Simple Load-Balancing

Question

I have a simple front-end that accepts all incoming requests and serves mostly static content written in PHP. I forward qualified requests from PHP to the backend using curl and serving the responses again to the user.

I have two (the number might increase over time) similar back-ends doing the heavy lifting. I want to add load balancing (random is fine) and health checks.

All these software load balancers seem to be very complex and hard to setup. Is there an easy solution?

I thought about implementing it my self. Should be straight-forward but probably not really battle proof.

Answer 1

You should probably try NGINX - an HTTP and reverse proxy server. Should be easy to install and configure.

Answer 2

A simple front-end cloud load-balancer should be sufficient.

Enable the following apache modules :

a2enmod proxy proxy_http proxy_balancer

Then, open your /etc/apache2/conf.d/proxy-balancerconfigure and configure the modproxybalancer by adding the following lines :

BalancerMember http://10.0.0.1  
BalancerMember http://10.0.0.4

ProxyPass / balancer://mycluster  

Last, configure your proxy to allow access from all hosts.
Open your /etc/apache2/mods-enabled/proxy.conf and replace the following :

Deny from all

To

Allow from all

Restart apache using `/etc/init.d/apache2 restart``

Hope this help you.

Source : How setup a front-end cloud load balancer in apache

EDIT

For a simple health checker, add this at end of each member :

BalancerMember http://10.0.0.4 connectiontimeout=10 retry=600

EDIT2

For an advanced health checker, see apache mod_proxy_hcheck (only available for apache 2.5 and not in the official repository)

Answer 3

nginx is pretty easy to configure for load balancing:

http://nginx.org/en/docs/http/load_balancing.html