Custom Health-Checks for a Hybrid Cloud Application

In an active-passive dual-region architecture on Microsoft Azure, key services like Application Service Environment (ASE), Azure App Services, Azure Traffic Manager, and Azure Application Gateway can ensure resilience.

However, what if you introduce on-prem infrastructure for a hybrid cloud environment? This means that we are also introducing ExpressRoute connecting to an on-prem data center. Some critical applications are not migrated fully to a cloud environment and operate from both. This is where it becomes complicated to ensure high availability. A solution presents itself in creating a simple custom healthcheck page to check health of each downstream endpoint, including ExpressRoute. Then, point the Traffic Manager’s healthcheck probe against this website, which can be deployed onto an App Service, or a different compute resource such as Azure Functions. This custom healthcheck page should return an appropriate HTTP response based on its internal logic checks (whether a downstream endpoint, ExpressRoute, or a combination thereof is up or down). This can then be used as a trigger for Traffic Manager to fail over to the passive region if any downstream services within the primary Azure region or if ExpressRoute itself are down.

Regular health-checks are crucial for maintaining continuous availability and optimal performance.

Conducting health-checks helps identify and address issues proactively, minimizing downtime and ensuring a resilient infrastructure. This is essential for business continuity, emphasizing the importance of a robust and reliable cloud setup.