What is the Sidecar pattern and what is it used for?

The Sidecar pattern is an architectural approach where an additional component (sidecar) runs alongside the main application in the same environment (for example, in the same container or Kubernetes pod). This component extends or complements the functionality of the main service without directly modifying it.

Main goals of using Sidecar:

• Isolation of auxiliary functions (logging, monitoring, proxy, configuration).
• Ensuring independent scaling and updating of auxiliary services.
• Simplifying maintenance and reusability of code.

Example: in a microservices architecture, a sidecar can perform functions of a service mesh, providing routing and security for traffic without changing the main application.