Setup Varnish 4 on CentOS 6 as a Caching Server and Load Balancer

Published March 29, 2015 • Updated May 3, 2017


In a previous post, I detailed how to setup Varnish 2.1.5 on CentOS 6 as a caching server and load balancer. After setting this up, I realized MP4 files were not streaming and large downloads were taking too long to begin.

Varnish 4 is the latest major release of Varnish and has provided fixes to all of these problems.

This post will be very similar to the previous post, but will provide the new VCL syntax that applies to Varnish 4.

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Setup Varnish 2.1.5 on CentOS 6 as a Caching Server and Load Balancer

Published March 28, 2015 • Updated May 3, 2017


Varnish is a highly regarded HTTP caching server. It sits in front of your web server tier and caches content in RAM so subsequent requests are served as quickly as possible.

Varnish can also be a basic load balancer. Combining a caching server and a load balancer works well when one or more of your web servers becomes unavailable. Because Varnish is also acting as the load balancer, no longer will the end user possibly see a “Service unavailable” message while the load balancer is removing the unhealthy web server from the load balanced pool; They will simply see a cached paged instead.

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Create a KVM Based CentOS 6 OpenStack Cloud Image

Published September 24, 2014


For some reason CentOS does not keep their historical CentOS releases available online in OpenStack cloud image format. They only have the very latest CentOS OpenStack cloud image available (if you know this to be incorrect, please let me know). However, the current and historical CentOS repositories are available online, and you can create your own custom OpenStack cloud image from them.

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Hash root's Password in RHEL and CentOS Kickstart Profiles

Published February 3, 2014 • Updated October 23, 2015


root’s password can easily be set in RHEL and CentOS Kickstart Profiles with the following command:

rootpw "password here"

However, anyone using the Kickstart Profile will see the root password in plain text.

It is possible to hash root’s password in the Kickstart Profile with the following command:

rootpw --iscrypted password_hash

But, how do you generate the password hash? Depending on your authconfig configuration, there are several different ways to do this.

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Create a CentOS 6 Vagrant Base Box from Scratch Using VirtualBox

Published November 11, 2013 • Updated May 13, 2017


Vagrant makes it easy to spin-up local virtual machines using VirtualBox or VMware Fusion. There are many Vagrant Boxes available to use immediately after downloading and installing Vagrant. However, I prefer to know exactly how my virtual machine image is created. This post will walk you through creating a CentOS 6.5 Vagrant Base Box from scratch using VirtualBox.

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Create a CentOS 6 Vagrant Base Box from Scratch Using VMware Fusion

Published October 15, 2013


Vagrant makes it super easy to spin-up local virtual machines using VirtualBox or VMware Fusion. There are many Vagrant Boxes available to use immediately after downloading and installing Vagrant. However, I prefer to know exactly how my virtual machine image is created. This post will walk you through creating a CentOS 6.5 Vagrant Base Box from scratch using VMware Fusion 5 or 6.

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