Nginx+keepalived雙機熱備(主主模式)
Nginx+keepalived實現高可用負載均衡的主主模式
由於網站的訪問需求不斷加大,負載越來越高。現需要在web前端放置nginx負載均衡,同時結合keepalived對前端nginx實現HA高可用。
1、nginx進程基於Master+Slave(worker模式)多進程模型,自身具有非常穩定的子進程管理功能。在Master進程分配模式下,Master進程永遠不進行業務處理,只是進行任務分發,從而達到Master進程的存活高可靠性,Slave(worker)進程所有的業務信號都由主進程發出,Slave(worker)進程所有的超時任務都會被Master中止,屬於非阻塞式任務模型。
2、Keepalived是Linux下面實現VRRP備份路由的高可靠性運行件。基於Keepalived設計的服務模式能夠真正做到主服務器和備份服務器故障時IP瞬間無縫交接。二者結合,可以構架出比較穩定的軟件LB方案。
雙機高可用方法目前分為兩種:
1)雙機主從模式:即前端使用兩臺服務器,一臺主服務器和一臺熱備服務器,正常情況下,主服務器綁定一個公網虛擬IP,提供負載均衡服務,熱備服務器處於空閑狀態;當主服務器發生故障時,熱備服務器接管主服務器的公網虛擬IP,提供負載均衡服務;但是熱備服務器在主機器不出現故障的時候,永遠處於浪費狀態,對於服務器不多的網站,該方案不經濟實惠。
2)雙機主主模式:這種模式的效果很強大,即前端使用兩臺負載均衡服務器,互為主備,且都處於活動狀態(這樣達到不浪費服務器),同時各自綁定一個公網虛擬IP,提供負載均衡服務;當其中一臺發生故障時,另一臺接管發生故障服務器的公網虛擬IP(這時由非故障機器一臺負擔所有的請求)。這種方案,經濟實惠,非常適合於當前架構環境。
一、環境介紹:
操作系統:
[root@centos-4 ~]# cat /etc/redhat-release
CentOS release 6.9 (Final)
服務器對應關系:
KA1:192.168.5.129 centos-1
KA2:192.168.5.128 centos-4
Vip1:192.168.5.200 129master/128backup
VIP2:192.168.5.210 128master/129backup
Web1:192.168.5.131 centos-2
Web2:192.168.5.132 centos-3
二、環境安裝:
安裝依賴:
(在KA1和KA2機器上執行以下步驟)
[root@centos-4 ~]# yum -y install gcc pcre-devel zlib-devel openssl-devel
[root@centos-4~]# cd /usr/local/src/
[root@centos-4 src]# wget http://nginx.org/download/nginx-1.9.7.tar.gz
安裝nginx
[root@centos-4 src]# tar -zvxfnginx-1.9.7.tar.gz
[root@centos-4 src]# cd nginx-1.9.7
[root@centos-4 nginx-1.9.7]#./configure --prefix=/usr/local/nginx --user=nginx --group=nginx--with-http_ssl_module --with-http_flv_module --with-http_stub_status_module--with-http_gzip_static_module --with-pcre
[root@centos-4 nginx-1.9.7]# make &&make install
[root@centos-1 ~]# yum install -ykeepalived
(在web1服務器和web2服務器上安裝nginx)
[root@centos-2~]# yum -y install gcc pcre-devel zlib-devel openssl-devel
[root@centos-2~]# cd /usr/local/src/
[root@centos-2 src]# wget http://nginx.org/download/nginx-1.9.7.tar.gz
安裝nginx
[root@centos-2 src]# tar -zvxfnginx-1.9.7.tar.gz
[root@centos-2 src]# cd nginx-1.9.7
[root@centos-2 nginx-1.9.7]# ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx--with-http_ssl_module --with-http_flv_module --with-http_stub_status_module--with-http_gzip_static_module --with-pcre
[root@centos-2 nginx-1.9.7]# make &&make install
三、配置服務:
(所以服務器上配置)
[root@centos-1 ~]# cat/etc/sysconfig/selinux
SELINUX=disabled
[root@centos-1 ~]# getenforce
Disabled
[root@centos-1 ~]# service iptables stop
1、配置keepalived:
(KA1上操作)
[root@centos-1 ~]#cat /etc/keepalived/keepalived.conf ! Configuration Filefor keepalived global_defs { notification_email { [email protected] #[email protected] #[email protected] } router_id LVS_DEVEL } vrrp_scriptchk_http_port { script "/opt/check_nginx.sh" interval 2 weight -5 fall 2 rise 1 } vrrp_instance VI_1{ state MASTER interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.5.200 } } vrrp_instance VI_2{ state BACKUP interface eth0 virtual_router_id 50 priority 90 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.5.210 } track_script { chk_http_port } }
(KA2上操作)
[root@centos-2 ~]#cat /etc/keepalived/keepalived.conf ! Configuration Filefor keepalived global_defs { notification_email { [email protected] #[email protected] #[email protected] } router_id LVS_DEVEL } vrrp_scriptchk_http_port { script "/opt/check_nginx.sh" interval 2 weight -5 fall 2 rise 1 } vrrp_instance VI_1{ state BACKUP interface eth0 virtual_router_id 51 priority 90 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.5.200 } } vrrp_instance VI_2{ state MASTER interface eth0 virtual_router_id 50 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.5.210 } track_script { chk_http_port } }
