The Citadel Groupware Server
The time has come to consider moving that expensive, high-maintenance Windows system to a sleeker, more robust Linux system. The gap analyses have been done, the meetings held, the presentations complete, and now it's go time. Although installing and configuring a Linux server back end can be challenging, we all know that users aren't going to care about that. What they want is uninterrupted functionality so they can continue doing their jobs. Although migrating users from applications such as Microsoft Office to OpenOffice.org is generally an intuitive task, the 800-pound gorilla that's keeping you up at night is e-mail and groupware. How are you going to provide and manage Microsoft Outlook-like functionality to the masses? In a word, Citadel.
One of the understated wonders of the Free and Open Source Software world is the Citadel Groupware Server (www.citadel.org). Controlled by a single developer, Citadel started life in 1987 as a UNIX version of the already-existing Citadel-CP/M application. Almost 20 years later, the modern-day Citadel boasts all of the functionality of a mature groupware server. One of the miracles that Citadel can perform is providing all of the most-used functionality of Microsoft Exchange with little fuss and and even less cost.
Many modern organizations are coming to the realization that their IT budget is largely controlled by Microsoft's licensing fees and hardware requirements. Although organizations can prepare for some of these costs, many are looking at Vista with trepidation. Although the hardware requirements for Vista aren't obscenely over the top, many organizations still will need to upgrade their hardware in order to run it. And, sooner or later, run it they will. The hardware upgrade cycle is a never-ending source of pain for some organizations, because not only do servers and server software need to be upgraded on a somewhat regular basis, but untold numbers of workstations also need attention.
Depending on the size of your organization, your Microsoft Exchange server might be the most robust server in the closet, and finding a suitable replacement for Exchange is quite often a show-stopper. Citadel is a groupware solution that allows organizations not only to avoid upgrading software, but it also runs on a significantly lower-powered machine, thus breaking the hardware upgrade cycle for years to come.
It's always good practice to install and test everything on a test server before moving it into a production environment. Swapping out your mail server is certainly no different, and you should keep your Citadel testing as far away from your production system as possible. Obtaining and configuring Citadel is several orders of magnitude easier with an Internet-connected server, however, because you can avail yourself of the Easy Installation process.
As of this writing, the most current version of Citadel is 6.84. I highly recommend a trip by the Citadel site in order to obtain the most current version of the server and the most current version of the installation instructions. Our testing environment consisted of Debian Sarge with a 2.6 kernel running in VMware Player 1.0.2. For no particular reason, we selected the Web server installation option, but virtually any installation category should work, as Citadel installs everything it needs. In the past, we have installed and run Citadel on a Debian Sarge server proper, and in both cases the installation was flawless.
I cover the Easy Installation method here not only because it's easy, but it's also fairly undemanding on resources and therefore quite likely that anyone can make use of it. Just about the only requirement for the Easy Installation method is a working—and preferably fast—Internet connection.
The Easy Installation method requires the toolchain, or build environment, to be present on the target platform. In addition, curl (or wget) is required. If you'd like to support SSL connections to the server, you also need libssl-dev. On a Debian system, use the following command to install or verify your build environment:
apt-get install build-essential curl libssl-dev
Before installing, it is worth noting that Citadel is designed as a black box system running on your server. Part of that black box means that Citadel authenticates logins against its own user database and not against your system user database (typically /etc/passwd). If you'd like Citadel to authenticate against your system user database, you must export the IS_AUTOLOGIN variable to the environment prior to running the Citadel install, like so:
Now that the environment is set, it's time to kick off the Easy Install with the command:
curl http://easyinstall.citadel.org/install | sh
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide