如何将 mosquitto docker 日志挂载到本地 PC

Question

I have installed eclipse-mosquitto docker image in Ubuntu. I am trying to run it using docker-compose . Mosquitto needs 3 directories as explained in docker hub page:

1. config : which contains mosquitto.conf and bridge.conf files
2. data: which contains mosquitto.db file
3. log: which contains mosquitto.log file

In my local PC I have created a directory named mosquitto which has all the above directory and files:

mosquitto

    -> config
        -> mosquitto.conf
        -> conf.d
            -> bridge.conf 
    -> data
        -> mosquitto.db
    -> log
        -> mosquitto.log

Below is the docker-compose.yml file:

version: '2.4'

services:
    mosquitto:
        image: eclipse-mosquitto:latest
        volumes:
            - /home/john/Documents/docker/mosquitto:/mosquitto
        restart: always

and I am starting it as sudo docker-compose up . Its container starts to run fine and I can see all the directories and files properly mounted inside the mosquitto container. I can see the logs starts to come and mosquitto.log file size is also increasing inside the container but there is no log present in my local pc.

Why is this happening when I have mounted the volume. I want to also get the logs in the mosquitto.log in ubuntu local pc. How can I do this. Can anyone please suggest some good solution. Thanks

Answer 1

This is because docker is creating 2 local volumes and mounting them on top of the /mosquitto directory to hold the persistence and log data.

Add the extra mounts to the volumes section and it will then bind the local directories rather than create unnamed local volumes.

version: '2.4'

services:
    mosquitto:
        image: eclipse-mosquitto:latest
        volumes:
            - /home/john/Documents/docker/mosquitto:/mosquitto
            - /home/john/Documents/docker/mosquitto/data:/mosquitto/data
            - /home/john/Documents/docker/mosquitto/log:/mosquitto/log
        restart: always