||Lightweight, executable snapshop of an application to run. Holds code, env, libs, runtime, config files, etc.
||Executed, running image. Runs completely isolated from host environment.
||One Docker Kernel per host. It's a layer between containers and Host OS, that allows containers to run natively.
||A service runs multiple replicas of a container. Handles load balancing, sclaing, etc, in prod. In that contaxt, a container is called a
||It's a swarm. Manages multiple services and how they interact between each other. Docker-managed SoA in a way.
| Swarm Group
||Group of machines (physical or virtual) -called nodes- running multiple apps in a cluster.
Swarm Manager is 1 machine controlling the others (send commands etc).