Gajanan
Day20:Docker Cheetsheet

Day20:Docker Cheetsheet

Gajanan Barure's photo
Gajanan Barure
·

4 min read

Table of contents

Docker Architecture

DevOps architecture consists of five main entities, namely, registry, image, container, daemon, and client.

  • Registry: It hosts public and official images. The Docker registry that we use is Docker Hub.

  • Image: It can be downloaded from the registry directly or implicitly when starting a container.

  • Container: It is basically the instance of an image. Multiple containers can exist for a single image.

  • Docker daemon: A daemon creates, runs, and monitors containers, along with building and storing images.

  • Client: A client talks to Docker daemon via HTTP.

Build

The build command is used for building images from a Docker file. Let’s now check out some of the essential Docker build commands.

Commands

  • To build an image from the Docker file and tag it:
Docker build -t myapp :1.0
  • To list all the images that are locally stored:
Docker images
  • To delete an image from the Docker Store:
Docker rmi alpine: 3.4

Run

The run command is used for creating a container from a specified image. Check out the below-listed run commands.

Commands

  • To create and run a command:
Docker run --name container_name docker_image

Flags used:

  • -d: To detach a container on start

  • -rm: To remove a container once it stops

  • -p: To publish the host IP and the host port to the container port

  • -v: To define and share the volume across containers

  • –read-only: To set to the read-only permission

Ship

Docker gives us the capability of shipping our application container anywhere, on any platform. Let’s check out some commands used for it.

Commands

  • To pull an image from the registry:
Docker pull alpine:3.4
  • To retag a local image with a new image name:
Docker tag alpine:3.4 myrepo/ myalpine:3.4
  • To log in to the registry:
Docker login my.registry.com:8000
  • To push an image to the registry:
Docker push myrepo/ myalpine:3.4

Clean up

To prevent wasting resources, we must know how to clean up. In this Docker cheat sheet tutorial, next, a few essential clean-up commands are provided.

Commands

  • To clean an unused/dangling image:
Docker image prune
  • To remove an image that is not used in a container:
Docker image prune -a
  • To prune the entire system:
Docker system prune
  • To leave a swarm:
Docker swarm leave
  • To remove a swarm:
Docker stack rm stack_name
  • To kill all running containers:
Docker kill $ (docker ps -q)
  • To delete all stopped containers:
docker rm $(docker ps -a -q)
  • To delete all images:
docker rmi $(docker images -q)

Services

Commands

To list all services running in a swarm:

Docker service ls

To see all running services:

Docker stack services stack_name

To see all service logs:

Docker service logs stack_name service_names

To scale a service across qualified nodes:

Docker service scale stack_name_service_name= replicas

Interact with container Commands

To run a command in a container:

Docker exe -ti container_name command.sh

To follow container logs:

Docker logs -ft container name

To save a running container as an image:

Docker commit -m “commit message” -a “author” container_name username/image_name: tag

Important Terms

Some of the important terms to know about while using Docker container are listed below:

  • Layer: Read-only files to provision the system

  • Image: Read-only layer that is the base of an image

  • Container: A runnable instance of the image

  • Registry/hub: A central place where images reside

  • Docker machine: A VM to run the Docker container

  • Docker Compose: A VM to run multiple containers as a system

Docker Volumes:

  • docker volume create <name>: create a new Docker volume

  • docker volume ls: list all Docker volumes on your system

  • docker volume inspect <name>: inspect the details of a Docker volume

  • docker run -v <name>:<path>: attach a Docker volume to a container

  • docker run -v <host-path>:<container-path>: mount a host directory as a Docker volume

Docker compose Commands:

docker-compose start
docker-compose stop

docker-compose pause
docker-compose unpause

docker-compose ps
docker-compose up
docker-compose down

Thank you for reading!! Hope you find this helpful.

#day20challenge#90daysofdevops

Always open for suggestions..!!

Thankyou Shubham Londhe !!

Devops