Nginx相关概念
反向代理
- 反向代理（Reverse Proxy）方式是指以代理服务器来接受internet上的连接请求，然后将请求转发给内部网络上的服务器，并将从服务器上得到的结果返回给internet上请求连接的客户端，此时代理服务器对外就表现为一个服务器。
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负载均衡
- 负载均衡，英文名称为Load Balance，是指建立在现有网络结构之上，并提供了一种廉价有效透明的方法扩展网络设备和服务器的带宽、增加吞吐量、加强网络数据处理能力、提高网络的灵活性和可用性。其原理就是数据流量分摊到多个服务器上执行，减轻每台服务器的压力，多台服务器共同完成工作任务，从而提高了数据的吞吐量。
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Nginx的安装
下载nginx
上传并解压nginx
命令：tar -zxvf nginx-1.8.1.tar.gz -C /usr/local/src
编译nginx
进入到nginx源码目录
cd /usr/local/src/nginx-1.8.1检查安装环境,并指定将来要安装的路径
./configure --prefix=/usr/local/nginx缺包报错
./configure: error: C compiler cc is not found
使用YUM安装缺少的包
yum -y install gcc pcre-devel openssl openssl-devel编译安装
make && make install安装完后测试是否正常：
/usr/loca/nginx/sbin/nginx查看端口是否有ngnix进程监听
netstat -ntlp | grep 80
配置nginx
配置反向代理
- 修改nginx配置文件
vim /usr/local/nginx/conf/nginx.conf
server {
listen 80;
server_name demo.nginx.com; #nginx所在服务器的主机名
#反向代理的配置
location / { #拦截所有请求
root html;
proxy_pass http://192.168.0.21:8080; #这里是代理走向的目标服务器：tomcat
}
}
- 启动配置的tomcat
- 启动nginx
./nginx
- 重启nginx
./nginx -s reload
- 关闭
- 查询nginx主进程号
ps -ef | grep nginx- mark
- 从容停止
kill -QUIT 主进程号 - 快速停止
kill -TERM 主进程号 - 强制停止
kill -9 nginx所有进程 - 若nginx.conf配置了pid文件路径，如果没有，则在logs目录下
- kill -信号类型 '/usr/local/nginx/logs/nginx.pid'
- 查询nginx主进程号
动静分离
#动态资源 index.jsp
location ~ .*\.(jsp|do|action)$ {
proxy_pass http://tomcat-01.itcast.cn:8080;
}
#静态资源
location ~ .*\.(html|js|css|gif|jpg|jpeg|png)$ {
expires 3d;
}
负载均衡
- 在http这个节下面配置一个叫upstream的，后面的名字可以随意取，但是要和location下的proxy_pass http://后的保持一致。
http {
是在http里面的, 已有http, 不是在server里,在server外面
upstream tomcats {
server shizhan02:8080 weight=1;#weight表示权重 数字越大越高
server shizhan03:8080 weight=1;
server shizhan04:8080 weight=1;
}
#卸载server里
location ~ .*\.(jsp|do|action) {
proxy_pass http://tomcats; #tomcats是后面的tomcat服务器组的逻辑组号
}
}
利用keepalived实现高可靠
高可靠概念
-
HA(High Available), 高可用性集群，是保证业务连续性的有效解决方案，一般有两个或两个以上的节点，且分为活动节点及备用节点。
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高可靠软件keepalived
- keepalive是一款可以实现高可靠的软件，通常部署在2台服务器上，分为一主一备。Keepalived可以对本机上的进程进行检测，一旦Master检测出某个进程出现问题，将自己切换成Backup状态，然后通知另外一个节点切换成Master状态。
keepalived安装
- 下载keepalived
- 安装
将keepalived解压到/usr/local/src目录下
tar -zxvf keepalived-1.2.19.tar.gz -C /usr/local/src
进入到/usr/local/src/keepalived-1.2.19目录
cd /usr/local/src/keepalived-1.2.19
开始configure
./configure --prefix=/usr/local/keepalived
#编译并安装
make && make install
将keepalived添加到系统服务中
- 拷贝执行文件
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/ - 将init.d文件拷贝到etc下,加入开机启动项
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived
/etc/init.d/keepalived - 将keepalived文件拷贝到etc下
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ - 创建keepalived文件夹
mkdir -p /etc/keepalived - 将keepalived配置文件拷贝到etc下
