Docker Commands

Docker Container

A set of layers of images. mostly linux base images, mostly alpine because it is a lightweight version of Linux OS.

Application image is always on top

Docker Architecture

What happens when you run the following commands;

docker pull - connects to docker daemon, check if we have the image or not and then pull the image from the registry, store it on the host

docker run - you specify the parameters and conatiner name, it will connect to docker hostc, chack if we have the image; if yes it creates a conatiner of the image, otherwise it pulls the image from the registry and store the image

Docker Commands

• docker -v: check version and if installed

• docker images - list of images

• docker run - to run a container

• docker run -d - to run a container in detachment mode

• docker run- to see all the logs

• docker run image_name

  You have to pass some environment variables i.e. docker run -e environment_variable image_name

• docker ps - list of running containers

• docker stop container_id - to stop a container

• docker ps -a - to see all running and non-running containers

• docker start container_id - to start an already existing container.

• docker stop container_id - to stop the container

• docker logs conatiner_name - to see all the logs

• docker logs -f container_name - to keep listening to the logs that’ll happen on that container

• docker exec -it objective-keller psql -U postgres - to run some commands inside the container to see what it has, log into the container in an interactive mode

  exec - execute, it - interactive objective-keller - container_name, psql - the mode you want to connect to, -U -specific for postgres, postgres - username

Inside Postgres

• \l - list of all the databases

• create database db_name; - to create db

• \l dt - list tables

• exit - to exit the interactive mode

• docker run —name custom_name -e POSTGRES_PASSWORD=password postgres - to specify the container name.

• docker run -d —name custom_name-detached -e… the versionpostgres - to run in detached mode, gives us a SHA or hashcode

• docker rm container_id - to remove container, you can’t remove a running container

• docker images - to see all the images.

  PS: removing the container doesn’t remove the images

• docker rmi image_id - id or image_name

• docker pull redis : 6.2 - to specify