inception

This README would normally document whatever steps are necessary to get your application up and running.

questions

? what means mounted in "a file or directory on the host machine is mounted into a container" ?
? why the volumes cannot be modify outside docker ?

sudo netstat -tulpn to print network connections and see if nginx is running
or : ps -ax | grep nginx
sudo nginx -s quit to stop it
sudo docker system prune -af --volumes -> -a also unused images, -f without prompt for confirmation
- remove stopped containers
- remove unused networks
- remove unused images
- remove build cache
sudo docker ps -q all runnings containers
sudo docker stop $(sudo docker ps -q) stop all runnings containers

nginx by default will create some child process (a master and some workers), then it quits (doc ?)
when the first process of a docker container exit, the container exit (doc ?)
so we must tell nginx to not go background : "-g 'daemon off'"
pid1 docker problem
official nginx docker image
"If you add a custom CMD in the Dockerfile, be sure to include -g daemon off; in the CMD in order for nginx to stay in the foreground, so that Docker can track the process properly (otherwise your container will stop immediately after starting)!"
SO discussion on "-g 'daemon off'"
"When PID 1 exits, the container will exit" (where is says in the doc ?)
"By design, containers started in detached mode exit when the root process used to run the container exits"

remove old versions

sudo apt remove docker docker-engine docker.io containerd runc preparing directory
sudo apt update
sudo apt install ca-certificates curl gnupg lsb-release
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null installing docker engine
sudo apt update
sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin check if installation worked
sudo docker run hello-world installing docker compose checked version on github release, see above
notice the 'v' below, before the version name (docker doc has it wong)
sudo curl -L "https://github.com/docker/compose/releases/download/v2.10.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose build and run a docker image
be in directory with a Dockerfile
sudo docker build --tag <name> .
sudo docker run <name>
sudo docker images to list docker images
sudo docker image rm <number>
sudo docker ps to list docker processes
sudo docker ps rm <name> execute a docker-compose file
be in directory with a docker-compose.yml file
sudo docker-compose up

bind mounts are normal files anywhere on the computer, that docker container can access with absolut path and modify. They can also be modified without docker, since they are juste files
volumes are only modifiable by docker, they don't need an absolut path, and they are not dependent of host architecture