Nginx+Keepalived 主備高可用 安裝與配置

環境說明：
作業系統：CentOS6.7 x86_64
Nginx版本：nginx-1.9.7
Keepalived版本：keepalived-1.2.24 
主nginx + Keepalived ：10.219.24.26
備nginx + Keepalived ：10.219.24.23
虛擬IP：10.219.24.100
後端tomcat_1：10.219.24.21:8080
後端tomcat_2：10.219.24.21:8081

架構與原理： 前端雙 Nginx + Keepalived ，Nginx反向代理到後端tomcat叢集實現負載均衡，Keepalived實現叢集高可用，
主nginx故障後虛擬IP自動漂移到備nginx。

一、 Nginx + Keepalived 安裝

一、1 nginx-1.9.7 編譯安裝

下載地址:

補充: 安裝 nginx之前，需要先安裝一些依賴包：gcc、pcre、zlib
a、nginx gzip模組需要zlib庫
b、nginx rewrite模組需要pcre庫
c、nginx ssl模組需要openssl庫

1、安裝必要依賴包
[root@mysql03 ~]# yum install -y pcre pcre-devel

centos 6.7 配置 yum 本地源 連結參考： http://blog.csdn.NET/zhang123456456/article/details/56690945 
2、 Nginx安裝
[root@mysql03 ~]# ll nginx-1.9.7.tar.gz 
-rw-r--r--. 1 root root 885562 Jun 14 21:46 nginx-1.9.7.tar.gz
[root@mysql03 ~]# tar zxvf nginx-1.9.7.tar.gz
[root@mysql03 ~]# cd nginx-1.9.7
-- 配置nginx安裝選項
[root@mysql03 nginx-1.9.7]# ./configure --prefix=/usr/local/nginx
說明： 配置完畢後可以看到一個配置概要，概要中的5項必須都有了相應的庫支援
Configuration summary
+ using system PCRE library
+ OpenSSL library is not used 
##如果想要安裝openssl模組，安裝時需指定 ./configure --prefix=/usr/local/nginx --with-openssl=/root/openssl-1.0.2d ## 
+ md5: using system crypto library
+ sha1: using system crypto library
+ using system zlib library
-- 安裝nginx
[root@mysql03 nginx-1.9.7]# make && make install
3、 檢查安裝是否正常
[root@mysql03 nginx-1.9.7]# cd /usr/local/nginx
[root@mysql03 nginx]# ll
total 16
drwxr-xr-x. 2 root root 4096 Jun 14 22:14 conf
drwxr-xr-x. 2 root root 4096 Jun 14 22:14 html
drwxr-xr-x. 2 root root 4096 Jun 14 22:14 logs
drwxr-xr-x. 2 root root 4096 Jun 14 22:14 sbin
-- 啟動
[root@mysql03 nginx]# ./sbin/nginx #如果不能正常啟動，可能是埠占用 
[root@mysql03 nginx]# ps -ef|grep nginx
root 5212 1 0 22:17 ? 00:00:00 nginx: master process ./sbin/nginx
nobody 5213 5212 0 22:17 ? 00:00:00 nginx: worker process
root 5228 2359 0 22:20 pts/0 00:00:00 grep nginx
-- 訪問
瀏覽器輸入： #ip換成自己的ip 
看到以下頁面內容，一切正常。
Welcome to nginx!

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.

Thank you for using nginx.

-- 關閉
[root@mysql03 nginx]# ./sbin/nginx -s stop
[root@mysql03 nginx]# ps -ef|grep nginx
root 5241 2359 0 22:25 pts/0 00:00:00 grep nginx

一、2 安裝 keepalived-1.2.24

一、2.1 安裝 LVS

前提：已經提前配置好本地 Yum 源 配置過程可參考> http://blog.csdn.NET/zhang123456456/article/details/56690945
1、 檢查一下系統核心
安裝之前，首先檢查一下系統核心是否支援LVS的IPVS模組；自Linux 2.6開始，系統核心完全內建了LVS的各個模組。
[root@mysql03 ~]# modprobe -l|grep ipvs
kernel/net/netfilter/ipvs/ip_vs.ko
kernel/net/netfilter/ipvs/ip_vs_rr.ko
kernel/net/netfilter/ipvs/ip_vs_wrr.ko
kernel/net/netfilter/ipvs/ip_vs_lc.ko
....
kernel/net/netfilter/ipvs/ip_vs_pe_sip.ko
看到如上輸出資訊，則表明系統核心預設支援IPVS模組。

