Nginx+Keepalived 主備高可用 安裝與配置

環境說明：
操做系統：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集羣實現負載均衡，Keepalived實現集羣高可用，
主nginx故障後虛擬IP自動漂移到備nginx。

1、 Nginx + Keepalived 安裝

1、1 nginx-1.9.7 編譯安裝

下載地址: http://nginx.org/download/nginx-1.9.7.tar.gz

補充: 安裝 nginx以前，須要先安裝一些依賴包：gcc、pcre、zlib
a、nginx gzip模塊須要zlib庫
b、nginx rewrite模塊須要pcre庫
c、nginx ssl模塊須要openssl庫

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

centos 6.7 配置 yum 本地源 連接參考： http://blog.csdn.NET/zhang123456456/article/details/56690945
二、 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： 配置完畢後能夠看到一個配置概要，概要中的5項必須都有了相應的庫支持
Configuration summary
+ using system PCRE library
+ OpenSSL library is not used
##若是想要安裝openssl模塊，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
三、 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
-- 啓動
[root@mysql03 nginx]# ./sbin/nginx #若是不能正常啓動，多是端口占用
[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： http://10.219.24.26/ #ip換成本身的ip
看到如下頁面內容，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

1、2 安裝 keepalived-1.2.24

1、2.1 安裝 LVS

前提：已經提早配置好本地 Yum 源 配置過程可參考> http://blog.csdn.NET/zhang123456456/article/details/56690945
一、 檢查一下系統內核
安裝以前，首先檢查一下系統內核是否支持LVS的IPVS模塊；自Linux 2.6開始，系統內核徹底內置了LVS的各個模塊。
[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
看到如上輸出信息，則代表系統內核默認支持IPVS模塊。

二、安裝依賴包
因爲是源碼包安裝，因此編譯時須要打上以下依賴包。
# yum -y install kernel-headers glibc-headers glibc-devel libgomp gcc libstdc++-devel gcc-c++

三、 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!
四、 作個 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

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

1、2.2 安裝 keepalived-1.2.24

一、官網下載地址：
[root@mysql03 ~]# wget http://www.keepalived.org/software/keepalived-1.2.24.tar.gz
二、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
三、進入安裝目錄：
[root@mysql03 ~]# cd keepalived-1.2.24

四、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 ：指定使用內核源碼中的頭文件，即include目錄，該參數很重要，只有使用LVS時才用此參數。
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

五、複製腳本和文件：

5.1 拷貝執行文件
[root@mysql03 keepalived-1.2.24]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
5.2 將init.d文件拷貝到etc下,加入開機啓動項
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
5.3 將keepalived文件拷貝到etc下，加入網卡配置
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
5.4 建立keepalived文件夾
[root@node6 keepalived-1.2.16]# mkdir /etc/keepalived
5.5 將keepalived配置文件拷貝到etc下
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
5.6 複製啓動腳本
[root@node6 keepalived-1.2.16]# cp /usr/local/keepalived/sbin/keepalived /etc/keepalived/

六、加入開機啓動項
[root@mysql03 keepalived-1.2.24]# chkconfig --add keepalived #添加時必須保證/etc/init.d/keepalived存在
七、 啓動
[root@mysql03 keepalived-1.2.24]# service keepalived start
Starting keepalived: [ OK ]
八、 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 。

2、 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 http://web_app;
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狀態的腳本
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: 若是開了防火牆，則還需進行防火牆設置，若是沒有防火牆設置，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狀態檢查腳本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 ， 否則腳本 check_nginx.sh 中 nc命令用不了。
[root@mysql03 ~]# rpm -q nc
nc-1.84-24.el6.x86_64

4.2 建立腳本目錄
[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端口，若是有兩個端口，只須要設置爲 PORTS="80 81",則下面也應改成"$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
# 若是mark值爲空說明端口都不通。
# 若是mark等於1，說明有端口是通的。
echo $mark
}

ret1=$(check_ports)
# 若是nginx端口不通，會嘗試重啓一次nginx
if [ "$ret1" != 1 ];then
/sbin/service nginx stop
/sbin/service nginx start
sleep 1
ret2=$(check_ports)
# 若是仍是有端口不通，表示nginx服務不正常，則停掉keepalived，使VIP發生切換
[ "$ret2" != 1 ] && /etc/init.d/keepalived stop
fi

5. 給腳本設置可執行權限：
[root@mysql03 ~]# chmod +x /data/script/check_nginx.sh

說明： 4. 5.操做都在主、備上都操做

補充一點：
若是nginx恢復正常後，keepalived不能自動啓動，須要編寫一個腳本完成這項工做：判斷nginx正常後，拉起keepalived。
腳本放到cron裏每分鐘執行。

6. 開啓keepalived的日誌 （keepalived默認的日誌位置爲 /var/log/messages ，最好咱們將它單獨放置）
6.1 編輯 /etc/sysconfig/keepalived 將 KEEPALIVED_OPTIONS="-D" 改成 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 (# 配置文件最後面加上下面一行)
local0.* /var/log/keepalived.log
6.3 重啓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. 操做在主、備上都操做

7. 測試
7.1 啓動全部的相關服務
7.2 查看 master nginx 上的vip ，查看漂浮的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 工做機制
[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 再將以前關閉的 keepalived 開啓，發現 vip 未漂回來， 正好符合主備爲 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 進程也被腳本 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 forever2: 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