Skip to main content

OpenStack Zaqar

OpenStack Zaqar is a multi-tenant cloud messaging service (messaging middleware) that provides scalable message queuing and notification APIs for applications running on OpenStack-based or integrated infrastructure.

  • Multi-tenant message queuing and notification service (messaging middleware) for cloud applications
  • Support for both queue-based messaging and publish-subscribe notifications via Hypertext Transfer Protocol (HTTP) APIs (application integration)
  • Designed to integrate with other OpenStack services through Keystone authentication and OpenStack-native APIs (cloud platform integration)
  • Provides asynchronous communication between distributed components and services (distributed systems messaging)
  • Supports pluggable backends for message storage and transport, enabling deployment flexibility (infrastructure extensibility)

More About OpenStack Zaqar

OpenStack Zaqar is the messaging service component within the OpenStack ecosystem, focused on providing multi-tenant, web-accessible message queuing and notification capabilities (messaging middleware) for cloud applications. It addresses the need for asynchronous communication between distributed services, enabling decoupled architectures where producers and consumers of messages do not require direct or synchronous interaction.

Zaqar exposes its functionality through RESTful HTTP APIs (application integration), allowing applications to publish, store, and consume messages via queues or to use subscription-based notification patterns. The service is designed for multi-tenancy, aligning with OpenStack’s project and tenant model, and it integrates with OpenStack Keystone (identity and access management) for authentication and authorization. This model allows operators to provide messaging as a shared service within private, public, or hybrid OpenStack clouds.

Core capabilities include support for queue creation and management, posting and retrieving messages, message claiming and time-to-live controls, and subscription mechanisms for notifications (distributed systems messaging). These features support patterns such as work queues, task distribution, and event-driven processing. Zaqar’s Application Programming Interface (API) design allows language-agnostic access, so any client capable of making HTTP requests can interact with the service, and client libraries exist for common programming environments.

Zaqar uses a pluggable backend architecture (infrastructure extensibility), enabling operators to deploy it with different storage and transport engines depending on scalability, performance, and operational requirements. This approach allows adaptation to various infrastructure choices while preserving a consistent API surface for applications. The service is intended to operate alongside other OpenStack services such as Nova (compute), Neutron (networking), and Cinder (block storage), providing a messaging layer that application workloads can use without leaving the OpenStack environment.

In enterprise and institutional environments, Zaqar is used to coordinate microservices, batch jobs, and event-driven workflows (cloud application architecture). It supports scenarios such as buffering requests, load leveling between front-end and back-end components, and distributing tasks to worker pools. Because it is an OpenStack-native component, Zaqar fits into existing OpenStack-based automation, monitoring, and quota models, and can be managed using familiar OpenStack operational practices.

Within a technical directory, OpenStack Zaqar is categorized as a cloud messaging and notification service (messaging middleware) within the broader OpenStack cloud infrastructure stack. It serves as a building block for distributed application design in OpenStack environments, providing standardized messaging APIs that align with OpenStack’s identity, multi-tenancy, and service catalog frameworks.