Ten of three Linux phases: nginx reverse proxy load balancing

Keywords: Linux Nginx curl Database Web Server

10. nginx reverse proxy load balancing

(1) Description of LNMP architecture migration database

Migrating databases: Using the database backup command (mysql mysqladmin mysqldump)

1) Back up database information

 mysqldump -uroot -poldboy123 --all-databases >/tmp/bak.sql
 ll /tmp/bak.sql -h
 scp /tmp/bak.sql 172.16.1.51:/tmp/

2) Restore database communications

 ##db01 
 mysql -uroot -poldboy123 </tmp/bak.sql
 ###db01 Add New User
 grant all on wordpress.* to wordpress@'172.16.1.0/255.255.255.0' identified by 'oldboy123';
 flush privileges;
 mysql -uwordpress -poldboy123 -h 172.16.1.51

3) After the database migration, modify the configuration file of the website connection database

Mysql-uwordpress-poldboy123-h 172.16.1.51 <--Test site web server connectivity to migrated database before modifying configuration file	
VIM wp-config.php <--Modify database connection parameter information on wordpress
 /** MySQL host*/
Define ('DB_HOST','172.16.1.51') <--Modify the host information for the connection to 172.16.1.51
 Note: The web server database can now be closed

4) Stop MySQL service on nginx server

/etc/init.d/mysql stop

(2) Instructions for migrating LNMP schema data to NFS storage

01: Move the data out of the original directory first

 cd /application/nginx/html/blog/wp-content/uploads
 mkdir /tmp/wordpress_backup -p
 mv ./* /tmp/wordpress_backup/
 
 Where to store the data locally and how to get it
 Get the address information of the resource by right clicking on the page of the website
 (2) find command using -mmin 5 
 3. Use inotify service to monitor directory data changes

02:Configure Create Shared Directory on NFS Server

 vim /etc/exports
 /data 172.16.1.0/24(rw,sync,all_squash)
 showmount -e 172.16.1.31
 mount -t nfs 172.16.1.31:/data /mnt/
 
 showmount -e 172.16.1.31
 mount -t nfs 172.16.1.31:/data/ ./uploads/
 mv /tmp/wordpress_backup/* ./

(3) nginx reverse proxy load balancing function

Client====Proxy Server===web Server	
Client sees server==proxy server	
Proxy server===web server
 Reverse Proxy Functional Architecture
 3 web servers to form a web server cluster
web01  10.0.0.7   172.16.1.7
web02  10.0.0.8   172.16.1.8
web03  10.0.0.9   172.16.1.9
 1 Load Balancing Server
lb01   10.0.0.5   172.16.1.5

1. Deploy web server

First mileage: install and deploy nginx software

mkdir /server/tools -p
cd /server/tools
wget http://nginx.org/download/nginx-1.12.2.tar.gz
tar xf nginx-1.12.2.tar.gz
yum install -y pcre-devel openssl-devel
useradd -M -s /sbin/nologin www
cd nginx-1.12.2
./configure --prefix=/application/nginx-1.12.2 --user=www --group=www --with-http_ssl_module --with-http_stub_status_module
make && make install
ln -s /application/nginx-1.12.2 /application/nginx
/application/nginx/sbin/nginx
netstat -lntup|grep nginx

Second mileage: Edit nginx configuration file

server {
    listen       80;
    server_name  www.etiantian.org;
    root   html/www;
    index  index.html index.htm;
}
server {
    listen       80;
    server_name  bbs.etiantian.org;
    root   html/bbs;
    index  index.html index.htm;
}
scp -rp /application/nginx/conf/nginx.conf 172.16.1.8:/application/nginx/conf/
scp -rp /application/nginx/conf/nginx.conf 172.16.1.9:/application/nginx/conf/

Mileage 3: Creating a simulated test environment

mkdir /application/nginx/html/{www,bbs} -p
for name in www bbs;do echo "$(hostname) $name.etiantian.org" >/application/nginx/html/$name/oldboy.html;done
for name in www bbs;do cat /application/nginx/html/$name/oldboy.html;done

Fourth mileage: Test access on a load balancing server

 curl -H host:www.etiantian.org 10.0.0.7/oldboy.html
 web01 www.etiantian.org
 curl -H host:bbs.etiantian.org 10.0.0.7/oldboy.html
 web01 bbs.etiantian.org
 curl -H host:www.etiantian.org 10.0.0.8/oldboy.html
 web02 www.etiantian.org
 curl -H host:bbs.etiantian.org 10.0.0.8/oldboy.html
 web02 bbs.etiantian.org
 curl -H host:www.etiantian.org 10.0.0.9/oldboy.html
 web03 www.etiantian.org
 curl -H host:bbs.etiantian.org 10.0.0.9/oldboy.html
 web03 bbs.etiantian.org