cp /usr/local/keepalived/etc/keepalived/keepalived.conf/etc/keepalived/keepalived.conf - 添加可执行权限
chmod +x /etc/init.d/keepalived
以上所有命令一次性执行(绝对路径)：
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/keepalived
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir -p /etc/keepalived
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
chmod +x /etc/init.d/keepalived
chkconfig --add keepalived
chkconfig keepalived on
添加keepalived到开机启动
chkconfig --add keepalived
chkconfig keepalived on
配置keepalived虚拟IP
- 修改配置文件： /etc/keepalived/keepalived.conf
#MASTER节点
global_defs {
}
vrrp_instance VI_1 {
state MASTER #指定A节点为主节点 备用节点上设置为BACKUP即可
interface eth0 #绑定虚拟IP的网络接口
virtual_router_id 51 #VRRP组名，两个节点的设置必须一样，以指明各个节点属于同一VRRP组
priority 100 #主节点的优先级（1-254之间），备用节点必须比主节点优先级低
advert_int 1 #组播信息发送间隔，两个节点设置必须一样
authentication { #设置验证信息，两个节点必须一致
auth_type PASS
auth_pass 1111
}
virtual_ipaddress { #指定虚拟IP, 两个节点设置必须一样
192.168.33.60/24 #如果两个nginx的ip分别是192.168.33.61,,...62，则此处的虚拟ip跟它俩同一个网段即可
}
}
#BACKUP节点
global_defs {
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.33.60/24
}
}
- 分别启动两台机器上的keepalived
- 启动命令：
service keepalived start - 测试：
- 杀掉master上的keepalived进程，你会发现，在slave机器上的eth0网卡多了一个ip地址
- 查看ip地址的命令：
ip addr
配置keepalived心跳检查
- 原理：
- Keepalived并不跟nginx耦合，它俩完全不是一家人
但是keepalived提供一个机制：让用户自定义一个shell脚本去检测用户自己的程序，返回状态给keepalived就可以了
MASTER节点
global_defs {
}
vrrp_script chk_health {
script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
interval 1 #每隔1秒执行上述的脚本，去检查用户的程序ngnix
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 1
priority 100
advert_int 2
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_health
}
virtual_ipaddress {
10.0.0.10/24
}
notify_master "/usr/local/keepalived/sbin/notify.sh master"
notify_backup "/usr/local/keepalived/sbin/notify.sh backup"
notify_fault "/usr/local/keepalived/sbin/notify.sh fault"
}
添加切换通知脚本
vi /usr/local/keepalived/sbin/notify.sh
#!/bin/bash
case "$1" in
master)
/usr/local/nginx/sbin/nginx
exit 0
;;
backup)
/usr/local/nginx/sbin/nginx -s stop
/usr/local/nginx/sbin/nginx
exit 0
;;
fault)
/usr/local/nginx/sbin/nginx -s stop
exit 0
;;
*)
echo 'Usage: notify.sh {master|backup|fault}'
exit 1
;;
esac
添加执行权限
chmod +x /usr/local/keepalived/sbin/notify.sh
global_defs {
}
vrrp_script chk_health {
script "[[ `ps -ef | grep nginx | grep -v grep | wc -l` -ge 2 ]] && exit 0 || exit 1"
interval 1
weight -2
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 1
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_health
}
virtual_ipaddress {
10.0.0.10/24
}
notify_master "/usr/local/keepalived/sbin/notify.sh master"
notify_backup "/usr/local/keepalived/sbin/notify.sh backup"
notify_fault "/usr/local/keepalived/sbin/notify.sh fault"
}
在第二台机器上添加notify.sh脚本
分别在两台机器上启动keepalived
service keepalived start
chkconfig keepalived on
