InfoTales

Apache 2.2 has been out in year 2008, and just recently, 2.2.13 was released, enhancements and bug fixes introduced. Happily, 2.0 users are migrating to 2.2 due to the excellent performance on static pages.

Here, More exciting innovations found in 2.2 and perhaps peek at one or two of the more esoteric ones. These changes will surprise you.

SNI

SNI is the new feature in Apache 2.2.12, and you can now serve multiple SSL hosts off of one IP address. So there is issue with its documentation but it will resolve soon.

Till now the best documentation is available at http://wiki.apache.org/httpd/NameBasedSSLVHostsWithSNI.

Graceful Stop

There is an issue with old apache server, when stopped it will kill the all existing connection, but now there is an option for graceful restart. It is used to change the server setting without restarting the server. I will serve the current users, and new connections will come with new config

$  httpd -k graceful-restart

But the new option introduced graceful-stop this option will stop the apache server and complete current request in process. So it will stop the server when the request is complete.

$ httpd -k graceful-stop

This can reduce angry customers while settings are being changed on server

mod_substitute

Apache 2.2 introduced mod_substitute, which includes some of the functionality of both of the latter modules and allows you to modify the response that is being sent to the web client, using regular expressions. To use mod_substitute, you must know enough about regular expressions to express your desired change. For example, if you are proxying a back-end server images.local and want to replace that hostname in URLs with its external hostname, you would do the following:

AddOutputFilterByType SUBSTITUTE text/html

Substitute s/images.local/images.mysite.com/i

In this case, the i on the end indicates that the substitution should happen in a case-insensitive fashion. The AddOutputFilterByType directive specifies what kind of files the substitution should affect. You don’t want to do substitutions on images or PDF files, for example, as it will corrupt them and result in garbage.

It can also used in the .htaccess

mod_proxy_balancer

This is the new excellent feature. Before this, we had to use the hardware or software load balancer. Now apache 2.2 had introduced the functionality built in.

Its really a full-featured load balancing proxy for free, and included in your Apache 2.2 server.

To get started with mod_proxy_balancer, you can define your cluster pool like this:

<Proxy balancer://mycluster>
BalancerMember http://192.168.1.50:80
BalancerMember http://192.168.1.51:80
BalancerMember http://192.168.1.51:80
</Proxy>

Then, tell your server to proxy requests through to those servers:

ProxyPass /test balancer://mycluster/

This is the reference article to study about it more http://httpd.apache.org/docs/2.2/mod/mod_proxy_balancer.html