編寫一個監控nginx的腳本:
需要註意的是,要判斷本機nginx是否正常,如果發現nginx不正常,重啟之後,等待三秒在校驗,任然失敗則不嘗試,關閉keepalived,發送郵件,其他主機此時接管VIP;
[root@centos-4~]# cat /opt/check_nginx.sh #!/bin/bash check=$(ps-C nginx --no-heading|wc -l) IP=`ipadd | grep eth0 | awk ‘NR==2{print $2}‘| awk -F ‘/‘ ‘{print $1}‘` if ["${check}" = "0" ]; then /usr/local/nginx/sbin/nginx sleep 2 counter=$(ps -C nginx --no-heading|wc -l) if [ "${check}" = "0"]; then /etc/init.d/keepalived stop echo "check $IP nginx is down"| mail -s "check keepalived nginx" *********@qq.com fi fi
(KA1一樣的監控腳本)
2、在兩臺前端服務器上啟動keepalived服務,對於192.168.5.200的vip centos-1是master/192.168.5.210的vip centos-1是backup。
[root@centos-1 ~]#service keepalived start
[root@centos-4 ~]# service keepalived start
查看日誌文件:
[root@centos-1 ~]# cat /var/log/messages
Oct 19 22:00:22 centos-1 Keepalived_vrrp[46184]: VRRP_Instance(VI_2)Sending gratuitous ARPs on eth0 for 192.168.5.210
Oct 19 22:00:22 centos-1 Keepalived_healthcheckers[46183]: Netlinkreflector reports IP 192.168.5.210 added
Oct 19 22:00:24 centos-1 Keepalived_vrrp[46184]: VRRP_Instance(VI_1)Sending gratuitous ARPs on eth0 for 192.168.5.200
Oct 19 22:00:27 centos-1 Keepalived_vrrp[46184]: VRRP_Instance(VI_2)Sending gratuitous ARPs on eth0 for 192.168.5.210
(因為KA1先啟動keepalived服務所以兩個vip都會在KA1上,但第二臺keepaliver服務起來後vip2就會被KA2搶占回來。)
[root@centos-4 ~]# cat /var/log/messages
Oct 19 22:01:38 centos-4 Keepalived_healthcheckers[15009]: Netlinkreflector reports IP 192.168.5.210 added
Oct 19 22:01:38 centos-4 avahi-daemon[1513]: Registering new addressrecord for 192.168.5.210 on eth0.IPv4.
Oct 19 22:01:38 centos-4 Keepalived_vrrp[15010]: VRRP_Instance(VI_2)Sending gratuitous ARPs on eth0 for 192.168.5.210
Oct 19 22:01:43 centos-4 Keepalived_vrrp[15010]: VRRP_Instance(VI_2)Sending gratuitous ARPs on eth0 for 192.168.5.210
查看ip addr:
[root@centos-1 keepalived]# ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_faststate UP qlen 1000
link/ether00:0c:29:0d:f3:5d brd ff:ff:ff:ff:ff:ff
inet 192.168.5.129/24 brd192.168.5.255 scope global eth0
inet 192.168.5.200/32scope global eth0
[root@centos-4 keepalived]#ip addr
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdiscpfifo_fast state UP qlen 1000
link/ether00:50:56:3a:84:30 brd ff:ff:ff:ff:ff:ff
inet 192.168.5.128/24 brd192.168.5.255 scope global eth0
inet 192.168.5.210/32 scope global eth0
3、配置nginx的反向代理
(在web1和web2服務器上配置兩個web服務(可以http或者nginx)用來測試使用,這裏就不一一演示了。)
[root@centos-2 ~]# curl localhost
2
[root@centos-3 ~]# curl localhost
3
(在兩臺前端服務器上配置)
[root@centos-1 ~]# vim/usr/local/nginx/conf/nginx.conf …… …… …… upstreambackend { ip_hash; server 192.168.5.131:80 max_fails=2fail_timeout=30s; server 192.168.5.132:80 max_fails=2fail_timeout=30s; #ip_hash: 每個請求按訪問ip的hash結果分配,這樣每個訪客固定訪問一個後端服務器,可以解決session的問題。 #max_fails=2 為允許失敗的次數,默認值為1 #fail_timeout=30s 當max_fails次失敗後,暫停將請求分發到該後端服務器的時間 } proxy_temp_path /usr/local/nginx/cache/tmp 1 2; proxy_cache_path /usr/local/nginx/cache levels=1:2 keys_zone=cache1:100m inactive=1dmax_size=10g; …… …… …… server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { proxy_pass http://backend; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_cache cache1; add_header X-Cache$upstream_cache_status; proxy_cache_key $host$uri$is_args$args; proxy_cache_valid 200 304 10m; expires 30d; # root /web; index index.php index.html index.htm; }
