單主模式Keepalive之Nginx 調度
實驗目的:
實現Nginx調度的高可用,當一臺Nginx調度器故障時,啟用備用的Nginx調度,在架構中,啟用了kepalive節點狀態通知腳本機制,當keepalive的狀態由MASTER變為BACKUP或由BACKUP變為MASTER時,以郵件通知用戶,通過在通知腳本文件中定義BACKUP狀態的節點啟用nginx服務,是為了防止因Nginx服務故障導致節點權重降低從而變為BACKUP狀態,為了避免此種現象,故在轉換為BACKUP狀態時需啟動一次Nginx服務。
實驗環境
keepalive-A 172.16.253.108
keepalive-B 172.16.253.105
Nginx-A 172.16.253.108
Nginx-B 172.16.253.105
LVS-RS1 172.16.250.127
LVS-RS2 172.16.253.193
VIP 172.16.253.150
client 172.16.253.177
web服務集群
為了更好的觀察實驗結果,故在此將RS1和RS2的web頁面內容設置不一致,以致可以更清晰的區分RS1服務端和RS2服務端
LVS-RS1
[root@LVS-RS1 ~]# systemctl restart chronyd \\多臺服務器時間同步
[root@LVS-RS1 ~]# iptables -F
[root@LVS-RS1 ~]# setenforce 0
[root@LVS-RS1 ~]# yum -y install nginx
[root@LVS-RS1 ~]# vim /usr/share/nginx/html/index.html
<h1> Web RS1 </h1>
[root@LVS-RS1 ~]# systemctl start nginx
LVS-RS2
[root@LVS-RS2 ~]# systemctl restart chronyd \\多臺服務器時間同步
[root@LVS-RS2 ~]# iptables -F
[root@LVS-RS2 ~]# setenforce 0
[root@LVS-RS2 ~]# yum -y install nginx
[root@LVS-RS2 ~]# vim /usr/share/nginx/html/index.html
<h1> Web RS2 </h1>
[root@LVS-RS2 ~]# systemctl start nginx
nginx調度集群
nginx-A
[root@nginx-A ~]# yum -y install nginx
[root@nginx-A ~]# vim /usr/share/nginx/html/index.html
</h1> sorry from keepalive-A </h1>
[root@nginx-A ~]# vim /etc/nginx/nginx.conf
http {
upstream websrvs {
server 172.16.250.127:80;
server 172.16.253.193:80;
}
}
server {
listen 80 default_server;
location / {
proxy_pass http://websrvs;
}
}
[root@nginx-A ~]# systemctl start nginx
nginx-B
[root@nginx-B ~]# yum -y install nginx
[root@nginx-B ~]# vim /usr/share/nginx/html/index.html
</h1> sorry from keepalive-B </h1>
[root@nginx-B ~]# vim /etc/nginx/nginx.conf
http {
upstream websrvs {
server 172.16.250.127:80;
server 172.16.253.193:80;
}
}
server {
listen 80 default_server;
location / {
proxy_pass http://websrvs;
}
}
[root@nginx-B ~]# systemctl start nginx
keepalive集群
keepalive-A
[root@keepalive-A ~]# yum -y install keepalived
[root@keepalive-A ~]# vim /etc/keepalived/notify.sh \\定義狀態檢測通知腳本,當節點變為BACKUP時,啟動nginx服務
#!/bin/bash
#
contact='root@localhost' \\通知的聯系者,即本地郵件服務器的通知郵件接受者
notify() {
local mailsubject="$(hostname) to be $1, vip floating" \\指定郵件標題
local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1" \\指定郵件正文
echo "$mailbody" | mail -s "$mailsubject" $contact \\發送通知信息郵件到郵件接收者
}
case $1 in
master)
notify master
;;
backup)
notify backup
systemctl start nginx
;;
fault)
notify fault
;;
*)
echo "Usage: $(basename $0) {master|backup|fault}"
exit 1
;;
esac
[root@keepaliveA ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down { \\定義檢測腳本
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" \\檢測/etc/keepalived/down文件是否存在,若文件存在,則weight權重-10,若文件不存在,則每隔一秒檢測
interval 1 \\每隔一秒檢測
weight -10
fall 2 \\檢測兩次故障則表示節點故障
rise 1 \\檢測一次正常則表示節點正常
}
vrrp_script chk_nginx { \\檢測nginx服務是否運行腳本
script "killall -0 nginx" \\-0為探測信號,當nginx進程存在時,返回值$?=0,當nginx進程不存在時,返回值$?為非零,則權重減10
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_A {
state BACKUP
interface ens33
virtual_router_id 51
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQHuL
}
virtual_ipaddress {
172.16.253.150/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script { \\腳本調用
chk_mant_down
chk_nginx \\調用chk_nginx腳本
}
}
[root@keepalive-A ~]# systemctl start keepalived
[root@keepalive-A ~]# systemctl status keepalived
keepalive-B
[root@keepalive-B ~]# yum -y install keepalived
[root@keepalive-A ~]# vim /etc/keepalived/notify.sh \\定義狀態檢測通知腳本
#!/bin/bash
#
contact='root@localhost' \\通知的聯系者,即本地郵件服務器的通知郵件接受者
notify() {
local mailsubject="$(hostname) to be $1, vip floating" \\指定郵件標題
local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1" \\指定郵件正文
echo "$mailbody" | mail -s "$mailsubject" $contact \\發送通知信息郵件到郵件接收者
}
case $1 in
master)
notify master
;;
backup)
notify backup
systemctl start nginx
;;
fault)
notify fault
;;
*)
echo "Usage: $(basename $0) {master|backup|fault}"
exit 1
;;
esac
[root@keepalive-B ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down { \\定義檢測腳本
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" \\檢測/etc/keepalived/down文件是否存在,若文件存在,則weight權重-10,若文件不存在,則每隔一秒檢測
interval 1 \\每隔一秒檢測
weight -10
fall 2 \\檢測兩次故障則表示節點故障
rise 1 \\檢測一次正常則表示節點正常
}
vrrp_script chk_nginx { \\檢測nginx服務是否運行腳本
script "killall -0 nginx" \\-0為探測信號,當nginx進程存在時,返回值$?=0,當nginx進程不存在時,返回值$?為非零,則權重減10
