What's so bad about sidecars, anyway?
Sidecars are a design pattern in which an auxiliary container is deployed alongside the main containers, extending the capabilities of individual deployments to pursue a specific task or function.
In this article, you'll explore the benefits and limitations of using sidecars and the specific use cases where they are most appropriate. You’ll learn how to determine whether a sidecar is a suitable choice for a particular scenario as well as how to implement sidecars to maximize their benefits.
Sidecars are used to extend the functionality of a primary container as an add-on or side container to the primary one. In orchestration systems like Kubernetes, a pod is the smallest deployable unit and can contain multiple containers. The most common practice is to have a single primary container and one or more sidecar containers in a pod, if you decide to use them.
The primary container is responsible for the main functionality of the pod, while sidecar containers provide auxiliary or complementary functions. The primary benefit of using sidecars is that they allow developers to add additional functionality to an existing service without having to modify the code of that service, making it possible for each to be updated and managed separately.