2、安裝依賴包
由於是原始碼包安裝，所以編譯時需要打上如下依賴包。
# yum -y install kernel-headers glibc-headers glibc-devel libgomp gcc libstdc++-devel gcc-c++

3、 yum安裝 ipvsadm-1.26-4 
[root@mysql03 ~]# yum -y install kernel-devel ipvsadm
===================================================================================
Package Arch Version Repository Size
===================================================================================
Installing:
ipvsadm x86_64 1.26-4.el6 c6-media 42 k

Transaction Summary
===================================================================================
Install 1 Package(s)

Total download size: 42 k
Installed size: 78 k
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : ipvsadm-1.26-4.el6.x86_64 1/1 
Verifying : ipvsadm-1.26-4.el6.x86_64 1/1

Installed:
ipvsadm.x86_64 0:1.26-4.el6

Complete!
4、 做個 ln
[root@mysql03 ~]# ln -sv /usr/src/kernels/2.6.32-573.el6.x86_64/ /usr/src/linux <--請自行修改 kernels 版本號

5、 檢視 ipvsadm 版本資訊
[root@mysql03 ~]# ipvsadm -version
ipvsadm v1.26 2008/5/15 (compiled with popt and IPVS v1.2.1) #> 能看到幫助資訊，則說明IPVS安裝成功。

一、2.2 安裝 keepalived-1.2.24

1、官網下載地址：
[root@mysql03 ~]# wget
2、解壓安裝包：
[root@mysql03 ~]# ll keepalived-1.2.24.tar.gz 
-rw-r--r--. 1 root root 601873 Jun 16 23:49 keepalived-1.2.24.tar.gz
[root@mysql03 ~]# tar -zxvf keepalived-1.2.24.tar.gz
3、進入安裝目錄：
[root@mysql03 ~]# cd keepalived-1.2.24

4、安裝keepalived:
[root@mysql03 keepalived-1.2.24]# ./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.32-573.el6.x86_64/

說明：--with-kernel-dri ：指定使用核心原始碼中的標頭檔案，即include目錄，該引數很重要，只有使用LVS時才用此引數。
主要輸出：
Keepalived configuration
------------------------
Keepalived version : 1.2.24
Compiler : gcc
Preprocessor flags : 
Compiler flags : -Wall -Wunused -Wstrict-prototypes
Linker flags : 
Extra Lib : -ldl -lssl -lcrypto 
Use IPVS Framework : Yes
IPVS use libnl : No
IPVS syncd attributes : No
IPVS 64 bit stats : No
fwmark socket support : Yes
Use VRRP Framework : Yes
Use VRRP VMAC : Yes
Use VRRP authentication : Yes
With ip rules/routes : Yes
SNMP keepalived support : No
SNMP checker support : No
SNMP RFCv2 support : No
SNMP RFCv3 support : No
SHA1 support : No
Use Debug flags : No
Stacktrace support : No
Memory alloc check : No
libnl version : None
Use IPv4 devconf : No
Use libiptc : No
Use libipset : No
Build genhash : Yes
Build documentation : No
[root@mysql03 keepalived-1.2.24]# make && make install

5、複製指令碼和檔案：

5.1 複製執行檔案
[root@mysql03 keepalived-1.2.24]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
5.2 將init.d檔案複製到etc下,加入開機啟動項
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
5.3 將keepalived檔案複製到etc下，加入網路卡配置
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
5.4 建立keepalived資料夾
[root@node6 keepalived-1.2.16]# mkdir /etc/keepalived
5.5 將keepalived配置檔案複製到etc下
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
5.6 複製啟動指令碼
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/sbin/keepalived /etc/keepalived/

6、加入開機啟動項
[root@mysql03 keepalived-1.2.24]# chkconfig --add keepalived #新增時必須保證/etc/init.d/keepalived存在
7、 啟動
[root@mysql03 keepalived-1.2.24]# service keepalived start
Starting keepalived: [ OK ]
8、 關閉
[root@mysql03 keepalived-1.2.24]# service keepalived stop
Stopping keepalived: [ OK ] > OK，成功！