Deploying a load balancing server

First mileage: install and deploy nginx software

mkdir /server/tools -p
cd /server/tools
wget http://nginx.org/download/nginx-1.12.2.tar.gz
tar xf nginx-1.12.2.tar.gz
yum install -y pcre-devel openssl-devel
useradd -M -s /sbin/nologin www
cd nginx-1.12.2
./configure --prefix=/application/nginx-1.12.2 --user=www --group=www --with-http_ssl_module --with-http_stub_status_module
make && make install
ln -s /application/nginx-1.12.2 /application/nginx
/application/nginx/sbin/nginx
netstat -lntup|grep nginx

Second milestone: Write nginx reverse proxy profile

grep -Ev "#|^$" nginx.conf.default >nginx.conf

//Official link: http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream
Syntax:	upstream name { ... }
Default:	—
Context:	http
eg: 
upstream oldboy {
   server 10.0.0.7:80;
   server 10.0.0.8:80;
   server 10.0.0.9:80;
}
//Description: The upstream module is similar to specifying an address pool or a web server group

//Official link: http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_pass
Syntax:	proxy_pass URL;
 Default:	—
 Context:	location, if in location, limit_except
eg: 
location / {
   proxy_pass http://oldboy;
}
 //Description: proxy_pass is mainly used to throw user access requests to the corresponding node servers in the upstream module

worker_processes  1;
 events {
     worker_connections  1024;
 }
 http {
     include       mime.types;
     default_type  application/octet-stream;
     sendfile        on;
     keepalive_timeout  65;
     upstream oldboy {
         server 10.0.0.7:80;
         server 10.0.0.8:80;
         server 10.0.0.9:80;
     }
     server {
         listen       80;
         server_name  localhost;
         root   html;
         index  index.html index.htm;
       location / {
         proxy_pass http://oldboy;
        }   
     }
 }

/application/nginx/sbin/nginx -t
/application/nginx/sbin/nginx -s reload

Third mileage: conducting access load balancing server tests

1)Testing with a browser
   //Resolve hosts
   http://Www.etiantian.org/oldboy.html <--Use ctrl+F5 to refresh tests to check for load scheduling
 2)utilize curl Command to test
    [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
    web01 www.etiantian.org
    [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
    web02 www.etiantian.org
    [root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.5/oldboy.html
    web03 www.etiantian.org

(4) Detailed function description of Nginx reverse proxy load balancing module

ngx_http_upstream_module
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream

(1) Description of module common functions:

1) Define backend cluster web node information, define an address pool

upstream oldboy {
server 10.0.0.7:80;
server 10.0.0.8:80;
server 10.0.0.9:80;
}

2) Implement weight value load access function

upstream oldboy {
server 10.0.0.7:80 weight=3;
server 10.0.0.8:80 weight=1;
server 10.0.0.9:80 weight=1;
}

3) Define the number of backend access failures-max_fails

upstream oldboy {
server 10.0.0.7:80 weight=3 max_fails=3;
server 10.0.0.8:80 weight=1 max_fails=3;
server 10.0.0.9:80 weight=1 max_fails=3;
}

4) Define the interval between back-end failed retries-fail_timeout

upstream oldboy {
server 10.0.0.7:80 weight=3 max_fails=3 fail_timeout=10s;
server 10.0.0.8:80 weight=1 max_fails=3;
server 10.0.0.9:80 weight=1 max_fails=3;
}
	Description: After several failed attempts, the corresponding node will be given another chance after the time-out period has elapsed

5) Define a hot standby node for back-end services-backup

upstream oldboy {
server 10.0.0.7:80;
server 10.0.0.8:80;
server 10.0.0.9:80 backup;
}

(2) Module common scheduling algorithms:

1)Define Polling Scheduling Algorithm-rr-Default Scheduling Algorithm
//Take an equal distribution

2)Define Weight Scheduling Algorithm-wrr
//An able man is always busy

3)Define a static scheduling algorithm-ip_hash
upstream oldboy {
ip_hash;
server 10.0.0.7:80;
server 10.0.0.8:80;
server 10.0.0.9:80 backup;
}
//Note: When configuring ip_hash, backup and weight parameters must not appear together

