Essential Docker Commands

Docker has become an integral part of modern DevOps practices, offering a robust platform for containerizing applications, ensuring consistency across different environments, and simplifying deployment processes. If you're new to Docker or looking to brush up on your skills, here's a guide to the essential Docker commands you should know when working on a Virtual Private Server (VPS).

Running Containers

docker run

This command creates and starts a new container from an image.

docker run -it --name mycontainer image:name

-i: Keeps STDIN open even if not attached.

-t: Allocates a pseudo-TTY.

--name: Names your container for easier management.

For a detached container (running in the background):

docker run -d --name mycontainer image:name

Managing Containers

docker ps

Lists running containers. Add -a to see all containers, including stopped ones.

docker ps
docker ps -a

docker exec

Executes a command inside a running container. Useful for debugging or getting a shell inside a container:

docker exec -it mycontainer bash

docker logs

Views logs from a container:

docker logs mycontainer

docker stop

Stops a running container:

docker stop mycontainer

docker rm

Removes a container (must be stopped first):

docker rm mycontainer

Managing Images

docker build

Builds an image from a Dockerfile:

docker build -t myimage:v1 .

-t: Tags the image with a name and optionally a tag.

docker images

Lists all images on your system:

docker images

docker rmi

Removes one or more images:

docker rmi image:name

docker pull

Pulls an image from a registry (default is Docker Hub):

docker pull image:name

Additional Useful Commands

docker start: Starts a stopped container.

docker restart: Restarts a running container.

docker commit: Creates a new image from a container's changes.

docker push: Pushes an image to a Docker registry.

Advanced Use

For managing applications composed of multiple containers, docker-compose is invaluable. It allows you to define and run multi-container Docker applications with a single configuration file.

Conclusion These commands form the backbone of Docker usage for DevOps on a VPS. Mastering them will give you the flexibility to manage containers efficiently, whether you're deploying new applications or maintaining existing ones. Remember, Docker's strength lies in its ability to create consistent environments across different stages of development and deployment, making these commands not just useful but essential for any DevOps toolkit.