說明： 安裝完 主nginx + Keepalived 後， 同理安裝 備nginx + Keepalived 。 

二、 Nginx + Keepalived 配置

1. 主 nginx /usr/local/nginx/conf/nginx.conf 配置
[root@mysql03 ~]# vi /usr/local/nginx/conf/nginx.conf
[root@mysql03 nginx]# cat /usr/local/nginx/conf/nginx.conf
user root root;
worker_processes 1;

events {
worker_connections 1024;
}

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

upstream web_app {
server 10.219.24.21:8080 weight=1 max_fails=2 fail_timeout=30s;
server 10.219.24.21:8081 weight=1 max_fails=2 fail_timeout=30s; 
}

server {
listen 80;
server_name aa.com;
charset utf8;
location / {
proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
proxy_pass
proxy_redirect default; 
}
}
}

說明： 配置完 主 nginx後 ， 同理 ， 配置 備 nginx

2. 主 nginx 的keepalived 配置
[root@mysql03 nginx]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
router_id nginx-ha1
}

vrrp_script check_nginx {
# 檢查nginx狀態的指令碼
script "/data/script/check_nginx.sh"
interval 2
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.219.24.100
}
track_script {
check_nginx
}
}

3. 備 nginx 的 keepalived 配置
[root@redis01 ~]# vi /etc/keepalived/keepalived.conf
[root@redis01 ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
router_id nginx-ha2
}

vrrp_script check_nginx {
script "/data/script/check_nginx.sh"
interval 2
}

vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 80
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.219.24.100
}
track_script {
check_nginx
}
}

補充: 如果開了防火牆，則還需進行防火牆設定，如果沒有防火牆設定，則可忽略
# iptables放行組播地址流量:
iptables -I INPUT -d 224.0.0.18 -j ACCEPT
service iptables save

4. 部署nginx狀態檢查指令碼check_nginx.sh

4.1 檢查nc是否安裝 ， 沒有安裝nc包 ，要進行 yum -y install nc 安裝 ， 不然指令碼 check_nginx.sh 中 nc命令用不了。
[root@mysql03 ~]# rpm -q nc 
nc-1.84-24.el6.x86_64

4.2 建立指令碼目錄
[root@mysql03 ~]# mkdir -p /data/script/
[root@mysql03 ~]# touch /data/script/check_nginx.sh
[root@mysql03 ~]# cat /data/script/check_nginx.sh
#!/bin/bash
# check nginx server status
# nginx埠，如果有兩個埠，只需要設定為 PORTS="80 81",則下面也應改為"$ret1" != 11
PORTS="80"

function check_ports {
for port in $PORTS;do
nc -z 127.0.0.1 $port | grep -q succeeded
[ "${PIPESTATUS[1]}" -eq 0 ] && mark=${mark}1
done
# 如果mark值為空說明埠都不通。
# 如果mark等於1，說明有埠是通的。
echo $mark
}

ret1=$(check_ports)
# 如果nginx埠不通，會嘗試重啟一次nginx
if [ "$ret1" != 1 ];then
/sbin/service nginx stop
/sbin/service nginx start
sleep 1
ret2=$(check_ports)
# 如果還是有埠不通，表示nginx服務不正常，則停掉keepalived，使VIP發生切換
[ "$ret2" != 1 ] && /etc/init.d/keepalived stop
fi

5. 給指令碼設定可執行許可權：
[root@mysql03 ~]# chmod +x /data/script/check_nginx.sh

說明： 4. 5.操作都在主、備上都操作

補充一點：
如果nginx恢復正常後，keepalived不能自動啟動，需要編寫一個指令碼完成這項工作：判斷nginx正常後，拉起keepalived。
指令碼放到cron裡每分鐘執行。

