Cluster architecture - Nginx load balancing and Tomcat cluster

1: Load balancing technology

1. Introduction of load balancing technology

Load balancing technology is a concept that evenly distributes the use of resources.

Load balancing: distribute traffic and requests to different servers. Distribute the flow evenly (ideal state)

effect:

Server disaster recovery traffic distribution

Main functions:

① The traffic distribution request reduces the single case pressure on average

Other functions:

② Hide the real back-end services securely

③ Shield illegal requests (layer 7 load balancing)

2. Load balancing classification

1) Layer 2 load balancing (mac)

According to the OSI model, the load is divided into two layers. Generally, the virtual MAC address is used. The external requests for the virtual MAC address are received by load balancing, and then the actual MAC address response of the back-end is allocated

**2) Three layer load balancing (ip)**

Generally, the virtual IP address mode is adopted. After the external requests for virtual IP addresses are received by load balancing, the actual IP address response of the back end is allocated

3) Four layer load balancing (tcp) is the load balancing of network transportation

On the basis of three-tier load balancing, the request is received with ip+port and then forwarded to the corresponding machine

4) Seven layer load balancing (http) intelligent load balancing

According to the virtual url or IP, the host receives the request and then turns to the corresponding processing server (reverse proxy)

3. Common implementation methods

Implementation classification:

① Software level, high cost performance and strong controllability

② The hardware level has good performance and the price ranges from tens of thousands to hundreds of thousands

Hardware implementation mode:

F5 BIG-IP layer 4 and layer 7

Software implementation mode:

OSI layering	Implementation mode
Seventh floor	Nginx,HAProxy
four layers	LVS, HAProxy, Nginx (after version 1.9)

Comparison between the fourth floor and the seventh floor:

II Experimental analysis of Nginx load balancing

Usually, a tomcat site can not be used in the production environment alone because it may have a single point of failure and can not cope with too many complex and diverse requests from customers. Therefore, we need a more reliable solution to improve the web site architecture
Nginx is an http server software with superior performance. It can support the response of up to 50000 concurrent connections, has strong static resource processing ability, runs stably, and consumes very low system resources such as memory and CPU. At present, many large websites use nginx server as the reverse proxy and load balancer of back-end website programs to improve the load concurrency of the whole site

III Network topology and experimental environment

type	IP address	system	software package
Nginx server	192.168.100.140	centos7	nginx-1.12.2.tar.gz
Tomcat server 1	192.168.100.150	centos7	apache-tomcat-8.5.16.tar.gz;jdk-8u91-linux-x64.tar.gz
Tomcat server 2	192.168.100.160	centos7	apache-tomcat-8.5.16.tar.gz;jdk-8u91-linux-x64.tar.gz
Client	192.168.100.10	Windows10

IV Specific operation steps and verification

Tomcat01 configuration

1.decompression jdk Compressed package
systemctl stop firewalld
setenforce 0 
tar zxvf jdk-8u91-linux-x64.tar.gz -C /usr/local/

2.to configure Java environment variable
vim /etc/profile
'add to'
export JAVA_HOME=/usr/local/jdk1.8.0_91
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

3.load JAVA environment variable
source /etc/profile

4.decompression Tomcat software package
tar zxvf apache-tomcat-8.5.16.tar.gz -C /usr/local

5.Modify the directory name for easy operation
cd /usr/local
mv apache-tomcat-8.5.16/ tomcat
6.Create soft links to optimize service control
ln -s /usr/local/tomcat/bin/startup.sh /usr/local/bin/
ln -s /usr/local/tomcat/bin/shutdown.sh /usr/local/bin/

7.establish web Site, edit site content,Add test page
mkdir -pv /web/webapp1
vim /web/webapp1/index.jsp
 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
 <head>
  <title>JSP test1 page</title>
 </head>
 <body>
  <% out.println("Welcome Tomcat 01");%>
 </body>
</html>