[root@centos-2 ~]# vim/usr/local/nginx/conf/nginx.conf …… …… …… upstreambackend { ip_hash; server 192.168.5.131:80 max_fails=2fail_timeout=30s; server 192.168.5.132:80 max_fails=2fail_timeout=30s; } proxy_temp_path /usr/local/nginx/cache/tmp 1 2; proxy_cache_path /usr/local/nginx/cache levels=1:2 keys_zone=cache1:100m inactive=1dmax_size=10g; …… …… …… server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { proxy_pass http://backend; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_cache cache1; add_header X-Cache$upstream_cache_status; proxy_cache_key $host$uri$is_args$args; proxy_cache_valid 200 304 10m; expires 30d; # root /web; index index.php index.html index.htm; }
(兩臺KA1和KA2服務器重啟nginx、keepalived服務)
[root@centos-1~]# /usr/local/nginx/sbin/nginx -t
nginx:the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx:configuration file /usr/local/nginx/conf/nginx.conf test is successful ###檢查配置文件沒問題後再執行重啟nginx。
[root@centos-1~]# /usr/local/nginx/sbin/nginx -s reload
[root@centos-4~]# /usr/local/nginx/sbin/nginx -t
nginx:the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx:configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@centos-4~]# /usr/local/nginx/sbin/nginx -s reload
[root@centos-1~]# service keepalived restart
停止keepalived: [確定]
正在啟動keepalived: [確定]
[root@centos-4~]# service keepalived restart
停止keepalived: [確定]
正在啟動keepalived: [確定]
四、測試:
驗證方法(保證從負載均衡器本機到後端真實服務器之間能正常通信):
(1)、先測試完成後的效果訪問vip1、vip2
[root@centos-1 ~]# curl 192.168.5.200
10.2
[root@centos-1 ~]# curl 192.168.5.210
10.3
(註意在KA1、KA2上做了緩存和ip_hash)
(2)、把KA1keepalived stop掉(模擬KA1主機的keepalived故障)
[root@centos-1 ~]# service keepalived stop
停止 keepalived:
[root@centos-1 ~]# ip addr
2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 00:0c:29:0d:f3:5d brd ff:ff:ff:ff:ff:ff
inet 192.168.5.129/24 brd 192.168.5.255 scope global eth0
inet6 fe80::20c:29ff:fe0d:f35d/64 scope link
valid_lft forever preferred_lft forever
(KA1主機上查看ip addr已經沒有vip了。)
在KA2主機上查看日誌文件:
[root@centos-4 ~]# cat /var/log/messages
Oct 19 23:20:46 centos-4Keepalived_vrrp[15412]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for192.168.5.200
Oct 19 23:20:46 centos-4avahi-daemon[1513]: Registering new address record for 192.168.5.200 oneth0.IPv4.
Oct 19 23:20:46 centos-4 Keepalived_healthcheckers[15411]:Netlink reflector reports IP 192.168.5.200 added
Oct 19 23:20:51 centos-4Keepalived_vrrp[15412]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for192.168.5.200
(日誌文件顯示已經把vip:192.168.5.200接管了)
查看KA2主機的ip addr
[root@centos-4 ~]# ip addr
2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 00:50:56:3a:84:30 brd ff:ff:ff:ff:ff:ff
inet 192.168.5.128/24 brd 192.168.5.255 scope global eth0
inet 192.168.5.210/32 scope global eth0
inet 192.168.5.200/32 scope global eth0
(可以看到已經有兩個vip)
檢查nginx服務是否被KA2接管且不中斷
[root@centos-1 ~]# curl 192.168.5.210
10.3
[root@centos-1 ~]# curl 192.168.5.200
10.2
(可以看到服務還是進行的而且緩存還在。ip_hash的作用)
本文出自 “第一個legehappy51cto博客” 博客,請務必保留此出處http://legehappy.blog.51cto.com/13251607/1974468
Nginx+keepalived雙機熱備(主主模式)