Sidecar Pattern: Architectural Patterns

The Sidecar pattern is a design pattern that focuses on extending the functionality of a primary service by attaching an auxiliary container, known as a “sidecar” to it. This sidecar container runs in the same context as the main service and enhances its capabilities without requiring any modifications to the service code. It provides support functionalities, such as logging, monitoring, service discovery, security, and more.

Sidecar Pattern

As you can see from the above image, we have two sidecar containers, one for log scraping and the other for proxying. Our core container is just responsible for having the core business logic, whereas the proxy service can proxy requests to the core container and the sidecar can scrape logs from the shared file system and push them to the log aggregator!

Advantages of the Sidecar Pattern:

  1. Modularity and Extensibility: With the Sidecar pattern, developers can extend the functionality of a service by attaching or detaching sidecar containers as required. This modular approach allows adding or removing functionalities without affecting the core service, promoting code reuse and enhancing the maintainability of the overall system.
  2. Isolation: The sidecar container runs alongside the main service, ensuring isolation between the core service logic and the auxiliary functionalities. This separation minimizes the impact of failures or issues in the sidecar, allowing independent updates and modifications without impacting the main service.
  3. Scalability: The Sidecar pattern enables scaling individual functionalities independently. By decoupling the core service from the sidecar, you can scale them separately based on their specific demands. For example, if the main/core service requires more processing power, you can scale it without impacting the sidecar and vice versa.

Disadvantages of Sidecar Pattern:

  1. Increased Complexity: Implementing the Sidecar pattern adds an additional layer of complexity to the architecture. It introduces the need for managing and coordinating multiple containers, potentially increasing deployment and operational overhead. Developers must ensure proper communication and synchronization between the main service and the sidecar…
Pratik Pandey -

Senior Engineer with experience in designing and architecting large scale distributed systems.