The COVID-19 pandemic has changed the way we live and work in a short time. A third of the world’s population is now on some form of a lockdown, millions of people are working from home, and businesses around the globe are scrambling to respond to business continuity challenges.
The surge in remote workers means remote-access capacity must drastically increase to meet demand. With IT infrastructure being tested in unprecedented ways, system agility becomes vital to keeping businesses up and running.
Capacity elasticity has always been key to the design of Citrix ADC. After all, many of our customers have highly seasonal traffic pattern (for example, retail on Black Friday or CPAs around tax time). Over the years, we’ve developed unique technologies that enable a high degree of capacity elasticity to respond rapidly to increases in traffic loads. In this blog post, I will highlight licensing technologies available with our ADC product line and how customers use them to rapidly respond to changing conditions:
Pay-As-You-Grow Platform Licensing Technology
Most ADCs today have fixed capacity. Expanding it requires a rip-and-replace. Such forklift upgrades add delays and risks to business operations. Our Pay-As-You-Grow technology supports multiple licensing levels for the same hardware. Customers buy what they need today and can upgrade when they require higher capacity.
Consider Citrix ADC MPX 15000. While the base model starts with a 20Gbps license level, the hardware platform has the capacity to expand up to 120Gbps. You can buy the base model and add capacity as needed. It’s as simple as applying a license upgrade, which will unlock additional hardware resources in the system.
Flexible Pooled Subscription Licensing
With traditional perpetual licensing, licensed capacity is locked into a specific system and can’t be moved, even if the system isn’t being used. Citrix introduced Pooled Licensing to address this limitation. With Pooled Licensing, capacity licenses are decoupled from the underlying platforms and are managed as a single shared pool. You can allocate the pooled capacity dynamically to any ADC at any time. If the capacity for a system is no longer needed, you can return to the license pool or move it to other ADCs.
The pooled capacity licenses can be used by any Citrix ADC form factor — hardware platforms such as MPX and SDX or virtual platforms like VPX, CPX, or BLX. The licenses can be used in on-prem deployments or in the cloud with services like AWS, Azure or GCP. Pooled licensing provides maximum flexibility and license portability across the entire ADC product line. The pooled licensing is managed by Citrix Application Delivery Management (ADM), which you’ll learn more about below.
Let’s consider a business that has 10 Citrix ADC VPX devices, each with a 10Gps throughput license. Each VPX typically uses 5Gps throughput in normal operations. With traditional perpetual licensing, each VPX can only expand 5Gps to 10Gps during an emergency. Pooled licensing allows for consolidation of all 100Gps licenses (10Gps each from 10 virtual ADCs) into a single pool. During normal operation, 50Gps is allocated to the 10 VPX instances, and the remaining 50Gps is unused. During an unforeseen event, like the current pandemic, the additional 50Gps capacity can be deployed where it’s needed. For example, you could apply 25 Gbps to two VPX instances to support remote access, leaving the other devices unchanged.
Hitless License Upgrade
While Pay-As-You-Grow and Pooled Licensing provide capacity flexibility for rapid response, Hitless License Upgrade technology minimizes the impact to customers’ user experience when changes happen.
In general, capacity upgrades, require a system reboot, usually during a scheduled maintenance window to minimize disruption to user traffic. But this type of delay might not be acceptable when the systems are overloaded. The Hitless License Upgrade feature for Pooled Licensing allows for capacity upgrades anytime, without requiring a reboot, so you can make capacity changes instantly.
Application Delivery Management Platform
Citrix ADM acts as the licensing server for pooled licenses and provides a rich set of tools for managing and visualizing the ADC infrastructure. The ADM license dashboard shows a snapshot of what capacity has been deployed and where. The infrastructure and app dashboards give you all the information you need to make quick decisions. For example, you can leverage the infrastructure dashboard, shown below, to identify hotspots across your application infrastructure and add capacity to those hotspots.
You can also use Citrix ADM to automate migration from one location to another. For example, if an app running in your on-prem data center needs to be moved to a public cloud to support a surge in work-from-home traffic, you can use the StyleBooks Configuration Builder to simplify migration of the ADC configuration from the on-prem device to a new instance in the cloud.
You can also use Citrix ADM to set up GSLB to allow traffic spillover. For example, when the connection limit or throughput limit of the primary site has reached a defined threshold, you can forward connections to the secondary or to backup servers elsewhere.
It’s hard to predict the future, but you can prepare for disruption and minimize its impact. Being prepared can mean the difference between your operations coming to a halt and your business continuing as usual. Citrix enables the capacity flexibility you need to respond quickly to change, whether it’s due to a rush of holiday shoppers or a global pandemic that forces you to transition all your employees to remote work. Learn more about Citrix ADC.
