Carrier Grade Linux (CGL) started as a telecommunications infrastructure building block, but its strong availability, scalability and service response features are driving its adoption in corporate IT environments, says Bill Weinberg, open source architecture specialist for Open Source Development Labs (OSDL), in Beaverton, Ore. Along the way, it's being enhanced to work with virtualization and blade servers, too.
In its work on CGL, a set of specifications for Linux standards, OSDL has pioneered the move to open architectures. "I think some people imagined that Carrier Grade was winding down, that people had reached a level that was satisfactory, and that was that," says Weinberg. "But it's a key ingredient in a dynamic market, and it's moving ahead in fulfilling convergence and other new requirements for quality and service."
Weinberg describes CGL's new roles in the enterprise and its synergy with virtualization and blade servers in this interview. He also discusses new developments in the Linux kernel.
SearchOpenSource.com: Where is Carrier Grade Linux, now in version 3.2, being used in the corporate data center?
Bill Weinberg: Its strong play has been in telecommunications. We're beginning to see telecommunications and networking domains outside heavy iron telephony look at Carrier Grade as the basis for their applications and platforms. Industries like aerospace, defense and medical are looking at this as a more reliable baseline to build on.
In the enterprise, Carrier Grade Linux is being embraced for very mission-critical, business-critical systems. It's an option for the core and edge, where they're today using clusters that have basic redundancy, but don't -- for example -- have very rapid-fire failover or a lot of hardware-monitoring integration. Here, the additional redundancy and hardware features that Carrier Grade brings, over and above what off-the-shelf enterprise Linux brings, are very attractive.
Isn't Carrier Grade Linux moving from its traditional architectures, like appliances, to new ones, like blades?
Weinberg: Yes. We're seeing an expansion of the role of Carrier Grade in a flavor of embedded Linux on a blade. The blade might be running, say, a PowerPC architecture, so you wouldn't necessary see it being Carrier Grade. Up to now, you'd see the shelf controller above the server being Carrier Grade, but there's a trend toward wanting Carrier Grade from top to bottom in the system design.
At conferences, I've heard speakers advocating a mix of Carrier Grade Linux and virtualization. What's going on in these areas?
Weinberg: People put those two topics together when discussing multiple instances of highly available systems running on virtualized hardware. The normal way people think about virtualized hardware is that it's a single system running multiple instances of an OS, and that would be the way you would start.
However, as you see the expansion of IP-based media services, of telephony, of voice out to other kinds of media, the carriers and operators are looking at Carrier Grade Linux architectures.
Carrier Grade plays well in media gateway services, so you could have all of the content availability servers and telephony systems in the middle running on virtualized servers. Then, you balance a load across a set of virtualized servers, so that any one instance of an OS -- let alone the applications deck on it -- doesn't really need to know whether it's running on one piece of hardware with multiple sister instances or whether it's running across multiple pieces of hardware.
So, as a load-balancing capability, Carrier Grade Linux partnered with virtualization is important. Frankly, [virtualization] is a performance enhancer. One of the reasons today that it's hard to provide quality service is the huge variability of load on a network that wasn't designed for QoS [quality-of-service] but was designed for store and forwarding. A way to get around that is through virtualization coupled with Carrier Grade Linux. They're a natural fit for each other.
What is a key indicator that Carrier Grade Linux may be a good fit for a corporate IT environment?
Weinberg: It's attractive if you're looking at massive data center applications with a lot of systems and a lot of throughput; in places where you really do want five or six nines of up time.
Carrier Grade has mostly been deployed in the management role in systems architecture. Its role has been to manage the availability of failover of network nodes and other resources.
We've also seen the desire to put Carrier Grade Linux on the nodes, which are classically the points of failure, to make them more reliable. Some of the attributes of Carrier Grade in reliability have to do with things like rapid re-boot, better hardware interfaces, etc.
Will the security technologies being developed for Carrier Grade Linux spill over into the enterprise?
Weinberg: I think Carrier Grade Linux's security improvements have been moving in tandem with what's going on in the enterprise, but often the channels of access are different in carrier environments. Some of the demands for security in a carrier environment are unique, because it resides on private networks that have different types of access. Even so, a lot of them are shared paradigmatically with what you find in the enterprise.
The security paradigm for Carrier Grade was introduced with the 3.0 specifications, and it's undergoing a review and revision right now. I'll note here that the reliability capabilities that Carrier Grade is looking at now relate directly to security, people tend to think of security in terms of 'reach out and touch me' exploits, but in contexts with availability guarantees, denials of service are every bit as important.
Is Carrier Grade Linux driving Linux adoption in the mainstream business market?
Weinberg: I think Carrier Grade is part of, dare I call it, an end-to-end adoption trend. In terms of broad adoption, we've seen Linux grow from being used in utility computing at the edge to generic data center applications to real core enterprise applications, and most recently business-critical applications. With that latter trend comes Carrier Grade for core access and network core and access Internet applications.
Behind the scenes, however, Linux probably has its greatest market share advantage; something like 30% to 35% embedded designs are today going out with Linux.
Linux is making headway everywhere, but that ubiquitousness isn't always visible. Linux is embedded in your wireless routers, your mobile phones and more. There are very good odds that you're using Carrier Grade Linux anytime you pick up the phone. That's absolutely certain for international phone calls.
Where is virtualization coming up in the development of the Linux kernel?
Weinberg: Starting several versions ago, the virtual environment began being treated like any other architecture in the kernel. Different elements of the community -- corporate and technical -- decided collectively that virtualization was a good place to be. So, kernel developers moved up quickly from a series of patches and projects to separate hypervisors, and virtualization became part of the standard kernel tree.
That was an important statement in two ways, indicating how quickly virtualization became mainstream and how much demand there has been for virtualization in the kernel. People aren't going to virtualize something that isn't already mature, and the demand showed that Linux is ubiquitous.
The kernel community showed a lot of maturity and foresight in embracing virtualization, one of the killer technologies out there.