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Even as applications move from traditional data centers to the cloud, server load balancing continues to be a core element of IT infrastructure. Whether servers are real or virtual, permanent or ephemeral, there is always a need to intelligently distribute workloads across those multiple servers.

But there remains a chronic gap in the ability to reliably distribute workloads across multiple clouds, multiple data centers and hybrid infrastructures. The result is poorly distributed workloads and degraded application performance that could be avoided if workloads were better managed globally. In short, there is a need for better global server load balancing (GSLB).

Also referred to as application-delivery controllers (ADCs), load balancers are widely deployed in data centers. Their function is to distribute workloads to back-end servers, thereby ensuring optimum use of aggregate server capacity and better application performance.

Providers including Citrix, F5, Kemp Technologies and Radware occupy the traditional load-balancer market. Their hardware ADCs have been the go-to solutions for infrastructure and operations teams for some time. Recently, software-based ADCs from these vendors and software-only solutions such as HAProxy, Nginx and Amazon ELB have emerged as enterprises have moved applications to the cloud.

Organizations can implement multi-data-center, multi-cloud GSLB using one of two basic approaches. The first is to use a traditional managed-DNS provider for basic traffic management. It has the advantage of being easy to implement, low in cost and reliable, requiring no capital outlay. Unfortunately, it offers only minimal traffic-management capabilities such as round-robin DNS and geo-routing. These approaches fail to prevent maldistribution of workloads because they use fixed, static rules rather than basing traffic routing on the real-time workloads and capacity at each data center. For example, geo-routing can only ensure that users (and their workloads) are sent to the geographically closest data center. It cannot account for uneven distribution of users geographically, local demand spikes or server outages in a data center.

Many ADC vendors offer their own purpose-built DNS appliances that have a tighter integration with their load balancers to address these limitations. This is the second basic approach. These appliances can make traffic-management decisions on the basis of actual use levels at each data center by receiving real-time load and capacity information from the local load balancers.

The benefit is overshadowed by its tradeoffs, which many enterprises find unpalatable:

Consequently, most enterprises that have deployed data center load balancers arent using the GSLB functions available from their load-balance vendor. Those that have deployed GSLB functions are open to replacing them with a better solution. A superior approach is a cloud-based, managed GSLB solution that uses real-time telemetry from load balancers to make intelligent traffic-management decisions.

GSLB is best delivered as a cloud-based managed service. The core attributes and advantages of such an approach are as follows:

Its now possible to enjoy the best of both worlds: a globally performing, reliable managed DNS service and advanced traffic-management capabilities that were previously available only with proprietary ADC solutions. This combined offering provides new opportunities for enterprises to prevent maldistribution of application workloads and deliver better overall application performance as well as a better, more consistent end-user experience.

Jonathan Lewis brings to NS1 over 25 years of IT-industry experience comprising product management, product marketing, customer service and systems engineering. Jonathan has played key roles contributing to the success of several industry-leading companies including Nortel, Arbor Networks, and SSH Communications Security (SSH1V). He holds BS and MS degrees from McGill University, an MBA from Bentley College and CISSP certification.

Global Server Load Balancing Moves to the Cloud was last modified: June 1st, 2017 by Jonathan Lewis

Link:
Global Server Load Balancing Moves to the Cloud - The Data Center Journal