First a little background. Failover is defined as, "activating redundant servers to replace servers that have become unavailable." The grouping is typically one primary server and one secondary server. This process can be configured to happen automatically, and it most typically is used for Web servers, mail servers, database servers, firewalls, file servers, DNS servers, or any server for which high availability is a priority.

In order for a secondary server to take over for a primary server that has become disabled, it needs to be aware of the primary server's condition. A message is continuously sent between the servers to notify each other of their existence, usually via a special hardware cable. A signal goes over the cable continuously, at regular rapid intervals. If messages are not received from the primary server, it is considered to have gone off line, and all resources that it owned are failed over to the secondary server.

Heartbeat is a free open source product widely used to configure failover redundancy. The project got its start in 1998, and has been in production status since 2000. The lead developer, Alan Robertson, is a full time employee of IBM. Intel is also a sponsor, contributing developers on their payroll. Heartbeat is included free with every distribution except Red Hat, and Red Hat users can simply download it. A major goal of the Heartbeat project is to provide flexibility, so users are able to configure the software in a variety of ways. Security is also important, so all packets are digitally signed.

Heartbeat Features

• Free open source failover software
• Allows server redundancy at very low cost
• Flexible -- variety of configurations possible
• Can also achieve data replication with DRBD project in conjunction with Heartbeat
• Secure -- packets are digitally signed
• Webmin module available

The project is planning to expand to support larger clusters, and will add additional monitoring features. In the future, they would also like to monitor hardware temperature to detect imminent failure. The project is currently adding full time developers to achieve these goals.

Commercial support is provided by Tummy.com. Most Linux consulting groups also deploy and support redundancy with Heartbeat. The project mailing lists are known for being especially helpful to those new to the product.

The DRBD (Distributed Replicated Block Device) project allows for a software RAID on Linux at a very low cost. DRBD is an open source project dedicated to data replication, and is frequently being used in conjunction with Heartbeat.

According to lead developer Alan Robertson, "the Heartbeat and DRBD projects make high availability computing accessible to small- and mid-sized organizations for the first time, and this is really significant. It means that they can now afford a higher level of service from their systems than they are used to. For example, the low-end version of DB2 for Linux is about $1000, but to get redundancy you have to pay more like $25,000. Now it's possible to add the redundancy yourself with open source software and use the cheaper version if you need to cut costs. With a combination of Heartbeat and DRBD, you can get redundancy and replication of data, and save thousands."
Posted by Maria Winslow Joomla!
27 JUN 2006 14:14 EDT (18:14, GMT)
The final content management system among my favorites is Joomla! This free open source project is actually a fork from the once-beloved Mambo. My recommendation has been to follow the fork, since the vast majority of the Mambo development team initiated it. Original squabbles aside; the exceptional value of Mambo was in its technology team and user community.

The system, based on PHP and MySQL, was written for ease of use so that administrators need not be IT professionals. Mambo features a Web-based installation process, a WYSIWIG editor, access control levels, a media manager and support for over 20 languages.

A healthy third-party market has developed around the project, and a wide range of modules can be either purchased or downloaded for free.

Joomla! Features

• Free open source content management system
• WYSIWYG editor
• Easy to use
• Access control levels
• Banner management
• Templates
• Content versioning and archiving

Zope Corporation, the makers of Zope, was originally formed in 1995 in Fredericksburg, Va. to develop a classified advertisement engine for the Internet. The company released Zope as open source in 1998 and began to concentrate on providing customization services for the general-purpose content management system.

Zope Features

• Free open source Wb application server
• Out-of-the-box content management system
• Transactional support
• Includes an API for easier customization on Linux, Windows, and other operating systems with multiple Web servers and databases

The project Website hosts a very nice collection of documentation including: an entire book in .pdf format, an API reference for customizing Zope, tutorials and articles.

Free support can be found on the mailing lists. There are a few user groups worldwide, and they are listed on the project website. The Zope Corporation offers technical support for Zope, custom application development and managed Zope hosting services. The company also sells several pre-packaged solutions based on Zope, including a complete intranet/extranet system, a content publishing solution for media companies, a membership registration system and a replication/redundancy system for Zope installations.
Posted by Maria Winslow Another open source content manager
23 JUN 2006 14:15 EDT (18:15, GMT)
Here is another sure bet for an open source content manager: phpWebsite. One thing I really like about this project is that it is completely non-commercial and created by a university. Other educational institutions will find it particularly appealing for this reason, but the private sector will also like its flexibility.

phpWebsite is a free open source content management system developed by Appalachian State University in Boone, N.C. The project had its start in 2000 when Brian Brown, director of Electronic Student Services for the university, was tasked with organizing the web presence of over forty departments. With such diverse content, it was clear that he needed a professional quality content management system, but the commercial products were too expensive. Appalachian State had also been abandoned in the past by vendors of proprietary software, and Brown was not keen for it to happen again. It was important to Brown that they have control over the source code so that no third party could force changes that were not appropriate for the university. So they built it themselves. The result is an easy-to-use, modular, extensible web content management system that has been consistently among the most popular open source projects.

