Using mod_spdy With Apache2 On CentOS 6.4

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Follow me on Twitter
Last edited 03/20/2013

SPDY (pronounced “SPeeDY”) is a new networking protocol whose goal is to speed up the web. It is Google’s alternative to the HTTP protocol and a candidate for HTTP/2.0. SPDY augments HTTP with several speed-related features such as

stream multiplexing and header compression. To use SPDY, you need a web server and a browser (like Google Chrome and upcoming versions of Firefox) that both support SPDY. mod_spdy is an open-source Apache module that adds support for the SPDY protocol to the Apache HTTPD server. This tutorial explains how to use mod_spdy with Apache2 on CentOS 6.4.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

SPDY runs over HTTPS, so we need an HTTPS-enabled web site to test SPDY. Please note that SPDY will fall back to HTTPS if the user’s browser does not support SPDY or if things go wrong, so installing mod_spdy doesn’t hurt your existing setup.

I’m assuming that you have a working LAMP setup, as described on Installing Apache2 With PHP5 And MySQL Support On CentOS 6.4 (LAMP).

For testing purposes I will simply use the default SSL web site that comes with the Apache package on CentOS (you don’t need to do this if you already have an SSL web site on your server). If you have no SSL web site, you can enable the default SSL web site as follows:

yum install mod_ssl openssl

openssl genrsa -out ca.key 4096

openssl req -new -key ca.key -out ca.csr

openssl x509 -req -days 365 -in ca.csr -signkey ca.key -out ca.crt

cp ca.crt /etc/pki/tls/certs
cp ca.key /etc/pki/tls/private/ca.key
cp ca.csr /etc/pki/tls/private/ca.csr

vi +/SSLCertificateFile /etc/httpd/conf.d/ssl.conf

SSLCertificateFile /etc/pki/tls/certs/ca.crt
SSLCertificateKeyFile /etc/pki/tls/private/ca.key

/etc/init.d/httpd restart

Go to the default SSL web site’s URL (e.g. and test if it works (I’m using the default self-signed certificate here, that’s why I have a certificate warning, but this has no effect on using SPDY):

(JavaScript must be enabled in your browser to view the large image as an image overlay.)

2 Installing mod_spdy

First make sure at is installed:

yum install at

Google provides Fedora/CentOS packages for mod_spdy on Simply download the correct one for your architecture (32- or 64-bit) to your server…


cd /tmp


cd /tmp

… and install it as follows:

rpm -U mod-spdy-*.rpm

Restart Apache afterwards:

/etc/init.d/httpd restart

The good thing is, mod_spdy needs no configuration, it works out of the box!

(In fact, there is a configuration file, /etc/httpd/conf.d/spdy.conf, but the default settings should be ok.

cat /etc/httpd/conf.d/spdy.conf

LoadModule spdy_module /usr/lib64/httpd/modules/
<IfModule spdy_module>
    # Turn on mod_spdy. To completely disable mod_spdy, you can set
    # this to "off".
    SpdyEnabled on

    # In order to support concurrent multiplexing of requests over a
    # single connection, mod_spdy maintains its own thread pool in
    # each Apache child process for processing requests.  The default
    # size of this thread pool is very conservative; you can override
    # it with a larger value (as below) to increase concurrency, at
    # the possible cost of increased memory usage.
    #SpdyMaxThreadsPerProcess 30

    # Memory usage can also be affected by the maximum number of
    # simultaneously open SPDY streams permitted for each client
    # connection.  Ideally, this limit should be set as high as
    # possible, but you can tweak it as necessary to limit memory
    # consumption.
    #SpdyMaxStreamsPerConnection 100

You can learn more about the configuration options on


3 Testing

Now let’s test if SPDY is working. We need a browser with SPDY support. e.g. Google Chrome. Open Chrome and reload your SSL web site (e.g. – it is important that you reload it so that it can use SPDY (the first time you loaded it in chapter 1 it used normal HTTPS). Afterwards, open a new tab and type in the URL


If everything went well, your SSL vhost should now be listed in the table which means SPDY support is working.

(JavaScript must be enabled in your browser to view the large image as an image overlay.)

(Because of SPDY’s fallback mechanism to HTTPS, your SSL vhost will still work in any other browser that does not support SPDY.)

4 Links

Check out the original source here. apckage, apache httpd server, apache module, apache package, header compression, multiplexing, networking protocol, working lamp, wroking lamp

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s