4)Define the minimum number of connections-least_conn
upstream oldboy {
least_conn;
server 10.0.0.7:80;
server 10.0.0.8:80;
server 10.0.0.9:80 backup;
}

(3) Module Common Functions (ngx_http_proxy_module)

proxy_set_header 	--- Set up a reverse proxy server to web Server's HTTP Request header information in a message
server {
listen       80;
server_name  www.etiantian.org;
root   html;
index  index.html index.htm;
location / {
proxy_pass http://oldboy;
proxy_set_header host $host;
}
}
server {
listen       80;
server_name  bbs.etiantian.org;
proxy_set_header host $host;
root   html;
index  index.html index.htm;
location / {
proxy_pass http://oldboy;
proxy_set_header host $host;
}
}
//Note: With the above configuration, access load balancing can be achieved to see different virtual host page information (oldboy, equivalent to using ip address to access the virtual host, the first server is accessed by default)

server {
listen       80;
server_name  www.etiantian.org;
root   html;
index  index.html index.htm;
location / {
proxy_pass http://oldboy;
proxy_set_header host $host;
proxy_set_header X-Forwarded-For $remote_addr;
} 
}
server {
listen       80;
server_name  bbs.etiantian.org;
root   html;
index  index.html index.htm;
location / {
proxy_pass http://oldboy;
proxy_set_header X-Forwarded-For $remote_addr;
} 
}
//Description: Implement user access to reverse proxy service to record real user IP address information in web server logs

(5) Cases:

Conduct business case needs combing first:
Implement upload upload server pool to process requests when users request a www.etiantian.org/upload/xx address.
Implements a static server pool to process requests when a user requests a www.etiantian.org/static/xx address.
In addition, for other access requests, all requests are processed by the default dynamic server pool.
    User Request (URI) Processing Request Server Site Directory Function
    /upload. 10.0.0.8:80. html/www/upload. upload server
    /static. 10.0.0.7:80. html/www/static. static static static server
    / 10.0.0.9:80 html/www default

Solutions:

1) Complete nginx site server configuration

First mileage: Creating a test environment

# Create upload directory on 10.0.0.8 host and generate site test page file
cd /application/nginx/html/www/
mkdir upload
cp oldboy.html upload/

# Create a static directory on the 10.0.0.7 host and generate a Web site test page file
cd /application/nginx/html/www/
mkdir static
cp oldboy.html static/	

# Create default test page file on 10.0.0.9 host

Second mileage: access testing using lb01

# Test for 10.0.0.8 access
curl -H host:www.etiantian.org 10.0.0.8/upload/oldboy.html
web02 www.etiantian.org

# Test for 10.0.0.7 access
curl -H host:www.etiantian.org 10.0.0.7/static/oldboy.html
web01 www.etiantian.org

# Test for 10.0.0.9 access
curl -H host:www.etiantian.org 10.0.0.9/oldboy.html
web03 www.etiantian.org

2) Complete nginx reverse proxy server configuration

First mileage: configure upstream module information

upstream upload {
server 10.0.0.8:80;
}
upstream static {
server 10.0.0.7:80;
}
upstream default {
server 10.0.0.9:80;
}

Second mileage: Configure proxy_pass module information

server {
listen       80;
server_name  www.etiantian.org;
root   html; 
index  index.html index.htm;
location / {
proxy_pass http://default;
proxy_set_header host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
location /upload {
proxy_pass http://upload;
proxy_set_header host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
location /static {
proxy_pass http://static;
proxy_set_header host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}

Example 2:

Display different page information based on user request for client software

Solution:
1) nginx site server configuration
First mileage: Creating a test environment

# Create upload directory on 10.0.0.8 host and generate site test page file
cd /application/nginx/html/www/
cat oldboy.html

# Create a static directory on the 10.0.0.7 host and generate a Web site test page file
cd /application/nginx/html/www/
cat oldboy.html 

# Create default test page file on 10.0.0.9 host
cd /application/nginx/html/www/
cat oldboy.html 

//Test access:
[root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.7/oldboy.html
web01 www.etiantian.org
[root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.8/oldboy.html
web02 www.etiantian.org
[root@lb01 conf]# curl -H host:www.etiantian.org 10.0.0.9/oldboy.html
web03 www.etiantian.org

2) nginx reverse proxy server configuration