Specsavers sees clear benefits in open source

...is included in several widely used Linux distributions. Implementations exist for BSD variants, proprietary Unix distributions, Mac OS X and even Windows.

"We introduced [Specsavers] to OpenLDAP, and they liked that," said Taylor. "They migrated everything out of their proprietary directory service into OpenLDAP and now run all of their user-management functions from that."

Samba, an open-source re-implementation of the SMB/CIFS networking protocol, is standard on nearly all distributions of Linux and effectively allows integration with Windows Server and Active Directory domains. The software was important to the project, given Specsavers' heterogeneous IT environment, and particularly its Windows workstations.

"One of the reasons for making the fully open-source server environment closely resemble a Windows environment is the presentation to the Windows desktop. It was important that the presentation of the servers didn't touch that," said Taylor. "The other reason was that many of Specsavers' engineers are familiar with Windows-style networks on the server side."

Fortunately, configuring Samba to imitate Windows environments is "perfectly straightforward", according to Taylor.

The third piece of the puzzle was the graphical interface for the front end. Specsavers selected Gosa, a PHP-based graphical administration tool, developed as part of the city of Munich's comprehensive deployment of open-source software, to help manage the deployment.

Gosa uses a security model along the lines of access-control lists (ACL) and allows administrators to install, reinstall and manage computers and users on a large-scale network.

Gosa can also be accessed by users to manage their own passwords or other information. The tool allowed Specsavers to decentralise role-based access control, giving application or business-process owners the ability to create, manage and delegate groups on their own.

Taylor said he believes it's significant that Gosa has emerged out of one open-source project (Munich) and is now being reused by other large organisations.

"Ten or 15 years ago, you had the basic open-source elements, but now they are being used in the real world, in real businesses, and that is throwing up new requirements. You need the tools to manage this stuff," Taylor said. "The remarkable thing is: those tools are being developed. Munich has shown this process in action."

Design challenges
The project's biggest challenge was presented by the wide geographical dispersion involved, covering multiple time zones, said Taylor.

"This brought in a lot of design challenges. For instance, what's the best way of replicating data?" Taylor said. "Specsavers is no longer a single-country business. In the past two or three years, they've bought substantial chains in northern Europe. They're the biggest opticians in Sweden now. This meant collecting data from different parts of the organisation and centralising them."

On the one hand, in the final system, all the different parts of the global business are centralised into a single directory tree. At the same time, the data is replicated to each country.

The open nature of the software used has led to improvements in compatibility, which has allowed some significant simplifications in Specsavers' network.

Previously, the company needed to maintain several different sources of authentication, one for proprietary Unix machines and others for Windows systems or boxed appliances, such as proxy servers or firewalls.

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"Centralising meant that each of those has been integrated to use the same source of authentication," said Taylor. "It's cross-platform [and] cross-device. If a staff member is hired, they now don't need to be added in three or four different places — just one."

"You can get this kind of centralisation if it's purely a Windows domain, for instance, but, once you bring Unix in, it's no longer simple. With open source, it's equally comfortable with Windows, Solaris or whatever," Taylor said.

Simplification
IT director Khan had balked at the prospect of the licensing complications that would have arisen from expanding rapidly with a proprietary infrastructure. Open-source software eliminated that problem.

"If you want to throw a few more thousand machines in there, you can just do it," said Taylor. "There is a whole layer of bureaucracy that it takes out. You don't need to worry about compliance or licence tracking for these deployments."

Specsavers is approaching open-source software as a strategic investment that will give it control over the future direction of the company's infrastructure. Open source means that Specsavers can choose when to upgrade and can take its choice of software packages, because they're all interoperable. "They're not locked into any one platform choice. They can choose what's the best file server, the best email server or whatever," Taylor said.

While this is the biggest deployment of its kind in the UK to date, according to Taylor, more UK companies are beginning to show a serious interest in open source. The only thing holding them back is "inertia", Taylor said. Other UK companies with a board-level interest in open source include Malmaison and Unilever.

"The beauty of Specsavers is: we're finally seeing companies drive this from the top down. It was a strategic choice, not via the back door, not a few techies in the IT department installing Apache," Taylor said.