TOP : version service network volumes config secrets
service : build deploy
Each service MAY also include a Build section, which defines how to create the Docker image for the service. Compose implementations MAY support building docker images using this service definition. If not implemented the Build section SHOULD be ignored and the Compose file MUST still be considered valid.
Build support is an OPTIONAL aspect of the Compose specification, and is described in detail here
Each Service defines runtime constraints and requirements to run its containers. The deploy section groups these constraints and allows the platform to adjust the deployment strategy to best match containers’ needs with available resources.