load balancer

 

test servers:

echp 'PHP Server 1'> s1

echp 'PHP Server 2'> s2

echp 'PHP Server 3'> s3

php -S localhost:10001 s1

php -S localhost:10002 s2

php -S localhost:10003 s3

curl http://localhost:10001

curl http://localhost:10002

curl http://localhost:10003

load-balancer.conf

----

events{}

http{

server{

listen 8888;

location / {

proxy_pass 'http://localhost:10001/';

}

}

}

------

nginx -c /<path>/load-balancer.conf

curl http://localhost:8888

while sleep 0.5;do curl http://localhost:8888; done

-------

load-balancer.conf

----

events{}

http{

upstream php_servers{

 server localhost:10001;

 server localhost:10002;

 server localhost:10003;

}

server{

listen 8888;

location / {

proxy_pass http://php_servers;

}

}

}

---

default behavior is round robin---to send next request to next server in upstream

sticky sessions ---request is bound to users ip hash and routes to same server for the session

load-balancer.conf

----

events{}

http{

upstream php_servers{

 ip_hash;

 server localhost:10001;

 server localhost:10002;

 server localhost:10003;

}

server{

listen 8888;

location / {

proxy_pass http://php_servers;

}

}

}

distribute requests based on load and pass them to server with least number of active connections

upstream php_servers{

least_conn;   //ip_hash;

---

---

}