docker newbie here. Trying to understand the meaning of the following:
services:
mongo1:
hostname: mongo1
container_name: mongo1
image: mongo:5.0.6
expose:
- 27017
ports:
- 27011:27017
restart: always
Note the ports: 27011:27017 when the docker is up and running I can access the mongo via port 27011, so what is the 27017? and why do I need to expose it:
expose:
- 27017
>Solution :
expose: is a legacy implementation detail of first-generation Docker networking. It does almost nothing in current Docker, and it’s always safe to remove it from Compose files. No other changes are required.
ports: describes how to map a port from the host system to a port in the container. The second port number is a fixed property of the image and is typically the "normal" port the container listens on; in your example MongoDB normally listens on port 27017 and the second port number must be exactly that. The first port number can be any otherwise-unused port on the host system.