Because the university is publicly funded, Brown thought it was appropriate that their work should have some benefit to the public. phpWebsite was released under the L-GPL, which allows for the linking of proprietary software to its code. Two full time staff members maintain the codebase, and their work continues to revolve around functionality most useful for the university.

The main design goals are to make phpWebsite flexible and extensible. A modular design and the use of PHP make it easy to create custom functionality through drop-in modules, making it a platform for rapid web development. Several modules are included in the core installation, such as calendaring, email, a photo album, form generators, polling and the facility for website visitor interaction such as posting notes. The team is currently working to improve the documentation on the open API (application programming interface libraries) to make it easier to create custom modules. Third party modules are beginning to appear, and a few have spawned their own separate open source projects. The server runs on MacOS X, Windows NT/2000, BSD and Linux, and configuration can be done from any web browser. Even if you are not ready to run Linux for the server, you can take advantage of phpWebsite on a Windows server.

phpWebsite Features

• Free open source content management system
• Developed and maintained by Appalachian State University
• Easy to use, modular design
• Extensible, designed to allow developers to build their own modules
• Server runs on MacOS X, Windows NT/2000, BSD and Linux.

Free support for advanced users can be obtained via the project forums and mailing lists. Basic documentation is provided on the project website. Commercial support is available from at least two companies, with a range of services. ITWebSolution provides offsite hosting using phpWebsite and support for your internal installations. They also offer design templates that are used in phpWebsite to define the look. LACMedia provides installation, configuration and customization, along with custom module development and offsite hosting.
Posted by Maria Winslow Open source content management
22 JUN 2006 23:27 EDT (03:27, GMT)
I got a newsletter update from Bricolage today, and it got me thinking about open source contact management systems in general. This is a category that has seen especially good progress in terms of open source offerings, and I consider several of these content management systems to be obvious choices for any organization needing to save some money. I'll highlight my favorites, starting today with Bricolage.

Bricolage is a free, open-source content management and publishing system. The full set of features includes:

• Intuitive and highly configurable administration
• Workflow
• Permissions
• Templating
• Server-neutral output, distribution and
• Document management

It was designed to manage dynamic online content with multiple contributors for a complex website, but can be used to manage any online content. The product uses Perl, PHP, Apache, and PostgreSQL.

Bricolage began as an internal content management system for Salon.com. The company wanted to create a product from the code base, and looked for investment capital to fund a commercial product. When capital didn't materialize, Salon.com sold the code to their one customer, About.com. About.com continued work on the project, hiring some of the original developers. They released Bricolage under the Revised BSD license in 2001. Current users of Bricolage include Vibe Magazine, Spin Magazine, the RAND Corporation, and Comcast.

Bricolage Features

• Free open source content management and publishing system
• Replacement for expensive proprietary systems
• Easy to use, modular design
• Commercial custom development available from core developer

Bricolage inspired a glowing review from eWeek, which declared, "Bricolage is quite possibly the most capable enterprise-class open-source application available. The Web content management application features excellent administration capabilities, and it is highly extensible and capable of managing even the biggest and most complex Web sites." Comparable proprietary systems, such as Vignette and Interwoven, can cost hundreds of thousands of dollars per installation. Since Bricolage is free, it is feasible for managing internal content in a mid-sized organization. According to maintainer and lead developer David Wheeler, the quick success of the project was partly due to having early corporate support. Current users of the product also contribute code.

Kineticode, founded by Wheeler, offers a full range of commercial support options. Free support is also available from the community on the project mailing lists. Linux Journal ran a series of how-to articles in 2003 on Bricolage installation and configuration that are very helpful giving you a sense for what the product can do.
Posted by Maria Winslow Developer education is crucial for open source compliance
21 JUN 2006 16:49 EDT (20:49, GMT)
By now, you'd think that most developers and system administrators have gained a basic understanding of open source licensing, right? Well, no, actually. I am continually amazed at the lack of understanding in the developer community of the rules and responsibilities of open source.

Open source software has created a new need for technical workers to have a basic understanding of legal issues. In this break from the proprietary software world employees, who previously never needed to understand the implications of licensing and contracts, now have an unprecedented responsibility to follow rules that many organizations still don't fully understand.