8.modify Tomcat of server.xml File, define a virtual host, and point the website file path to the established/web/webapp1，stay hos Segment increase context paragraph
[root@tomcat01 ~]# vim /usr/local/tomcat/conf/server.xml
//Line 148
      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">
        <Context docBase="/web/webapp1" path="" reloadable="false">
        </Context>
 //Note: docbase: document reference directory of web application
reloadable Set whether the monitoring "class" changes
path=""Set default class

9.Turn off the security function and turn on the service
startup.sh 
systemctl stop firewalld
setenforce 0

Tomcat02 configuration is basically the same as that of 01, index The output Welcome Tomcat 02 defined on the JSP homepage is different here for differentiation

1.decompression jdk Compressed package
tar xzvf jdk-8u231-linux-x64.tar.gz -C /usr/local

2.to configure JAVA environment variable
vim /etc/profile  //Append to end
export JAVA_HOME=/usr/local/jdk1.8.0_231
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

3.load JAVA environment variable
source /etc/profile

4.decompression tomcat software package
tar xzvf apache-tomcat-8.5.50.tar.gz -C /usr/local

5.The directory name is easy to modify and operate
cd /usr/local
mv apache-tomcat-8.5.50/ tomcat/

6.Create soft links to optimize service control
ln -s /usr/local/tomcat/bin/startup.sh /usr/local/bin/
ln -s /usr/local/tomcat/bin/shutdown.sh /usr/local/bin/

7.establish web Site, edit site content
mkdir -pv /web/webapp1
vim /web/webapp1/index.jsp
 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
 <head>
  <title>JSP test1 page</title>
 </head>
 <body>
  <% out.println("Welcome Tomcat 02");%>
 </body>
</html>
~

8.modify Tomcat of server.xml File, define a virtual host, and point the website file path to the established/web/webapp1，stay hos Segment increase context paragraph
[root@tomcat02 ~]# vim /usr/local/tomcat/conf/server.xml
      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">
        <Context docBase="/web/webapp1" path="" reloadable="false">
        </Context>
 
9.Turn off the security function and turn on the service
shutdown.sh
startup.sh 
systemctl stop firewalld
setenforce 0

Configuration of Nginx server

1.Unzip package
tar xzvf nginx-1.12.2.tar.gz -C /opt

2.Download relevant software packages
yum install pcre-devel zlib-devel gcc gcc-c++ make -y

3.establish nginx User
useradd -M -s /sbin/nologin nginx

4.Compile and install nginx
cd /opt/nginx-1.12.2/
./configure \
--prefix=/usr/local/nginx \
--user=nginx --group=nginx \
--with-http_stub_status_module \    //Enable status statistics
--with-http_gzip_static_module \    //Enable gzip static compression
--with-http_flv_module     //Enable the flv module to provide time-based offset files for seeking memory usage
 
make && make install
 
5.edit nginx Master profile for
vim /usr/local/nginx/conf/nginx.conf
 #keepalive_timeout  0;
    keepalive_timeout  65;
    #gzip  on;
    upstream tomcat_server {              //Add the upstream function and configure the tomcat server pool name customization, but ensure that it is consistent with the following call name
        server 192.168.100.150:8080 weight=1;   //Weight stands for weight
        server 192.168.100.160:8080 weight=2;
        }
 
    server {
        listen       80;
        server_name  localhost;
        #charset koi8-r;
        #access_log  logs/host.access.log  main;
 
        location / {
            root   html;
            index  index.html index.htm;
            proxy_pass http://tomcat_server;    // Add the reverse proxy to the set Tomcat server pool. The name of the call here should be consistent with the function name above
        }

		
6.Optimize service control mode
ln -s /usr/local/nginx/sbin/nginx /usr/local/sbin
 
7.Check the syntax for correct configuration
[root@nginx ~]# nginx -t
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@nginx ~]# 
 
8.Turn off the security function and turn it on nginx service
systemctl stop firewalld
setenforce 0
nginx  				//Enable nginx service
netstat -ntap | grep nginx
killall -1 nginx 	//Restart nginx service

9. Page Test
 Access proxy server 192.168.100.140   Refresh multiple times and view weighted polling