Nginx+keepalived双机热备
一、nginx简介Nginx是一款轻量级的Web 服务器/反向代理服务器及电子邮件（IMAP/POP3）代理服务器，并在一个BSD-like 协议下发行。其特点是占有内存少，并发能力强，事实上nginx的并发能力确实在同类型的网页服务器中表现较好，中国大陆使用nginx网站用户有：百度、京东、新浪、网易、腾讯、淘宝等。
二、测试环境
下面拿2台虚拟机进行环境测试,实验环境为centos6.6 x86_64,具体用途和ip如下
服务器类型
IP地址
Keepalivedvip
192.168.214.70
Nginx1
192.168.214.76
Nginx2
192.168.214.77
三、安装nginx
这边给大家使用源码包来安装nginx
groupadd nginx
useradd -g nginx -s /sbin/nologin nginx
mkdir /var/log/nginx&&chown -R nginx:nginx /var/log/nginx
mkdir /usr/local/www&&chown -R nginx:nginx /usr/local/www
安装nginx所需pcre库
wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.38.tar.gz
tar zxvf pcre-8.38.tar.gz
cd pcre-8.38
./configure
make && make install
wget http://nginx.org/download/nginx-1.14.0.tar.gz
cd nginx-1.14.0
./configure --prefix=/usr/local/nginx--user=nginx --group=nginx \
--with-http_ssl_module \
--with-http_stub_status_module \
--with-http_flv_module\
--with-http_gzip_static_module
make && make install
ln -s /usr/local/lib/libpcre.so.1 /lib64
使用/usr/local/nginx/sbin/nginx来启动nginx服务
访问下默认nginx页面
四、修改linux文件句柄数
使用ulimit -a查看默认为1024
open files (-n) 1024
1、直接在终端修改 ulimit -SHn 65535
2、修改linux系统参数
vi /etc/security/limits.conf 添加保存后，重启机器就永久生效了
* soft nofile 65535
* hard nofile 65535
五、配置nginx
这边给大家提供了一个最简单的配置文件给大家参考
cat /usr/local/nginx/conf/nginx.conf
usernginx nginx;
worker_processes8;
error_loglogs/error.log;
#error_loglogs/error.lognotice;
#error_loglogs/error.loginfo;
pid /usr/local/nginx/nginx.pid;
worker_rlimit_nofile 65535;
events {
use epoll;
worker_connections65535;
}
http {
include mime.types;
default_typeapplication/octet-stream;
#charset gb2312;
server_names_hash_bucket_size 128;
client_header_buffer_size 32k;
large_client_header_buffers 4 32k;
client_max_body_size 8m;
#log_formatmain'$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_loglogs/access.logmain;
sendfile on;
tcp_nopush on;
#keepalive_timeout0;
keepalive_timeout60;
tcp_nodelay on;
gzipon;
gzip_min_length 1k;
gzip_buffers 4 16k;
gzip_http_version 1.0;
gzip_comp_level 2;
gzip_types text/plain application/x-javascript text/css application/xml;
gzip_vary on;
server {
listen 80;
server_name192.168.214.76;
index index.html index.htm;
root /usr/local/www;
#charset koi8-r;
location /nginx_status {
stub_status on;
access_log off;
}
access_log/var/log/nginx/$server_name.logcombined;
}
}
六、安装keepalived
yum install -y keepalived
chkconfig keepalived on
注：在centos7系列系统中开机自动启动使用systemctl enable keepalived
七、keepalived文件配置
查看192.168.214.76主keepalived配置
cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
charles@test.com
}
notification_email_from info@test.com
smtp_server mail.test.com
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "/usr/local/scripts/nginx_pid.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_interface {
eth0
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.214.70
}
}
查看192.168.214.77备的keepalived配置
! Configuration File for keepalived
global_defs {
notification_email {
charles@test.com
}
notification_email_from info@test.com
smtp_server mail.test.com
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "/usr/local/scripts/nginx_pid.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_interface {
eth0
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.214.70
}
}
最后附上Nginx的检测脚本，当主服务器探测到nginx服务停止后，尝试开启nginx服务，失败后关闭主服务器的keepalived服务，把vip切换到备上
cat nginx_pid.sh
#!/bin/bash
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ];then
/usr/local/nginx/sbin/nginx
sleep 3
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
killall keepalived
fi
fi
八、启动keepalived服务及查看相关信息
在192.168.214.76上通过ip addr 查看，vip192.168.214.70已经绑定在eth0网口上了
# ip addr
1: lo:mtu65536 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: eth0: mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 52:54:00:55:b2:d4 brd ff:ff:ff:ff:ff:ff
inet 192.168.214.76/24 brd 192.168.214.255 scope global eth0
inet 192.168.214.70/32 scope global eth0
inet6 fe80::5054:ff:fe55:b2d4/64 scope link
valid_lft forever preferred_lft forever
3: eth1: mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 52:54:00:85:11:95 brd ff:ff:ff:ff:ff:ff
inet 192.168.211.76/24 brd 192.168.211.255 scope global eth1
inet6 fe80::5054:ff:fe85:1195/64 scope link
valid_lft forever preferred_lft forever
在214.76上查看日志信息，看到已成功进入keepalived主机模式
# tail -f/var/log/messages
May 17 16:29:00 localhostKeepalived_healthcheckers: Registering Kernel netlink command channel
May 17 16:29:00 localhostKeepalived_healthcheckers: Opening file '/etc/keepalived/keepalived.conf'.
