running docker containers

you can run docker pull alpine to pull the latest image of alpine linux.

to run the container, you need to use this command.

docker container run -it alpine:latest

-i → interactive mode, with it host terminal commands will not be sent to the container -t → create a tty see here

you can also pass a script while using the run command. the following will run the given command in given container. in our case it prints out the date after every second.

docker container run -it --name looper alpine:latest sh -c "while true; do date; sleep 1; done;"

--rm → passing this flag will delete a container when its exited.

• you can’t run start to restart the container.
• pressing ctrl+c will delete the container.
• to detach from it, press ctrl+p then ctrl+q

exec

you can do the same thing using docker container exec.

docker container exec ID|NAME sh -c "while true; do date; sleep 1; done;"

• exec creates a new process inside your container.
• docker exec -it ID|NAME sh → runs a shell inside your container.

view logs

to view logs, you can use the following command.

docker logs -f ID|NAME

by default, docker will just send the recent logs and exit. if you want to continue receiving logs, use the follow flag (-f).

pause / unpause

docker pause ID|NAME → pause a container docker unpause ID|NAME → unpause a container

attach

you can attach to a container, using docker attach or docker continer attach.

attaching links the stdin and stdout of the host terminal to the container. so if you send sigint (press ctrl+c), then the container will stop. to avoid that you can pass --no-stdin flag or pass --sig-proxy false.

docker attach --no-stdin ID|NAME # does not pass the stdin to container
docker attach --sig-proxy false ID|NAME # does not pass signals like stdint, stdkill, etc.

related

contents

• basic docker commands
• running docker containers
• dockerfile
• bind mount, ports and expose
• docker volumes
• docker-compose
• docker networking

creating container from scratch → https://youtu.be/8fi7uSYlOdc namespaces, cgroups, union filesystems

Link to original

docker multi-platform builds → https://docs.docker.com/build/building/multi-platform/