Education is critical to any compliance effort. Most people using open source software are not well informed about the implications and about their responsibilities. Different licenses have different requirements, too, and many of these subtleties are not well understood. If you're not careful, you can wind up infringing on the GPL because an ill-informed developer used GPL code without anyone's knowledge.

The best way to mitigate this risk is by being proactive about making sure everyone understands the rules. Because all open source software can be acquired at no cost, there is a strong culture of "free as in beer" among practitioners. This may lead developers to give away their open source code modifications without thinking about the official policy, if one exists. There are times to make code available and times to keep it internal, but the point is that developers should not be making the decision.
Posted by Maria Winslow The entitlement culture of open source software
20 JUN 2006 21:52 EDT (01:52, GMT)
The difference between "free software" and "open source software" has always been a problem for me.

I recently read an article about IBM offering paid support for Eclipse. The tool is free, of course. When they did a survey, over 30% of developers expected the support to be free, too. Do these people have no concept of economics? I think we're looking at an entitlement society created by an unfortunate moniker.

And take Shorewall, a very popular open source project used to configure firewalls. Tom Eastep started the project in 1999 for personal use, and gradually expanded it to the popular tool it is today (it is very commonly used among system administrators). But he remained the primary source for code, documentation and support, despite his pleas for help. In 2005, in an open letter, he quit his leading role because of increasing frustration that everyone expected something for free without giving back. He eventually picked it up again, but where was his community? Have we created an entitlement culture by promoting the "free-ness" of open source software without pushing the responsibilities?
Posted by Maria Winslow Copyflex: a new model for open source
19 JUN 2006 22:09 EDT (02:09, GMT)
Is open source really the best licensing arrangement for both consumers and software companies? Is there something between proprietary and open source that will work better for both? Geoffrey Parker of Tulane and Marshall van Alstyne of MIT and Boston University think so. These economists have been working on research involving what happens in the space between proprietary and open source. Their research examined how both private and public interests were enhanced with a new blended licensing structure.

In a nutshell, what they found is this: Everyone benefits if software is licensed under terms that are restrictive (like a typical proprietary license) for a limited time, then shift to unrestrictive (like the GPL) after that. Parker and van Alstyne found that innovation increased when companies had this limited time of protection for their investment.

In fact, one of the most successful open source companies has essentially found its way around the GPL by using trademark law to maintain control over its product. Red Hat has undoubtedly pushed innovation in operating systems and increased overall rates of open source software adoption, while at the same time making money. By contrast, consider Linux companies that were once popular but have since faded. One simple reason is that their followers were able to use a completely free version that was just as good as the paid-for version, so they did. With a shortage of revenue, these companies were unable to continue to innovate and promote Linux like Red Hat, and they faded from the scene.

Both new and existing companies have been trying to find their places on the open source scene, and it has been a difficult task for many. Could it be that we just haven't narrowed down quite the right model?
Posted by Maria Winslow How to keep your options open
18 JUN 2006 21:45 EDT (01:45, GMT)
Some organizations will find that they are able to make wide use of open source software; while others will find few suitable migration candidates. Some of this discrepancy will be due to differences across industries. For example, industries that tend to make conservative technology decisions are likely to have more legacy systems that are difficult to migrate. But even within the same industries, technical managers will find a range of potential migration scenarios. The differences in experience will depend on the platform-neutrality of the applications in use.

Those organizations that have made heavy use of Web-based technologies and kept it platform-neutral will have the most migration opportunities now. When the Web browser began to replace the operating system as a computing platform, some technical managers understood that this was the wave of the future. They insisted on browser-based applications wherever practical, both from vendors and internal development staff. If you are one of these managers, then your vision will pay off when you look for ways to migrate to Linux, especially on the desktop.

But it's not too late to keep your options open for the future. You can maintain your flexibility by making it a policy that all new applications be platform neutral and employ open standards whenever possible. You have complete control over this for applications developed by your internal staff, of course. But what if you only have Visual Basic programmers on staff? They will cost you too much lost opportunity in the long run, and should be either retrained or replaced. By continuing to develop exclusively for Windows, you will lock your organization out of significant potential savings for years to come. The expenses you incur now by adjusting your staff skill set will keep you from writing more applications that will restrict your options in the future.

Making platform neutrality and open standards a requirement for third-party applications is also becoming more and more feasible, especially as Linux spreads. Not all vendors are ready for this, of course, but the discussion should be a part of all future purchases. Make it clear that you want more flexibility in future releases. Vendors will begin to comply when they get enough pressure from their customer base.

As you examine your computing environment for ways to bring in Linux, it's important to examine the lifecycles of your platform-specific applications. Whether or not you are able to port these to platform neutral solutions over the next few years will affect the extent of possible Linux use. Decisions made now will still be with you after ten years, so it's an issue worthy of serious consideration.
Posted by Maria Winslow