With the rapid evolution in digital dimensions, hybrid cloud environments have gradually started finding their way into IT infrastructure in businesses. However, operational aspects are complex in managing resources on-premise and in the cloud, so DNS or Domain Name System service is a backbone for network communication. Even in a well-sophisticated setup of clouds, without a solid and sound DNS strategy, performance and security issues can be encountered.

At Centric, we recently faced this challenge head-on. We aimed to create seamless DNS name resolution across our on-premises and public cloud environments, ensuring everything worked smoothly regardless of where resources were located. But as anyone working in hybrid infrastructure knows, it’s rarely as simple as it sounds.

The Challenge: Bridging the Gap Between On-Premises and Cloud DNS

One essential requirement for this project was to create a DNS solution that not only ensures seamless name resolution across hybrid environments but also directly supports business-critical objectives, such as reducing operational complexities, minimizing downtime, and enabling faster innovation cycles. These elements are key to maintaining competitive advantage in today’s dynamic markets.

We also wanted to leverage native cloud services as much as possible to keep operational costs down and simplify management. Given that most of our cloud infrastructure is hosted in Microsoft Azure, the Azure Private DNS Resolver was a natural choice for building the foundation of this DNS solution.

Designing the Solution: Separating Environments While Ensuring Connectivity

Initially, we drew inspiration from a Microsoft technical community blog, which laid out an ideal DNS resolver topology. However, real-world applications required us to adapt the design to fit Centric’s Azure Landing Zone environments. One of the conscious decisions for environmental design was to ensure a single connectivity entry point per tenant. Although economically more viable, such a solution makes traffic routing and enforcing separation of different environments – like development, testing, or production more challenging.

However, things got tricky when dealing with Azure Private Endpoint DNS zones. Unlike traditional on-prem DNS setups, Azure has restrictions on creating custom subzones. This meant we couldn’t define multiple private DNS zones for the same resource type within a single compartment, which would cause conflicts. We had to build dedicated DNS transit compartments for each environment to get around this. These compartments have Virtual Networks and connect to a central transit hub responsible for routing traffic between environments.

By separating DNS traffic, we improved security and made it easier to manage DNS queries across different environments. This approach gave us more granular control over who could access and modify the connectivity transit hub, ensuring a higher level of security for this sensitive component.

A Practical Approach to DNS Resolution in Hybrid Cloud

Here’s how the final solution works in practice:

• Central Connectivity Hub: All environments, whether cloud-based or on-premises, connect through a central hub that contains the ExpressRoute circuit or VPN Gateway. Multiple tenants sometimes share the same entry point, making the design more efficient.
• Azure Private DNS Resolvers: These are deployed within dedicated DNS transit compartments. Each compartment includes a Virtual Network with dedicated subnets for the DNS resolver’s inbound and outbound endpoints. These endpoints act as the DNS servers for cloud resources and are linked to on-premises DNS configurations, allowing cloud and on-premises resources to resolve each other’s names seamlessly.
• DNS Forwarding Rules: We’ve implemented DNS forwarding rules for outbound DNS queries (from cloud to on-prem). These rules specify which on-prem DNS zones and servers should handle specific requests, ensuring efficient name resolution across environments.

By linking custom DNS zones to the DNS Resolver’s Virtual Network, we achieved a scalable and efficient framework that directly supports key business goals. Reduced complexity translates into lower IT maintenance costs, faster issue resolution, and greater operational agility – all of which are essential for driving growth and maintaining a competitive edge in the digital economy.

Handling Limitations and Scaling

While Azure provides a highly scalable infrastructure, it’s essential to recognize that even cloud resources have limits. The Azure Private DNS Resolver has a capacity of 10,000 DNS queries per second per endpoint, with up to 5 endpoints available. While this is more than enough for most deployments, large environments—like those running Virtual Desktop Infrastructure (VDI)—may eventually hit this limit.

A centralized DNS resolution model might no longer be viable if that happens. In such cases, we need to implement a decentralized approach, where specific environment DNS zones are resolved locally within each Virtual Network. While this is more complex to manage, it ensures that even the largest environments can maintain efficient DNS resolution without hitting performance bottlenecks.

As environments grow, businesses must continually evaluate the trade-off between centralization and decentralization to align IT strategies with operational priorities. Decentralized DNS resolution may introduce management complexity, but it also provides increased redundancy and can help prevent a single point of failure. In cases where different environments (such as dev, test, and production) have varying demands on DNS queries, distributing the load across multiple Private DNS Resolvers can ensure more balanced and efficient name resolution, especially for high-traffic systems like Virtual Desktop Infrastructure (VDI) or large-scale data platforms. This approach helps safeguard the organization’s reputation and customer trust – critical drivers of long-term growth.

