Building ClickHouse Cloud on Microsoft Azure

ClickHouse has announced the General Availability of ClickHouse Cloud on Azure. The architecture of ClickHouse Cloud is designed to be as cloud service provider (CSP) neutral as possible, allowing it to be reused across different CSPs such as AWS, GCP, and Azure. The Control Plane is built in AWS and interacts with the Data Plane in AWS, GCP, and Azure. ClickHouse Cloud's components are best described as two different and independent logical units: the Control Plane (the user-facing layer) and the Data Plane (the infrastructure-facing part). The architecture is designed to be CSP agnostic, but each individual CSP has its own quirks and differences. One challenge faced in adapting the architecture to Azure was the way cloud resources are organized. To address this issue, a solution was designed where a pool of Azure subscriptions for customer ClickHouse clusters is created, and whenever a new instance is created by a customer, it is randomly assigned to a subscription picked from the pool. This design works around the resource limit issue mentioned earlier. The next section will explain how they addressed these problems using cellular architecture.