The d in dockerd , and the d in containerd — Daemon

A daemon is a background process that isn't controlled by humans through a GUI, similar to a system center. In the 01 world, many daemons are identified by adding the letter "d" as a suffix to their names.

For example:

• dockerd is for managing containers (higher level), handling cli requests, interacting with container runtime, etc.

• In the k8s eco, the CRI-compliant tool containerd also has a "d"; it's part of the container runtime, responsible for managing the container lifecycle (lower level).

  Kubernetes just sets up the ground rules(specification APIs like CRI, CNI, CSI) and lets experts build their stuff. When they make something that works, the K8s team can officially approve it.

• I used to wonder why httpd had a "d" at the end haha. It's Apache's.

systemd is the largest daemon, functioning as Linux's main background system. systemd can manage other daemons, while daemons communicate with each other through IPC (such as unix socket or http/gRPC).

dockerd → gRPC → containerd

https://nanikgolang.netlify.app/post/containers/