Fredy Larson

Fredy Larson

1616392928

Docker File vs Docker Compose: What's the Difference?

Confused between Dockerfile and docker-compose because they look and sound similar? But they are not. Read this to clear your doubts.

I’ve seen many people get confused between a Dockerfile and a Compose file. This is primarily because both are used to modify a Docker image in a way, though it’s not technically correct.

It is easy to confuse the two terms, but it’s also necessary to understand the difference when making a conversation with a colleague or your (potential) employer.

Dockerfile is what’s used to create a container image, and a Compose file is what’s used to deploy an instance of that image as a container.

Let me go in a bit of detail so that you properly understand the difference between Docker Compose and Dockerfile.

#docker

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Buddha Community

Docker File vs Docker Compose: What's the Difference?
Iliana Welch

Iliana Welch

1595249460

Docker Explained: Docker Architecture | Docker Registries

Following the second video about Docker basics, in this video, I explain Docker architecture and explain the different building blocks of the docker engine; docker client, API, Docker Daemon. I also explain what a docker registry is and I finish the video with a demo explaining and illustrating how to use Docker hub

In this video lesson you will learn:

  • What is Docker Host
  • What is Docker Engine
  • Learn about Docker Architecture
  • Learn about Docker client and Docker Daemon
  • Docker Hub and Registries
  • Simple demo to understand using images from registries

#docker #docker hub #docker host #docker engine #docker architecture #api

Roosevelt Hettinger

Roosevelt Hettinger

1596691740

Docker manifest - A peek into image's manifest.json files

docker manifest – An experimental feature !

The image manifest provides a configuration and a set of layers for a container image.

This is an experimental feature. To enable this feature in the Docker CLI, one can edit the config.json file found in ~/.docker/config.json like :

{
        "auths": {
                "https://index.docker.io/v1/": {
                        "auth": "XXXXXXX"
                }
        },
        "HttpHeaders": {
                "User-Agent": "Docker-Client/19.03.8 (linux)"
        },
        "experimental": "enabled",
        "debug": true
}

What is ‘docker manifest’ ?

The docker manifest command does not work independently to perform any action. In order to work with the docker manifest or manifest list, we use sub-commands along with it. This manifest sub-command can enable us to interact with the image manifests. Furthermore, it also gives information about the OS and the architecture, that a particular image was built for.

A single manifest comprises of information about an image, it’s size, the layers and digest.

A manifest list is a list of image layers (manifests) that are, created by specifying one or more image names. It can then be used in the same way as an image name in docker pull and docker run commands.

Commands to get started with :

After enabling this feature, one would be able to access the following command :

docker-manifest-enter image description here

These commands are easy to use. It basically avoids the need for pulling and running and then testing the images locally, from a docker registry.

Next, to inspect an image manifest, follow this syntax,

 docker manifest inspect image-name

enter image description here

.

#devops #docker #devops #docker #docker learning #docker-image

August Murray

August Murray

1615008840

Top 24 Docker Commands Explained with Examples

In my previous blog post, I have explained in detail how you can Install Docker and Docker-compose on Ubuntu

In this guide, I have explained the Top 24 Docker Commands with examples.

Make sure you have sudo or root privileges to the system.

Docker Commands

  1. The command to check the version of Docker installed.
  2. To look/search for available docker images from the Docker registry.
  3. To pull docker images from the Docker registry.
  4. Listing all the docker images
  5. Creating / Running docker container from Docker image.
  6. To list the actively running docker containers.
  7. To list all the docker containers
  8. To stop a Container
  9. To start a Container
  10. To restart a Docker container
  11. To login to running Docker container
  12. To delete the stopped Docker containers
  13. To delete Docker images from the Local system
  14. To check logs of a running Docker container
  15. Killing docker containers
  16. Log in to Docker Hub registry (hub.docker.com)
  17. Removing docker hub registry login from the system.
  18. Check active resource usage by each containers
  19. Rename a Docker container
  20. To display system wide information of Docker
  21. Inspecting a Docker container
  22. Building docker images from Docker file
  23. Creating new docker images from a Container
  24. Pushing Docker images from Local to Docker registry.