6. 開啟keepalived的日誌 （keepalived預設的日誌位置為 /var/log/messages ，最好我們將它單獨放置）
6.1 編輯 /etc/sysconfig/keepalived 將 KEEPALIVED_OPTIONS="-D" 改為 KEEPALIVED_OPTIONS="-D -d -S 0"
[root@mysql03 ~]# vi /etc/sysconfig/keepalived 
KEEPALIVED_OPTIONS="-D -d -S 0"
6.2 編輯 /etc/rsyslog.conf
[root@mysql03 ~]# vi /etc/rsyslog.conf (# 配置檔案最後面加上下面一行)
local0.* /var/log/keepalived.log
6.3 重啟rsyslog：
[root@mysql03 ~]# service rsyslog restart
說明：按上面配置後，keepalived會把日誌記錄到/var/log/keepalived.log。

說明： 6. 操作在主、備上都操作

7. 測試
7.1 啟動所有的相關服務
7.2 檢視 master nginx 上的vip ，檢視漂浮的vip要用 ip a l ，直接ifconfig是看不到的。
[root@mysql03 ~]# ip a l 
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:79:f4:02 brd ff:ff:ff:ff:ff:ff
inet 10.219.24.26/8 brd 10.255.255.255 scope global eth0
inet 10.219.24.100/32 scope global eth0 ##### VIP #####
inet6 fe80::20c:29ff:fe79:f402/64 scope link 
valid_lft forever preferred_lft forever
7.3 tcpdump 抓包， 發現只有 master ip 10.219.24.26 多播包 ，這也符合 VRRP 工作機制
[root@mysql03 ~]# tcpdump -n 'host 224.0.0.18'
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
23:07:46.796186 IP 10.219.24.26 > 224.0.0.18: VRRPv2, Advertisement, vrid 55, prio 100, authtype simple, intvl 1s, length 20
23:07:47.796910 IP 10.219.24.26 > 224.0.0.18: VRRPv2, Advertisement, vrid 55, prio 100, authtype simple, intvl 1s, length 20
23:07:48.798713 IP 10.219.24.26 > 224.0.0.18: VRRPv2, Advertisement, vrid 55, prio 100, authtype simple, intvl 1s, length 20

7.4 master nginx 中 keepalived 關閉 ， 發現 vip 漂到了 slave nginx 上 , 前端訪問未中斷 
-- master nginx
[root@mysql03 ~]# service keepalived stop
Stopping keepalived: [ OK ]
[root@mysql03 ~]# ip a l 
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:79:f4:02 brd ff:ff:ff:ff:ff:ff
inet 10.219.24.26/8 brd 10.255.255.255 scope global eth0
inet6 fe80::20c:29ff:fe79:f402/64 scope link 
valid_lft forever preferred_lft forever

-- slave nginx
[root@redis01 ~]# ip a l 
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:52:56:60 brd ff:ff:ff:ff:ff:ff
inet 10.219.24.23/8 brd 10.255.255.255 scope global eth0
inet 10.219.24.100/32 scope global eth0
inet6 fe80::20c:29ff:fe52:5660/64 scope link 
valid_lft forever preferred_lft forever

7.5 再將之前關閉的 keepalived 開啟，發現 vip 未漂回來， 正好符合主備為 非搶佔式。
[root@mysql03 ~]# service keepalived start
Starting keepalived: [ OK ]
[root@mysql03 ~]# ip a l
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:79:f4:02 brd ff:ff:ff:ff:ff:ff
inet 10.219.24.26/8 brd 10.255.255.255 scope global eth0
inet6 fe80::20c:29ff:fe79:f402/64 scope link 
valid_lft forever preferred_lft forever

7.6 將 slave nginx 上的 nginx 關閉， 發現 slave nginx 上的 keepalived 程式也被指令碼 kill 了， 
順利的完成了 vip 漂回 master nginx 上 ，且 前端訪問不受影響。
-- slave nginx
[root@redis01 ~]# /usr/local/nginx/sbin/nginx -s stop
[root@redis01 ~]# ps -ef|grep keepalived
root 4907 2191 0 23:29 pts/0 00:00:00 grep keepalived

-- master nginx
[root@mysql03 ~]# ip a l 
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:79:f4:02 brd ff:ff:ff:ff:ff:ff
inet 10.219.24.26/8 brd 10.255.255.255 scope global eth0
inet 10.219.24.100/32 scope global eth0
inet6 fe80::20c:29ff:fe79:f402/64 scope link 
valid_lft forever preferred_lft forever