Docker Compose: depends_on

depends_on

depends_on expresses startup and shutdown dependencies between services.

Short syntax

The short syntax variant only specifies service names of the dependencies. Service dependencies cause the following behaviors:

• Compose creates services in dependency order. In the following example, db and redis are created before web.

• Compose removes services in dependency order. In the following example, web is removed before db and redis.

Simple example:

services:
  web:
    build: .
    depends_on:
      - db
      - redis
  redis:
    image: redis
  db:
    image: postgres

Compose guarantees dependency services have been started before starting a dependent service. Compose waits for dependency services to be "ready" before starting a dependent service.

Copied from: https://docs.docker.com/compose/compose-file/05-services/#depends_on