Automating and Enhancing DNS Operations

One of the most powerful tools available in a hybrid environment is automation, which can streamline DNS operations and reduce the risk of human error.

As we scale the infrastructure, Azure policies will play a critical role in ensuring that DNS records are automatically created for every new resource – a storage account, a virtual machine, or a private link. For example, manual DNS registration can be a pain point when deploying a new resource, mainly if something goes wrong during the deployment process. To address this, pre-configured policies in Azure will automatically create DNS records for each resource as it’s deployed. This improves efficiency and ensures that the DNS architecture remains consistent and up-to-date without requiring constant oversight from IT teams.

Monitoring and scaling DNS query capacity will also be critical in the future. As more resources are added to the hybrid environment, the load on DNS infrastructure will increase. By implementing Azure Monitor and Log Analytics, businesses can track DNS query loads in real-time and anticipate when additional Private DNS Resolver endpoints may be necessary. This kind of proactive monitoring will prevent bottlenecks from affecting performance.

Hence, automation in a hybrid cloud environment is not merely a technical uplift but a business enabler. With DNS operations simplified and human errors reduced, organizations can optimize resources better, lower operational expenses, and speed up time-to-market for new services. This accelerates the efficiency of IT and ultimately leads to tangible business results like customer satisfaction and financial performance.

Building a Resilient DNS Framework

In a hybrid cloud environment, building resilience begins with a robust design. Using geo-redundant DNS zones across Azure’s worldwide infrastructure, organizations can protect themselves against regional outages with automatic failover. This approach is particularly important for businesses running mission-critical applications that need 99.99% or higher uptime.

At Centric, we designed our DNS architecture to meet these stringent requirements by incorporating:

• Redundant DNS zones across multiple regions, ensuring seamless failover during outages.
• Load-balancing mechanisms to distribute traffic efficiently, even during high-demand periods.
• Proactive monitoring with Azure Monitor and Log Analytics, allowing for real-time tracking and predictive scaling.
  

The end result is a DNS framework that minimizes downtime, optimizes traffic flow, ensures operational continuity, and provides resilience for business-critical applications. This kind of durable architecture not only bolsters reliability, but also earns the trust of customers and stakeholders through consistent delivery of high-quality digital experiences.

Aligning your DNS strategy with your business initiatives empowers your organization to deliver unmatched agility and reliability in a competitive marketplace.

Bringing it All Together: Lessons Learned and the Road Ahead

This project brought lessons that span far wider than just the technological challenges of managing DNS in a hybrid cloud. They reveal critical business insights that underscore the importance of proactive planning, flexible design, and a strategic approach to IT infrastructure. A robust DNS framework serves not only as a technical backbone but also as a foundation for operational efficiency, security, and scalability – elements vital for business growth.

For organizations navigating hybrid cloud complexities, the key takeaway is clear: a resilient and scalable DNS strategy directly impacts business agility and customer satisfaction. Centric’s success illustrates how early investment in the right design pays off through decreased downtime, improved performance, and decreased operational risks. With business moving in a digital direction and infrastructure becoming increasingly sophisticated, organisations can future-proof their operations and stay ahead of the competition by harnessing Azure’s powerful features to architect their systems with scalability and security in mind.

Final Thoughts: Is Your Hybrid Cloud DNS Strategy Ready for Growth?

A hybrid cloud DNS strategy isn’t merely a technical necessity in a fast-moving business environment like today – it’s a strategic facilitator of growth and innovation. Organizations have to start seeing DNS not as a back-office utility but rather a business asset that enhances operational excellence and customer trust.

To thrive in this landscape, your DNS strategy must deliver on key priorities:

• Resiliency: Ensure uninterrupted operations even in the face of regional outages or traffic surges.
• Scalability: Seamlessly handle growth as your business expands its cloud footprint.
• Security: Safeguard sensitive data and operations with robust, multi-layered protection.

Centric’s DNS architecture for hybrid cloud environments illustrates how the right DNS architecture can turn potential challenges into the innovation opportunities. From powering customer experiences to streamlining internal operations, a customized DNS strategy underpins digital transformation.

Are you ready to align your DNS architecture with your business objectives? Let Centric help you build a future-ready hybrid cloud environment that supports growth, ensures operational stability, and maximizes ROI. Contact us today to learn how we can turn your IT vision into a scalable, resilient reality.