When you use a docker-compose,you can want restart a service without restart all services.
Type the following command :
docker-compose up --no-deps containername
When you use a docker container, it could be interresting to be with root user.
It can be necessary to install some temporary tools for instance.
To simply you connect to the container with root user (id = 0), type the following command :
docker exec -u 0 -it mycontainer /bin/sh