Open Ticket for Continental

Continental Airlines pushed the envelope when it moved its automated ticket-reissue application to an open-source software stack that included a 64-bit MySQL database server.

Continental Airlines Inc. encountered a bit of turbulence last year when it decided to shift the ticket-reissue application it had built for Unix-based servers to a full open-source software stack with a 64-bit database server.

There were no 64-bit editions of some of the key drivers and software products that the Houston-based airline needed for the application. So developers had to trek to Hewlett-Packard Co.'s service center to test and certify the drivers to run in 32-bit native mode on the 64-bit HP Linux systems.

Continental had to launch the application in September with the MySQL database servers in 32-bit mode and wait about five months for the 64-bit edition of HP's Serviceguard for Linux, which would provide the high availability it wanted. Within the next three weeks, the company expects to move its clustered 64-bit database servers from the lab to production, says Michael McDonald, director of technology.

Even before that happens, the application has been paying dividends on the open-source stack. A ticket-reissuing process that once took highly experienced agents an average of 20 minutes to complete can now be performed by customers visiting Continental's Web site. Later this year, customers will be able to access the application through self-service airport kiosks.

Moving from an ad hoc manual process to the Unix-based application running on 450-MHz HP NonStop servers initially cut the average transaction time to 15 seconds. Switching last September to faster Opteron-based HP servers for the database and Xeon-based boxes for the application and Web servers, all running on Linux, sliced the time to two seconds, according to McDonald.

Although the airline's approach may not be entirely unique, it's hardly commonplace among well-established corporations. In an IDC poll of Linux users released last July, just 27% of the respondents said they run databases on Linux. And with Continental, it's not only a database but also will be a 64-bit MySQL database running on Linux.

"They're leading-edge. You're not even talking about hundreds of companies that are using 64-bit MySQL," says Gartner Inc. analyst Donald Feinberg.

In comparison, the Apache Web server and JBoss application server that Continental selected are far more popular choices. Meta Group Inc. analyst Thomas Murphy says many of his clients are deciding they don't need or want all of the J2EE technology and are opting for open-source stacks that are faster to develop on and to deploy.

But the use of a full open-source stack tends to be less prevalent in corporate IT development shops, according to Daryl Plummer, a Gartner analyst. "There are a lot more successes for people who have adopted parts of the open-source stack," he says. "It's usually more for fringe or Web applications, but it's moving more and more toward the critical ones every day."

Becoming Mission-Critical

Continental's ticket-reissue application didn't start out as mission-critical. After all, it didn't even exist when the development team started the project. But the application now provides an audit trail for $400,000 in ticket reissues per day, according to Michael Natale, the airline's chief technology officer.

Natale says the application also gives customers a consistent price, whether they use it through the Web site or call an agent who accesses a custom version of the application through a PC.

If Continental had taken the traditional approach, it would have developed the application for its mainframe-class IBM Transaction Processing Facility (TPF) system using assembler code and made the application available only to agents using green-screen terminals. Instead, the project team wrote the application using Java technology, knowing that it would work well with the company's Unix platform and afford more options at the presentation layer.

The developers initially wrote the application for the built-in software stack of HP NonStop servers but soon found that the package was "overkill" for their needs, Natale says. "The total cost of ownership didn't warrant keeping it on that [proprietary] platform when the same availability and uptime were available with open-source technologies," he says. "We're an airline in an industry with tough, lean times right now, so we're trying to do things as efficiently as possible."

Continental's developers had also found the 450-MHz processors to be "a handicap" for running the Java code, says McDonald. "Java relies on the speed of the processors to execute the code base," he says. "The faster the processor, obviously, the faster your code's going to execute."

Swapping out the proprietary database, application and Web servers for open-source alternatives running on Linux went smoothly. And with support from HP and Red Hat Inc., McDonald didn't view the Linux decision as particularly risky. He says he had already witnessed continuous uptime of as long as 300 days while running Linux on development machines.

"The platform is mature enough now for enterprise applications," Natale says.

Continental now runs 10 dual-processor HP blade servers for the application and Web servers, and a hardware device load-balances them. Running on the cheaper commodity blades allows the company more flexibility to expand its server farm if transaction volume starts to spike. The IT department merely needs to plug in a server and run a script to install Linux, JBoss, Apache and the application. "It's ready to go in under four minutes," says McDonald.

For the database servers, Continental needed more-powerful boxes and opted for three quad-processor HP ProLiant servers, with the vendor's Serviceguard for Linux for high availability. "We assume that whenever the application server's available that the database should always be there," McDonald says.

Continental uses the database for persistence, through objects stored in the server. When a client makes a request, business logic at the application server level takes over and calls the database. The database, in turn, makes an average of 20 calls to the TPF system to retrieve the information.

A price is formulated and displayed to the customer. No additional processing is needed, regardless of whether the customer accepts or rejects the price, since Continental simply reads the state of the object from the database, McDonald notes. Changes are then committed to the TPF system, and the ticket is reissued. Or, if the customer has rejected the price, notations are made in the TPF records.

Plans call for the next iteration of the application to be able to calculate refunds. Developers will merely extend the current application architecture to do so, McDonald says.

By then, Continental hopes to have resolved a prickly issue over pricing with Electronic Data Systems Corp., which manages its data centers. EDS wants to view the quad-processor database servers as midrange boxes, and Continental thinks they should be viewed more like Windows servers on commodity hardware.

"The more Linux systems that you get into your data center, the less it costs per server to maintain," McDonald says. "Once you pass a certain point, the cost per server goes down tremendously. So it's just a matter of time before you get enough servers in the data center to make it economically feasible."

Finding More Uses for Linux

But the pricing debate isn't stopping Continental from expanding its Linux environment. A "flight farming" project running on open-source software polls the ticket database to pull out duplicate passenger-name records, Natale says.

Continental and EDS are also in the process of partitioning the TPF mainframe and moving some subsystems to a distributed environment of cheaper commodity Linux servers, McDonald says. The subsystems include pricing, scheduling and seat inventory.

"The TPF systems have been taxed out so much in the last few years that we're running out of capacity on some of those mainframes," McDonald says. "You have to move some of that off [the mainframe], or at least distribute it."

Continental is following the lead of companies such as Sabre Holdings Corp. and Cendant Corp., which have already moved some processing off their mainframes. With so many customers shopping for the best fares on Web sites, travel providers are looking for more cost-effective ways to provide those services.

"It's free for people sitting in their living rooms to click around," McDonald says, "but somebody has to pay the price for those transactions—and it's us."

Money-generating transactions, such as booking and ticketing, remain on Continental's tried-and-true mainframes.

Even though the more stable 2.6 Linux kernel is now supported by the most popular commercial Linux distributions from Red Hat and Novell Inc., many companies remain cautious about migrating important systems to the open-source operating system.

Gary Hein, an analyst at Burton Group, says clients tell him, "What's the motivation for me to put my neck on the line, when Oracle on Solaris is the core of my business and it functions just perfectly?" But he also finds that once users have a good experience, they're more inclined to take the plunge again.

"Success breeds success," Hein says. "They're hesitant to do the first one. But after they do, they say, 'Wow. That's hard not to do.' "

Continental developed and operates its ticket-reissue application on a full open-source stack from the MySQL database to the application and Web servers, all running on Linux.
Automated Ticket-Reissue Architecture
Source: Continental Airlines Inc.

Copyright © 2005 IDG Communications, Inc.

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