Sidecar Pattern vs DaemonSet.

A Sidecar runs alongside an application container in the same Pod. A DaemonSet runs exactly one Pod on every Node in the cluster.

Use a Sidecar when the helper process is tightly coupled to a specific application instance (e.g., an Envoy proxy encrypting traffic for that specific app). Use a DaemonSet when the helper process needs to monitor or collect data for the entire physical Node (e.g., Fluentd collecting logs from the docker daemon).