mirror of
https://github.com/bpetschowitsch/weba.git
synced 2026-07-21 17:02:12 +00:00
bpetschowitsch
2.8 KiB
2.8 KiB
Load Balancer
Simple guide to setup a load balancer based on nginx.
Backend Server
First we need to create two backend-server:
cd /etc/nginx/sites-available
sudo vi backend_server
server {
listen 127.0.0.1:8080;
server_name _;
root /var/www/backend/srv1;
index index.html;
location / {
try_files $uri $uri/ =404;
}
}
server {
listen 127.0.0.1:8081;
server_name _;
root /var/www/backend/srv2;
index index.html;
location / {
try_files $uri $uri/ =404;
}
}
enable the new servers and validate configuration:
sudo ln -s /etc/nginx/sites-available/backend_server backend_server
sudo nginx -t
restart nginx
sudo systemctl reload nginx
to verify the two servers are running:
sudo netstat -anp | grep -E "8080|8081"
simple html
the new webserver need an index.html
cd /var/www/
sudo mkdir -p backend/srv1
sudo mkdir -p backend/srv2
srv1
index.html of server one:
sudo vi backend/srv1/index.html
<html>
<head>
<title>Welcome!</title>
</head>
<body>
<h1>Hello World! I am backend-server 1!</h1>
</body>
</html>
srv2
index.html of server two:
sudo vi backend/srv2/index.html
<html>
<head>
<title>Welcome!</title>
</head>
<body>
<h1>Hello World! I am backend-server 2!</h1>
</body>
</html>
Load Balancer
lets create a new server as load balancer.
cd /etc/nginx/sites-available
sudo vi loadbalancer
upstream my_backend_server {
# default round-robin; other options: least_conn; ip_hash;
# or using custom hash based on e.g. cookies: hash $cookie_<cookie-name> consistent;
server 127.0.0.1:8080;
server 127.0.0.1:8081;
}
server {
listen 80;
server_name *mydomain*;
location / {
proxy_pass http://my_backend_server;
}
}
enable the new configuration & verify:
sudo ln -f -s /etc/nginx/sites-available/loadbalancer *mydomain*
sudo nginx -t
restart nginx:
sudo systemctl reload nginx
Test
load the website and refresh it serveral times...
simulate server crash
simply change the listen port of one the backend-server (e.g. srv2 listen on 8082). Restart nginx. Retry the test.
simulate server failure
before location add directive: return 500;. Restart nginx. Retry the test.
Handle server failure
edit load balancer configuration:
[...]
location / {
proxy_pass http://my_backend_server;
proxy_next_upstream timeout http_500;
}
[...]
validate configuration, restart nginx and repeat the server failure test.