepalived_monitor/keepalived_notify.py master 172.16.8.68 172.168.8.24"
notify_backup "/usr/bin/python /data/keepalived_monitor/keepalived_notify.py backup 172.16.8.68 172.168.8.24"
}
說明：
/usr/bin/killall -0 /usr/bin/mysqlrouter，每2秒鐘會執行一次，監測mysqlrouter程序是否存在，一旦超過2次不正常，則會且換vip到BACKUP，并且執行keepalived_notify.py郵件報警腳本發送告警郵件
發送郵箱請自行設定
3.5啟動keepalived
systemctl start keepalived
systemctl enable keepalived
啟動參數說明：
使用systemctl start keepalived指令啟動服務時，預設會将/etc/sysconfig/keepalived檔案中KEEPALIVED_OPTIONS參數作為keepalived服務啟動時的參數，并從/etc/keepalived/目錄下加載keepalived.conf配置檔案，或用-f參數指定配置檔案的位置。
3.6檢視VIP綁定情況
以下是MASTER
[[email protected] keepalived_monitor]# ip a
1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens160: mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:50:56:99:45:ad brd ff:ff:ff:ff:ff:ff
inet 172.16.8.53/24 brd 172.16.8.255 scope global noprefixroute ens160
valid_lft forever preferred_lft forever
inet 172.16.8.24/32 scope global ens160
valid_lft forever preferred_lft forever
inet6 fe80::170e:b457:5dbd:d629/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: docker0: mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:c3:9f:ab:0e brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 scope global docker0
valid_lft forever preferred_lft forever
4: [email protected]: mtu 1440 qdisc noqueue state UNKNOWN group default qlen 1000
link/ipip 0.0.0.0 brd 0.0.0.0
inet 10.233.71.0/32 scope global tunl0
valid_lft forever preferred_lft forever
可以看到VIP：172.16.8.24已經綁定到ens160網卡上
以下是BACKUP
[[email protected] mysqlrouter]# ip a
1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens160: mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:50:56:99:1c:0f brd ff:ff:ff:ff:ff:ff
inet 172.16.8.68/24 brd 172.16.8.255 scope global noprefixroute ens160
valid_lft forever preferred_lft forever
inet6 fe80::25a1:8b8d:a00e:70dd/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: docker0: mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:00:4f:fb:9b brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 scope global docker0
valid_lft forever preferred_lft forever
4: [email protected]: mtu 1440 qdisc noqueue state UNKNOWN group default qlen 1000
link/ipip 0.0.0.0 brd 0.0.0.0
inet 10.233.74.64/32 scope global tunl0
valid_lft forever preferred_lft forever
BACKUP是沒有綁定VIP的，隻有當MASTER發生故障，觸發了VIP切換，BACKUP才會綁定VIP
四、郵件告警
郵件告警腳本如下，需要在MASTER和BACKUP上都部署
[[email protected] keepalived_monitor]# cat keepalived_notify.py
#!/usr/bin/python
# -*- coding:utf-8 -*-
import smtplib
from email.mime.text import MIMEText
from email.header import Header
import sys, time, subprocess
# 第三方 SMTP 服務
mail_host="smtp.139.com" #設定伺服器
mail_user="[email protected]" #使用者名
mail_pass="xxx" #密碼
sender = '[email protected]' # 郵件發送者
receivers = ['[email protected]', '[email protected]'] # 接收郵件，可設定為你的QQ郵箱或者其他郵箱
p = subprocess.Popen('hostname', shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
hostname = p.stdout.readline().split('\n')[0]
message_to = ''
for i in receivers:
message_to += i + ';'
def print_help():
note = '''python script.py role ip vip
'''
print(note)
exit(1)
time_stamp = time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time()))
if len(sys.argv) != 4:
print_help()
elif sys.argv[1] == 'master':
message_content = '%s server: %s(%s) change to Master, VIP: %s' %(time_stamp, sys.argv[2], hostname, sys.argv[3])
subject = '%s change to Master -- keepalived notify' %(sys.argv[2])
elif sys.argv[1] == 'backup':
message_content = '%s server: %s(%s) change to Backup, VIP: %s' %(time_stamp, sys.argv[2], hostname, sys.argv[3])
subject = '%s change to Backup -- keepalived notify' %(sys.argv[2])
else:
print_help()
message = MIMEText(message_content, 'plain', 'utf-8')
message['From'] = Header(sender, 'utf-8')
message['To'] = Header(message_to, 'utf-8')
message['Subject'] = Header(subject, 'utf-8')
try:
smtpObj = smtplib.SMTP()
smtpObj.connect(mail_host, 25) # 25 為 SMTP 端口号
smtpObj.login(mail_user,mail_pass)
smtpObj.sendmail(sender, receivers, message.as_string())
print("郵件發送成功")
except smtplib.SMTPException as e:
print("Error: 無法發送郵件")
print(e)
五、問題彙總
5.1沒有killall指令
解決辦法：yum install psmisc
5.2VIP無法ping通
解決辦法：關閉防火牆和SELinux，如果要開啟防火牆的話，需要開放keepalived的多點傳播端口