Prometheus permission denied && docker useful tips

According to the Dockerfile of prometheus the USER is set to nobody.

So it makes sense that the above dir is not accessible by the service.

So the problem was solved by performing a

chgrp -R nogroup /prometheus_data

https://stackoverflow.com/questions/54232891/docker-compose-directory-permission-errors-on-bind-mount

nogroup is the group analog to the nobody user. It is used for unprivileged processes so that even if something goes wrong the process does not have the permissions to cause any serious damage to an important user or group.

https://unix.stackexchange.com/questions/22520/what-is-nogroup-groups-purpose

useful tips:
// Multiple email in alertmanager
https://stackoverflow.com/questions/47921028/multiple-email-receivers-in-prometheus-alertmanager-to-field

// For docker-compose.yml is always good to add restart always in the each service so when OS rebooted, this service will automatically restart

services:

  xxx:

    image: xxx/xxx

    networks:

      - back    

    ports:

      - 9091:9091

    restart: always  

You can put comma separated email addresses in the
to field.
// Docker rebuild a running container without building rebuilding dependecies

$docker container stop <container_id> / <service_name>

$docker-compose up -d --no-deps --build <service_name>

#<service_name> is the service name specified in docker-compose.yml file

--no-deps - Don't start linked services.

--build - Build images before starting containers.

https://stackoverflow.com/questions/36884991/how-to-rebuild-docker-container-in-docker-compose-yml

// Docker compose build

docker-compose up -d

//  Docker logs

Don't use "docker logs". Use "docker-compose logs flask" to see the logs of that restarting containers. With your options:

docker-compose logs -f --tail=50 

// Go inside docker container

docker exec -it <mycontainer> bash