Creating My First Container with correction

Prerequisites #

You must have a machine with Docker installed.

Deployment #

In this section, we will deploy our first Docker container.

1. Find and Download the Image

   We will deploy an Apache web server version 2.4.62. We must find a ready-to-use image and download it.

   You must go to a Docker registry. Since we don't have a private registry yet, we will go to a public one, for example:

   • Docker Hub: https://hub.docker.com/
   • Quay.io: https://quay.io

   
   And select the image that interests us.
   
   

   REMINDER: Depending on the distribution, the Apache server might be called httpd.

   
   So in the case of Docker Hub it gives us:

   docker pull httpd:2.4.62

2. Deploy the Container

   You need to deploy our first container with the following characteristics:
   • Image: apache version 2.4.62
   • Port exposure: 83
   • Container name: my-first-container

   You can create the container with the command below:

   docker run -dit --name my-first-container -p 83:80 httpd:2.4.62

   
   With these explanations:

   • docker run -> command to create a container
   • -dit -> combination of flags that run the container in detached(d), interactive(i) mode and allocate a pseudo-TTY. Be careful, flags evolve with your needs but always go simple first.
   • -p 83:80 -> expose port 83 on the host and 80 on the guest (container)
   • httpd:2.4.62 -> Image used

3. Check Container Status

   You must check that your container is functioning properly. To do this, provide the docker commands for the following actions:
   • Show running containers
   • Show running and stopped containers
   • Show only the my-first-container container
   • