The sidecar pattern is about co-locating another container in a pod in addition to the main application container. The application container is unaware of the sidecar container and just goes about its business. A great example is a central logging agent. Your main container can just log to stdout, but the sidecar container will send all logs to a central logging service where they will be aggregated with the logs from the entire system. The benefits of using a sidecar container versus adding central logging to the main application container are enormous. First, applications are no longer burdened with central logging, which could be a nuisance. If you want to upgrade or change your central logging policy or switch to a totally new provider, you just need to update the sidecar container and deploy it. None of your application containers change, so you can't break them by accident.