Implementing the Required Degree of Multitenancy Isolation: A Case Study of Cloud-Hosted Bug Tracking System

Implementing the required degree of isolation between tenants is one of the significant challenges for deploying a multitenant application on the cloud. In this paper, we applied COMITRE (COmponent-based approach to Multitenancy Isolation Through request RE-routing) to empirically evaluate the degree of isolation between tenants enabled by three multitenancy patterns (i.e., shared component, tenant-isolated component, and dedicated component) for a cloud-hosted Bug tracking system using Bugzilla. The study revealed among other things that a component deployed based on dedicated component offers the highest degree of isolation (especially for database transactions where support for locking is enabled). Tenant isolation based on performance (e.g., response time) favoured shared component (compared to resource consumption (e.g., CPU and memory) which favoured dedicated component). We also discuss key challenges and recommendations for implementing multitenancy for application components in cloud-hosted bug tracking systems with guarantees for isolation between multiple tenants.