By Arvind Kandula, Principal Product Manager at Citrix Systems (ADC)
At Citrix, we take the voice of our customers as the barometer in everything we do.
Our status as an AWS Advanced Technology Partner with AWS Competencies in Networking and Digital Workplace allows us to have regular conversations with our customers—many of whom start with the topic of architectural planning.
We noticed there is more of a focus on building cost-optimized solutions as customers expand on Amazon Web Services (AWS) to enhance their success. They start in one region and want to replicate across others.
In recognizing that every customer can be in a different phase of their cloud adoption, we often find ourselves providing guidance around the following use cases:
- Use Case 1: Expanding from on-premises data centers to AWS.
- Use Case 2: Shifting away from on-premises to AWS.
- Use Case 3: Starting out on AWS to serve their users globally.
This post captures some of the advice we offer customers about how Citrix ADC can help in each use case. We’ll explore details about the best ways to get started with this comprehensive application delivery and load balancing solution for monolithic and microservices-based applications.
With Citrix ADC, customers can deliver a better user experience, on any device, from anywhere.
Use Case 1: Expanding From On-Premises to AWS
In this use case, customers have their on-premises data centers active and are building their Amazon Virtual Private Clouds (VPCs) in a parallel building.
They want to replicate their applications across different VPCs in different regions seamlessly. At the same time, they look for maximum uptime; if even one deployment fails, the other should serve the traffic with no service abruption to customers.
Citrix ADC High Availability Across Availability Zones
The architectural guidance provided by Citrix to these kinds of customers is to adopt Citrix ADC High Availability across Availability Zones. This is an Active/Passive deployment with one primary and one secondary Citrix ADC instance across different AWS Availability Zones.
If the primary instance goes down or becomes unreachable, the secondary instance takes over and provides high availability. This ensures no downtime for the application traffic.
The seamless failover leverages Elastic IP addresses (EIP), where the EIP assigned to the application VIP migrates from the primary to the secondary instance. Because this is just an IP mapping change, failover happens very quickly. This can improve resiliency and agility of the applications deployed.
Below is the sample architecture of high availability deployment across AWS Availability Zones. AWS CloudFormation templates in Github can be leveraged to replicate the deployment.
Figure 1 – Citrix ADC High Availability across Availability Zones.
For customers who cannot use EIP, due to their architectural requirements or their application being internal, Citrix ADC high availability across Availability Zones with private IP can be leveraged.
In this scenario, private IPs can be used as VIP. During high availability failover, VPC route pointing to the primary elastic network interface (ENI) migrates to the secondary client ENI.
Citrix also recommends customers use Citrix ADM to define their ADC configurations for their applications using StyleBook templates. These can be reused as they replicate their applications in other regions. This can simplify their application deployment and reduce time to market.
Use Case 2: Shifting Away from On-Premises to AWS
Some customers are moving their users’ applications from on-premises data centers to Amazon VPCs and want to decommission their on-premises deployments in the future.
Many of these customers have unpredictable traffic patterns, driving them to a more flexible design where they don’t pay for overprovisioned resources. Instead, they seek an environment that will automatically fluctuate with changing demand.
Citrix ADC Autoscaling Solution
These customers love the concept of the Citrix ADC Autoscaling solution. This allows them to start with a single node in one zone, which can expand to multiple zones and multiple nodes.
This is an Active/Active deployment where every Citrix ADC instance is active. If any ADC node goes down or there is a requirement for more capacity, a new ADC instance will be provisioned and configured immediately.
If an Availability Zone becomes unreachable, the other ones will step up and provide the service, seamlessly.
The ability of this solution to expand and contract with changing demand helps put a check on costs, as capacity is continuously mapped to demand with no waste of resources or expense.
This solution removes the burden of capacity planning so there is one less thing for the business to worry about. Below is the sample architecture of autoscaling deployment depicting the use of Citrix ADM, ADC, and AWS services.
Figure 2 – Architecture of autoscaling feature of Citrix ADC using ADM.
Use Case 3: Starting Out in AWS to Serve Users Globally
Many customers are bound by regulations to store content in specific regions, and they want to direct user requests to the closest/best performing data center to guarantee the best user experience.
Citrix ADC GSLB solution
In these scenarios, Citrix recommends the Citrix ADC GSLB solution. It’s a great fit for customers who want to manage and control the traffic flow between multiple separate physical locations that are geographically dispersed. This can help to control load or ensure business continuity.
Global server load balancing (GSLB) is based on DNS, and the Citrix ADC often serves as an authoritative name server for the domain. The solution can be configured such that the data centers are in an Active/Active setup to share the load and ensure users connect to the nearest resource.
Or, it can be set up in an Active/Passive manner, for disaster recovery scenarios or maintenance. The setup depends on what customers’ need to achieve, but Citrix offers the flexibility to choose.
Below is the architecture of Citrix ADC GSLB deployment depicting ADC GSLB nodes and ADC LB nodes in different AWS regions.
Figure 3 – Architecture of Citrix ADC GSLB deployment.
Together, Citrix ADC and Citrix ADM enables IT teams to utilize the public cloud resources they need so they can maintain application performance—and keep costs down.
In addition, Citrix ADC and ADM provide integration with automation and cloud orchestration systems to support application rollouts with self-service capabilities.
Citrix ADC on AWS gives customers the flexibility to simplify traditional and new application delivery with a hybrid app delivery infrastructure.
For more information, please visit the Citrix ADC on AWS website.
The content and opinions in this blog are those of the third-party author and AWS is not responsible for the content or accuracy of this post.
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Citrix is an AWS Advanced Technology Partner that transforms how businesses and IT work. As an extension of their ongoing collaboration with Amazon, Citrix delivers networking and desktop virtualization solutions on AWS.
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