May 17 16:29:00 localhostKeepalived_healthcheckers: Configuration is using : 7681 Bytes
May 17 16:29:00 localhostKeepalived_healthcheckers: Using LinkWatch kernel netlink reflector...
May 17 16:29:01 localhost Keepalived_vrrp:VRRP_Instance(VI_1) Transition to MASTER STATE
May 17 16:29:02 localhostKeepalived_vrrp: VRRP_Instance(VI_1) EnteringMASTER STATE
May 17 16:29:02 localhostKeepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
May 17 16:29:02 localhostKeepalived_vrrp: VRRP_Instance(VI_1) Sendinggratuitous ARPs on eth0 for 192.168.214.70
May 17 16:29:02 localhostKeepalived_healthcheckers: Netlink reflector reports IP 192.168.214.70 added
May 17 16:29:07 localhost Keepalived_vrrp:VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.214.70
在214.77上查看日志信息，看到已成功进入keepalived备机模式
May 17 16:29:06 localhostKeepalived_vrrp: Opening file '/etc/keepalived/keepalived.conf'.
May 17 16:29:06 localhost Keepalived_vrrp:Configuration is using : 66478 Bytes
May 17 16:29:06 localhostKeepalived_vrrp: Using LinkWatch kernel netlink reflector...
May 17 16:29:06 localhostKeepalived_vrrp: VRRP_Instance(VI_1) EnteringBACKUP STATE
May 17 16:29:06 localhostKeepalived_vrrp: VRRP sockpool:
May 17 16:29:06 localhostKeepalived_healthcheckers: Using LinkWatch kernel netlink reflector...
九、keepalived测试
使用vip192.168.214.70访问nginx
最后，我们模拟下192.168.214.76nginx服务宕机，且无法通过脚本恢复，看下vip地址是否会漂移过去，nginx页面是否能正常访问。
通过ip addr命令看到vip已漂移到了192.168.214.77nginx服务器上，成功实现了热备。
# ip addr
1: lo:mtu65536 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: eth0: mtu 1500 qdisc pfifo_fast state UP qlen1000
link/ether 52:54:00:1b:a2:11 brd ff:ff:ff:ff:ff:ff
inet 192.168.214.77/24 brd 192.168.214.255 scope global eth0
inet 192.168.214.70/32 scope global eth0
inet6 fe80::5054:ff:fe1b:a211/64 scope link
valid_lft forever preferred_lft forever
3: eth1: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 52:54:00:64:47:7d brd ff:ff:ff:ff:ff:ff
inet 192.168.211.77/24 brd 192.168.211.255 scope global eth1
inet6 fe80::5054:ff:fe64:477d/64 scope link
valid_lft forever preferred_lft forever
在214.77上查看日志信息，看到从之前的备机模式已成功进入keepalived主机模式
# tail -f/var/log/messages
May 17 16:29:06 localhostKeepalived_vrrp: Using LinkWatch kernel netlink reflector...
May 17 16:29:06 localhost Keepalived_vrrp:VRRP_Instance(VI_1) Entering BACKUP STATE
May 17 16:29:06 localhostKeepalived_vrrp: VRRP sockpool:
May 17 16:29:06 localhostKeepalived_healthcheckers: Using LinkWatch kernel netlink reflector...
May 17 16:49:47 localhostKeepalived_vrrp: VRRP_Instance(VI_1) Transitionto MASTER STATE
May 17 16:49:48 localhostKeepalived_vrrp: VRRP_Instance(VI_1) EnteringMASTER STATE
May 17 16:49:48 localhostKeepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
May 17 16:49:48 localhostKeepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for192.168.214.70
May 17 16:49:48 localhostKeepalived_healthcheckers: Netlink reflector reports IP 192.168.214.70added
May 17 16:49:53 localhostKeepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for192.168.214.70
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