Category: Uncategorized

Content Updates With W3 Total Cache & RackSpace Cloud Files

August 31, 2015

We get frequent questions from WordPress clients with W3 Total Cache (W3TC) and RackSpace Cloud Files (RCF) content distribution network (CDN) about how to make changes to the website visible. First some general notes: Content changes or updates to pages or posts do not involve the CDN so no special actions are required. W3TC will automatically flush old pages and post revisions from it’s caches. Media files uploaded through WordPress admin will be automatically uploaded to the CDN and can be immediately used in post or pages with no additional action. Files that are changed via FTP will required additional action. This included media files, CSS and Javascript as discussed below. As an example, let’s assume that you’ve modified you themes primary stylesheet at: wp-content/themes/mytheme/style.css You made the modification by downloading the file, editing on your workstation and then uploading via SFTP back to the server. In this case W3TC

GlusterFS Cluster with CentOS on RackSpace Cloud

November 28, 2013

We want to build a high-availability storage cluster based on GlusterFS using RackSpace Cloud Servers on CentOS. Also we want to use RackSpace Cloud Networks to provide private networks for replication and cluster access. Finally we want to use RackSpace Cloud Block Storage with LVM and XFS to simplify future expansion. This article is based on a previous article we published on the same topic for Ubuntu: GlusterFS Cluster With Ubuntu On RackSpace Cloud As shown in the diagram, we’ll have two Cloud Networks, one for replication between the servers and one for access by clients to the storage. The next diagrams shows the filesystem layers – local, CBS, LVM, XFS and finally GlusterFS. Part 1 – Server Setup 1. Create servers and networks – Login to your RackSpace Cloud account and create two server following these guidelines: Make sure you choose a Next Gen region for the servers. For

Percona XtraDB Cluster On CentOS

November 14, 2013

This article is built off of a similar article we published last month: Percona XtraDB Cluster on Ubuntu The primary difference is this time we’re going to use CentOS instead of Ubuntu. In this article we’re going to build a Percona XtraDB Cluster using a pair of RackSpace Cloud Servers. Percona XtraDB Cluster is a MySQL compatible replacement supporting multi-master replication. For this project we’ll use the latest CentOS release and we’re going to use RackSpace Cloud Networks to setup an isolated segment for the replication between the cluster nodes. We’ll do two nodes in the cluster but you can add additional nodes as desired. Finally we’ll use a RackSpace Cloud Load Balancer to distribute traffic between the nodes. To get started, create the cloud servers from the RackSpace control panel using the following guidelines: Make sure you choose a Next Gen region for the servers. For the Image choose

Install Scalr Command Line Utilities on CentOS 6.4

August 10, 2013

For managing cloud clusters we love Scalr both as a hosted service and using the open-source self-hosted version. One of the best features is the easy to install and use command line utilities. Here are the docs: http://wiki.scalr.com/display/docs/Scalr+Command+Line+Tools Here’s the install steps for CentOS 6.4: 1. Install python setuptools package:

yum install python-setuptools

1	yum install python-setuptools

2. Install python scalr package:

easy_install scalr

1	easy_install scalr

3. Run scalr configure to setup access credentials. See the docs for details but something like this:

scalr configure -i d41d8cd98f00b204 \
     -a 3bEGXWzaoT92BMhOaqv13bEGXWzaoT92BMhOaqv13bEGXWzaoT92BMhOaqv1+0=

1 2	scalr configure -i d41d8cd98f00b204 \ -a 3bEGXWzaoT92BMhOaqv13bEGXWzaoT92BMhOaqv13bEGXWzaoT92BMhOaqv1+0=

And now your ready to go.

Find Malware Hidden In Image Files

March 21, 2013

Hackers will often try to hide malicious code in files with image extensions like “.gif”. Here’s a command line that will help identify suspicious files:


find -name '*.gif' -o -name '*.jpg' -o -name '*.png' -exec file {} \; \
   | grep -v 'GIF image data' \
   | grep -v 'PNG image data' \
   | grep -v 'JPEG image data' \
   | grep -v _vti_cnf

find -name '*.gif' -o -name '*.jpg' -o -name '*.png' -exec file {} \; \

| grep -v 'GIF image data' \

| grep -v 'PNG image data' \

| grep -v 'JPEG image data' \

| grep -v _vti_cnf

Not every file returned in this scan is malware. Pay special attention to files of type text. It’s not unusual to see an image file where the file extension does not match the content – so a .png file might actually contain a JPEG file.