keepalived+nginx高可用怎麼實現

1.keepalived介紹

keepalived最初是專為lvs負載平衡軟體設計的，用來管理和監控lvs叢集系統中各個服務節點的狀態，後來又加入了實現高可用的vrrp功能。 keepalived除了能夠管理lvs軟體外，還能支援其他服務的高可用解決方案。

keepalived透過vrrp協定實現高可用功能的。 vrrp（virtual router redundancy protocol）虛擬路由冗餘協定。 vrrp出現的目的就是為了解決靜態路由單點故障問題，它能保證當個別節點宕機時，整個網路可以不間斷地運作。

2.keepalived高可用故障轉移原理

keepalived高可用服務之間的故障轉移，是透過vrrp來實現的。在keepalived服務工作時，主master節點會不斷地向備節點發送（多播的方式）心跳訊息，用來告訴備backup節點自己還活著。

　　當主節點發生故障時，無法給備節點發送心跳訊息，如果備節點無法繼續偵測到來自主節點的心跳。就會呼叫自身的接管程序，接管主節點的ip資源和服務。當主節點恢復時，備節點又會釋放主節點故障時自身接管的ip資源和服務，恢復到原來的備用角色

##3.安裝nginx

3.1.主節點（192.168.80.22）

3.1.1.安裝編譯工具與函式庫檔案

yum -y install make zlib zlib-devel gcc-c++ libtool openssl openssl-devel

3.1.2.安裝pcre

#进入目录
cd /usr/local/develop/anginx

#上传安装文件并解压
tar -zxvf pcre-8.38.tar.gz

#进入安装目录
cd pcre-8.38

#检查配置
./configure

#编译、安装
make && make install

#查看pcre版本
pcre-config --version

3.1.3.安裝nginx

#进入目录
cd /usr/local/develop/anginx

#上传安装文件，并解压
tar -zxvf nginx-1.8.1.tar.gz

#进入安装目录
cd nginx-1.8.1

#检查配置
./configure --prefix=/usr/local/develop/anginx/webserver/nginx --with-http_stub_status_module --with-http_ssl_module --with-pcre=/usr/local/develop/anginx/pcre-8.38

#编译安装
make && make install

#查看nginx版本
 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v
--------------------------------------------------------
[root@hadoop02 webserver]# /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v
nginx version: nginx/1.8.1

#配置nginx（检查）
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -t

#nginx管理命令
/usr/local/develop/anginx/webserver/nginx/sbin/nginx       # 启动 nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop       # 停止 nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reload      # 重新载入配置文件
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reopen      # 重启 nginx

3.1.4.nginx基礎設定

vi nginx.conf

#user nobody;
worker_processes 1;

#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;

pid    logs/nginx.pid;


events {
  worker_connections 1024;
}


http {
  include    mime.types;
  default_type application/octet-stream;

  log_format main '$remote_addr - $remote_user [$time_local] "$request" '
           '$status $body_bytes_sent "$http_referer" '
           '"$http_user_agent" "$http_x_forwarded_for"';

  access_log logs/access.log main;

  sendfile    on;
  #tcp_nopush   on;

  #keepalive_timeout 0;
  keepalive_timeout 65;

  #gzip on;

  #添加tomcat列表，真实应用服务器都放在这
  upstream tomcat_pool{
    #server tomcat地址:端口号 weight表示权值，权值越大，被分配的几率越大;
    server 192.168.80.22:8080 weight=4 max_fails=2 fail_timeout=30s;
    server 192.168.80.22:8081 weight=4 max_fails=2 fail_timeout=30s;

  }

  server {
    listen    80;
    server_name tomcat_pool;

    #charset koi8-r;

    #access_log logs/host.access.log main;

    location / {
      #root  html;
      #index index.html index.htm;
      proxy_pass http://tomcat_pool;  #转向tomcat处理
      proxy_set_header  host       $host;
      proxy_set_header  x-real-ip    $remote_addr;
      proxy_set_header  x-forwarded-for $proxy_add_x_forwarded_for;
    }

    #error_page 404       /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page  500 502 503 504 /50x.html;
    location = /50x.html {
      root  html;
    }


}

3.2.備節點（192.168.80.21）

說明：安裝方式同nginx主節點。

4.安裝keepalived

4.1.主節點（192.168.80.22）

#安装keepalived
yum install keepalived -y

#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived：                   [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15723   1 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15724 15723 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15725 15723 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15731 15622 0 00:59 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#

#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local

#关闭keepalived服务
/etc/init.d/keepalived stop

#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf

-----------------------------------------------------------
! configuration file for keepalived

global_defs {
  notification_email {
   acassen@firewall.loc
   failover@firewall.loc
   sysadmin@firewall.loc
  }
  notification_email_from alexandre.cassen@firewall.loc
  smtp_server 192.168.200.1
  smtp_connect_timeout 30
  router_id lb01
}

vrrp_instance vi_1 {
  state master
  interface eth1
  virtual_router_id 55
  priority 150
  advert_int 1
  authentication {
    auth_type pass
    auth_pass server123
  }
  virtual_ipaddress {
    192.168.80.100 dev eth1 label eth1:1
  }
}
...........................................................

