First, the experiment introduction
Using a three CentOS 7 virtual machine to build a simple Nginx reverse proxy load cluster, three virtual machine addresses and functions
192.168.1.76 nginx load balancer
192.168.1.82 web01 server
192.168.1.78 web02 server
Second, install the nginx software (the following operations must be carried out on three virtual machines)
Some Centos 7.6 does not have the wget command installed, so install it yourself:
yum -y install wget
Install nginx software: (three servers must be installed)
$ wget http://dl.Fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
$ rpm -ivh epel-release-latest-7.noarch.rpm
$ yum install nginx (direct yum installation)
Installation is so simple and convenient, after the installation is complete, you can use systemctl to control the startup of nginx.
$ systemctl enable nginx (join boot)
$ systemctl start nginx (turn on nginx)
$ systemctl status nginx (view status)
After the three servers are installed with nginx respectively, the test can run normally and provide web services. If the error is probably the cause of the firewall, please see the last few steps about the firewall.
Modify the configuration file of the nginx of the proxy server to implement load balancing. As the name implies, multiple requests are distributed to different services to achieve a balanced load and reduce the pressure on a single service.
$ vi /etc/nginx/nginx.conf (modify configuration file, global configuration file)
For more information on configuration, see:
* Official English Documentation: http://nginx.org/en/docs/
* Official Russian Documentation: http://nginx.org/ru/docs/
User nginx;
worker_processes auto; (default is automatic, you can set it yourself, generally no more than cpu core)
error_log /var/log/nginx/error.log; (error log path)
pid /run/nginx.pid; (pid file path)
Load dynamic modules. See /usr/share/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;
Events { accept_mutex on; (set network connection serialization to prevent surprises, default is on) multi_accept on; (set whether a process accepts multiple network connections at the same time, the default is off) worker_connections 1024; (the maximum of a process Number of connections)
}
http {
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main; Sendfile on; # tcp_nopush on; (not commented out here) tcp_nodelay on; keepalive_timeout 65; (connection timeout) types_hash_max_size 2048; gzip on; (open compression) include /etc/nginx/mime.types; default_type application/octet-stream; # Load modular configuration files from the /etc/nginx/conf.d directory. # See http://nginx.org/en/docs/ngx_core_module.html#include # for more information. include /etc/nginx/conf.d/*.conf;
Here to set load balancing, load balancing has multiple strategies, nginx comes with polling, weights, ip-hash, response time and so on.
Default is to split the http load, the way to poll.
is to distribute the request according to the weight, the load with high weight is large
ip-hash, according to ip to allocate, keep the same ip on the same server.
Response time, according to the response time of the server nginx, preferentially distributed to the server with fast response.
The centralized strategy can be combined with
upstream tomcat { (tomcat is a custom load balancing rule name)
ip_hash; (ip_hash is the ip-hash method)
??????server 192.168.1.78:80 weight=3 fail_timeout=20s;
??????server 192.168.1.82:80 weight=4 fail_timeout=20s;
can define multiple sets of rules
}
Server { listen 80 default_server; (default listening port 80) listen localhost; (listening server) server_name _; root /usr/share/nginx/html; # Load configuration files for the default server block. include /etc/nginx/default.d/*.conf; Location / { ( / means all requests, can be customized to set different load rules and services for different domain names)
proxy_pass http://tomcat; (reverse proxy, fill in your own load balancing rule name)
proxy_redirect off; (The following settings can be copied directly. If not, it may lead to some problems such as unauthentication.)
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_connect_timeout 90; The following are just some timeout settings, but don't)
proxy_send_timeout 90;
proxy_read_timeout 90;
}
# location ~.(gif|jpg|png)$ { (for example, write in regular expression)
# root /home/root/ Images;
# }
error_page 404 /404.html; location = /40x.html { } error_page 500 502 503 504 /50x.html; location = /50x.html { } }
Settings for a TLS enabled server.
#
server {
listen 443 ssl http2 default_server;
listen [::]:443 ssl http2 default_server;
server_name _;
root /usr/share/nginx/html;
#
ssl_certificate "/etc/pki/nginx/server.crt";
ssl_certificate_key "/etc/pki/nginx/private/server.key";
ssl_session_cache shared:SSL:1m;
ssl_session_timeout 10m;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;
#
# Load configuration files for the default server block.
include /etc/nginx/default.d/*.conf;
#
location / {
}
#
error_page 404 /404.html;
location = /40x.html {
}
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
}
}
}
After the configuration is updated, the reload configuration can take effect without restarting the service.
nginx -s reload
If you can't access it, it may be because the firewall is open and the port is not open:
Start: systemctl start firewalld
off: systemctl stop firewalld
view status: systemctl status firewalld
boot disable: systemctl disable firewalld
boot enable: systemctl enable firewalld
Open a port:
Add
firewall-cmd --zone=public --add-port=80/tcp --permanent (--permanent is permanent, no failure after restarting this parameter)
Reload
firewall-cmd --reload
view
firewall-cmd -- zone = public --query-port = 80 / tcp
delete
firewall-cmd --zone = public --remove- port = 80 / tcp --permanent
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