#docker #docker-command #containers #docker-compose #docker-image

Loma Baumbach

Loma Baumbach

1600358785

Deploy a Tomcat Application Using Docker-Compose

In this blog, we will learn what is docker-compose and how we can deploy a tomcat application which uses mysql database. We will learn how we can setup a development environment using docker-compose in a single command

Prerequisite:

  1. Docker and Docker-compose installed

INTRODUCTION

  • Docker-compose is a tool which is used to deploy multi-container application.
  • One single yaml file to deploy your application on the server.
  • Best suited for the developers to setup their workstation in a single command without installing any kind of dependencies for the application
  • docker-compose up to start your application
  • docker-compose down to clean up all the docker containers

Let’s take an example here:

We have a project called user registration which uses mysql for storing the data . In terms of microservices, we can say that we have two services as shown below:

  • Web Service
  • Database Service

You can clone this git repo and try the below example

Explanation of docker-compose

  1. **version : **This is the version as per the docker engine you have installed on your machine
  2. **services: **This is the main tag which is used to configure multiple services and under that we have details of all the services

3. web: This is our service name -> using image, ports and volumes

4. **volumes: **To store the database files

Now we will create main docker-compose file which will together launch a tomcat, mysql and phpmyadmin container

Tomcat container — To run your application

**Database container **— To store the data

PhpMyAdmin — Access the database through GUI

So we will have three services

  1. db — we are using local path to store the data so that when you run docker-compose down all your data will retain. If you use the volume then all data will get lost if you run the docker-compose down

Also, we are importing sql file so that our database is ready with the sample data. It is good so that each developer will always have the base or the actual data to run their application on the local machine

2. phpmyadmin — which is used to access the database through GUI and it depends on service db

3. web — which is used to access your web application and it also depends on service db

version: '3.3'
services:
   db:
     image: mysql:5.7
     volumes:
       - /opt/test:/var/lib/mysql
       - ./mysql-dump:/docker-entrypoint-initdb.d
     environment:
       MYSQL_ROOT_PASSWORD: root
       MYSQL_DATABASE: testdb1
       MYSQL_USER: testuser
       MYSQL_PASSWORD: root
     ports:
       - 3306:3306
phpmyadmin:
    depends_on:
      - db
    image: phpmyadmin/phpmyadmin
    ports:
      - '8081:80'
    environment:
      PMA_HOST: db
      MYSQL_ROOT_PASSWORD: root
web:
    depends_on:
      - db
    image: tomcat
    volumes:
      - ./target/LoginWebApp-1.war:/usr/local/tomcat/webapps/LoginWebApp-1.war
    ports:
      - '8082:8080'
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: testdb1
      MYSQL_USER: testuser
      MYSQL_PASSWORD: root

#docker-compose #docker-image #docker

Hudson Kunde

Hudson Kunde

1596340980

How to Install and Use Docker Compose on Debian 9

Docker Compose is a tool that allows you to define and orchestrate multi-container Docker applications. It uses a YAML file to configure the application’s containers, networks, and volumes.

Compose can be used for various purposes. Single host application deployments, automated testing, and local development are the most popular use cases for Docker Compose.

This tutorial will walk through the process of installing the latest version of Docker Compose on Debian 9. We’ll also explore the basic Docker Compose concepts and commands.

Prerequisites

Ensure that you have met the following prerequisites before continuing with this tutorial:

  • Logged in as a user with sudo privileges .
  • Have Docker installed on your Debian 9 machine.

Install Docker Compose on Debian

The Docker Compose installation package is available in the official Debian 9 repositories but it may not always be the latest version. The recommended approach is to install Docker Compose from the Docker’s GitHub repository.

At the time of writing this article, the latest stable version of Docker Compose is version 1.23.1. Before downloading the Compose binary visit the Compose repository release page on GitHub and check if there is a new version available for download.

  1. Perform the following steps to install the latest version of Docker Compose on Debian 9:Start by downloading the Docker Compose binary into the /usr/local/bin directory using the following [curl](https://linuxize.com/post/curl-command-examples/) command:
sudo curl -L "https://github.com/docker/compose/releases/download/1.23.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
  1. When the download is complete, give executable permissions to the Compose binary:
sudo chmod +x /usr/local/bin/docker-compose
  1. Verify the installation by typing:
docker-compose --version
  1. The output will look something like this:
docker-compose version 1.23.1, build b02f1306

Getting started with Docker Compose

In this section we will show how to use Docker Compose to manage a WordPress stack on your Debian 9 machine.

#docker #debian 9 #docker compose #yaml file #volumes #networks