Which module offers a multi-tenant cloud messaging service in OpenStack?

Zaqar is the module in OpenStack that provides a multi-tenant cloud messaging service. This service supports both messaging and queuing functionalities, allowing for the delivery of messages between different services or components in a cloud environment. It is designed to facilitate scalable and reliable messaging operations, which is essential for decoupling services within a cloud architecture.

Zaqar offers capabilities such as message persistence, scalability, and support for different messaging patterns, making it suitable for applications that require inter-service communication. The multi-tenant aspect enables multiple users or tenants to utilize the messaging service securely while keeping their data isolated from each other.

This is particularly important in cloud environments where different organizations might share the same infrastructure but require strict separation of their workloads and data. The features of Zaqar make it well-suited for modern, microservices-based applications that depend on efficient message queuing and push notifications.

In contrast, the other modules – Barbican, Murano, and Magnum – serve different purposes; Barbican is focused on key management and security, Murano provides application deployment, and Magnum manages container orchestration, which do not directly relate to messaging services.