關於設定說明：

•  【router_id】 是一個路由標識，在一個區域網路裡面應該是唯一的

• 【vrrp_instance vi_1】{...}這是一個vrrp實例，裡面定義了keepalived的主備狀態、介面、優先權、認證和ip資訊

• 【state】 定義了vrrp的角色

• 【interface】定義使用的接口，這裡我的伺服器用的網卡都是eth1

• 【virtual_router_id】是虛擬路由id標識，一組的keepalived配置中主備都是設定一致

• 【priority】是優先權，數字越大，優先權越大，

• 【auth_type】是認證方式

• 【auth_pass】是認證的密碼

• 【virtual_ipaddress】 ｛...｝定義虛擬ip位址，可以配置多個ip位址，這裡我定義為192.168.80.100，綁定了eth1的網路接口，虛擬接口eth1:1

##4.2.備節點（192.168.80.21 )

<strong>#安装keepalived
yum install keepalived -y

#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived：                   [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15723   1 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15724 15723 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15725 15723 0 00:59 ?    00:00:00 /usr/sbin/keepalived -d
root   15731 15622 0 00:59 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#

#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local

#关闭keepalived服务
/etc/init.d/keepalived stop

#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf

-----------------------------------------------------------------
! configuration file for keepalived

global_defs {
  notification_email {
   acassen@firewall.loc
   failover@firewall.loc
   sysadmin@firewall.loc
  }
  notification_email_from alexandre.cassen@firewall.loc
  smtp_server 192.168.200.1
  smtp_connect_timeout 30
  router_id lb02
}

vrrp_instance vi_1 {
  state backup
  interface eth1
  virtual_router_id 55
  priority 100
  advert_int 1
  authentication {
    auth_type pass
    auth_pass server123
  }
  virtual_ipaddress {
    192.168.80.100 dev eth1 label eth1:1
  }
}
.............................................................</strong>

5.測試

#5.1.啟動主備節點的keepalived服務

<strong>#在节点一执行（192.168.80.22）
/etc/init.d/keepalived start
-------------------------------------
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15788   1 0 01:09 ?    00:00:00 /usr/sbin/keepalived -d
root   15790 15788 0 01:09 ?    00:00:00 /usr/sbin/keepalived -d
root   15791 15788 0 01:09 ?    00:00:00 /usr/sbin/keepalived -d
root   15807 15622 0 01:33 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#


#在节点二执行（192.168.80.21）
/etc/init.d/keepalived start
---------------------------------------
[root@hadoop01 ~]# ps -ef |grep keepalived
root   11542   1 0 01:30 ?    00:00:00 /usr/sbin/keepalived -d
root   11544 11542 0 01:30 ?    00:00:00 /usr/sbin/keepalived -d
root   11545 11542 0 01:30 ?    00:00:00 /usr/sbin/keepalived -d
root   11550 11512 0 01:33 pts/1  00:00:00 grep keepalived
[root@hadoop01 ~]#</strong>

#5.2.透過虛擬ip存取服務

http://192.168.80.100/session-redis-demo/

5.3.停止主節點keepalived服務

#在节点一执行（192.168.80.22）
/etc/init.d/keepalived stop

#观察备节点变化
ip addr
-------------------------------------------
[root@hadoop01 ~]# ip addr
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown
  link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
  inet 127.0.0.1/8 scope host lo
  inet6 ::1/128 scope host
    valid_lft forever preferred_lft forever
2: eth1: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000
  link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
  inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
  inet 192.168.80.100/32 scope global eth1:1
  inet6 fe80::250:56ff:fe38:e546/64 scope link
    valid_lft forever preferred_lft forever
[root@hadoop01 ~]#

5.4.繼續透過虛擬ip存取服務

http://192.168.80.100/session-redis-demo/

6.keepalived nginx整合

#說明：編寫nginx守護腳本，如果nginx服務出現故障，則停止目前節點的keepalived服務。自動切換到備用節點。

6.1.寫nginx守護腳本

<strong>vi nginx_check.sh

--------------------------------------
#!/bin/bash
while true
do
if [ $(netstat -tlnp|grep nginx|wc -l) -ne 1 ]
then
  /etc/init.d/keepalived stop
fi
sleep 2
done

#给脚本授权
chmod u+x nginx_check.sh

#执行脚本
nohup /usr/local/develop/anginx/shell/nginx_check.sh &</strong>

6.2.停止主節點nginx服務

<strong>#停止主节点nginx服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop

#查找进程
[root@hadoop02 ~]# ps -ef |grep nginx
root   15915   1 0 01:51 ?    00:00:00 /bin/bash /usr/local/develop/anginx/shell/nginx_check.sh
root   16516 15753 0 01:54 pts/5  00:00:00 grep nginx
[root@hadoop02 ~]#

#观察备用节点变化【服务正常】
ip addr
--------------------------------------
[root@hadoop01 shell]# ip addr
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown
  link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
  inet 127.0.0.1/8 scope host lo
  inet6 ::1/128 scope host
    valid_lft forever preferred_lft forever
2: eth1: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000
  link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
  inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
  inet 192.168.80.100/32 scope global eth1:1
  inet6 fe80::250:56ff:fe38:e546/64 scope link
    valid_lft forever preferred_lft forever
[root@hadoop01 shell]#

#再次重新启动主节点nginx和keepalived服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx

/etc/init.d/keepalived start</strong>

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