In the first article in this series I pointed out some problems I and other LibreOffice users have with the standard LibreOffice color palette, and I talked about how colors are specified, both on computers in general and within LibreOffice .soc files. Let's now see how to generate a new set of colors.

Recently, I was working on an Impress presentation, and I needed more colors than LibreOffice provides with its standard color picker. Specifically, I needed several light colors, but the standard color list includes only a few light blue possibilities. I could have defined my own colors manually using the Color Picker, but "mixing" colors by specifying RGB or CMYK numbers is a cumbersome, hit-or-miss process. LibreOffice also lets users load predefined color libraries, but none of the ones I found suited me. Instead, by working with web-standard colors plus a little bit of awk scripting, I managed to create my own color list, providing well-organized colors, grouped in families, with as many color variations as I wanted.

One of the strengths of Puppet, the IT automation application, is the flexibility it offers administrators to manage multiple servers through the use of customized templates and remote system facts, which are essentially variable values from remotely managed nodes. Thanks to this flexibility you can administer each Puppet node with instructions tailored for its specific environment – something you cannot do with simpler multiserver administration tools.

If an attacker knows that your server is listening on a given port, potentially ready to allow entrance, he can target it for a security breach. An open port can be seen as a door to your system, and a password would be its key. But what would happen if the door were hidden, invisible, and you needed to use something special to make it visible again? A technique called port knocking keeps ports closed until users provide a secret knock sequence that only then allows them access to your site.

phpMyAdmin is popular with both individuals and enterprise users who want a graphical interface for administering MySQL databases. Although the app has an expansive list of features, most people don't use it for much beyond basic tasks such as creating new databases. Here are some features tucked beneath phpMyAdmin's folds that can make you more efficient.

The GIMP is a wonderful image editor, but it might be overkill if all you want to do is annotate an image. If you want to highlight a part of an image, so that for example the audience for your presentation can focus on a particular aspect, you'll probably find it easier and more intuitive to do that in a program such as Dia or OpenOffice Draw. Let's see how to annotate an image in all three programs.

It's easy to get started with the search server Apache Solr and the popular CMS platform Drupal, as described in our previous tutorial on setting up Solr 4.2 with Drupal 7. Straight out of the box Solr handles basic text searching, but you can increase its power by adding faceted search – the ability to filter on specific facets or aspects of the data on a site. For example, on a Drupal site you might want to be able to filter your searching by author, date, or tags. Solr's faceted search allows users to combine this type of filtering with text searching to find the information they're after faster. Read on for the lowdown on setting up and configuring basic faceted search using Solr 4.2 and Drupal 7, running on Apache on Linux.

Last month's release of FreeNAS 8.3.1 adds new functionality that allows system administrators of the open source-based network attached storage solution to encrypt entire disks while using ZFS. ZFS has been the primary filesystem for FreeNAS since FreeNAS 8, and has supplanted FreeBSD's UFS as the project's focus. The new security functionality applies only to ZFS and is the first time that FreeNAS has supported encryption.

If you're looking for Linux-based, hardware-agnostic storage software, check out Gluster, an open source project for creating a distributed filesystem. It provides fast performance, high availability, and horizontal scalability by spreading storage volumes over redundant cluster nodes. Here's how you can build a Gluster distributed storage system yourself.

Solr is an open source search server based on Apache Lucene. Lucene provides Java-based indexing and a search library, and Solr extends it to provide a variety of APIs and search functionality, including faceted search and hit highlighting, and handles Word and PDF document searching. It also provides caching and replication, making it scalable, robust, and very fast.