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_A {
state BACKUP
interface ens33
virtual_router_id 51
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQHuL
}
virtual_ipaddress {
172.16.253.150/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script { \\腳本調用
chk_mant_down
chk_nginx \\調用chk_nginx腳本
}
}
[root@keepalive-B ~]# systemctl start keepalived
[root@keepalive-A ~]# systemctl start keepalived
測試
訪問測試調度
[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
測試檢測監控Nginx服務資源的外部腳本
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
inet 172.16.253.150/32 scope global ens33
valid_lft forever preferred_lft forever
手動停止Nginx服務,keepalive-A變成了BACKUP節點
[root@keepalive-A ~]# systemctl stop nginx
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
幾秒種后,Nginx服務再次自動啟動,則Keepalive-A再次成為MASTER節點
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
inet 172.16.253.150/32 scope global ens33
valid_lft forever preferred_lft forever
當Nginx的80端口占用時,Nginx服務停止之后不會再次啟動,則keepalive-A變為BACKUP
[root@keepalive-A ~]# yum -y install httpd
[root@keepalive-A ~]# systemctl stop nginx && systemctl start httpd \\停止nginx的同時啟動httpd
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
[root@keepalive-A ~]# systemctl status keepalived.service
Sep 05 21:21:14 cxjing.com Keepalived_vrrp[24153]: VRRP_Script(chk_nginx) failed
在HTTP進程停止之后,80端口被釋放,則keepalive-A上的Nginx也不會再次重啟
雙主模式的Nginx調度(一般不會做會話綁定)
雙主模式的目的是為了解決訪問路徑的單點故障,當一個web虛擬路由故障時,可使用另外一個web路徑訪問,最終是實現集群的高可用性
實驗環境
keepalive-A 172.16.253.108
keepalive-B 172.16.253.105
Nginx-A 172.16.253.108
Nginx-B 172.16.253.105
LVS-RS1 172.16.250.127
LVS-RS2 172.16.253.193
VI-A 172.16.253.150
VI-B 172.16.253.140
client 172.16.253.177
環境拓撲圖
實現過程
keepalive-A
[root@keepalive-A ~]# vim /etc/keepalived/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
systemctl start nginx
;;
fault)
notify fault
;;
*)
echo "Usage: $(basename $0) {master|backup|fault}"
exit 1
;;
esac
[root@keepalive-A ~]# systemctl stop keepalived
[root@keepalive-A ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down {
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -10
fall 2
rise 1
}
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_A {
state MASTER
interface ens33
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQHuL
}
virtual_ipaddress {
172.16.253.150/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script {
chk_mant_down
chk_nginx
}
}
vrrp_instance VI_B {
state BACKUP
interface ens33
virtual_router_id 52
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQH99
}
virtual_ipaddress {
172.16.253.140/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script {
chk_mant_down
chk_nginx
}
}
[root@keepalive-A ~]# systemctl start keepalived
keepalive-B
[root@keepalive-A ~]# vim /etc/keepalived/notify.sh
#!/bin/bash
#
contact='root@localhost'
notify() {
local mailsubject="$(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
systemctl start nginx
;;
fault)
notify fault
;;
*)
echo "Usage: $(basename $0) {master|backup|fault}"
exit 1
;;
esac
[root@keepalive-B ~]# systemctl stop keepalived
[root@keepalive-B ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down {
script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -10
fall 2
rise 1
}
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_A {
state BACKUP
interface ens33
virtual_router_id 51
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQHuL
}
virtual_ipaddress {
172.16.253.150/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script {
chk_mant_down
chk_nginx
}
}
vrrp_instance VI_B {
state MASTER
interface ens33
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass qr8hQH99
}
virtual_ipaddress {
172.16.253.140/32
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
track_script {
chk_mant_down
chk_nginx
}
}
[root@keepalive-B ~]# systemctl start keepalived
查看keepalive-A和keepalive-B IP地址,確認虛擬路由配置正確
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
inet 172.16.253.150/32 scope global ens33
valid_lft forever preferred_lft forever
[root@keepalive-B ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0e:47:87 brd ff:ff:ff:ff:ff:ff
inet 172.16.253.140/32 scope global ens33
valid_lft forever preferred_lft forever
測試Nginx調度
[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
[root@client ~]# for i in {1..10};do curl http://172.16.253.140;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>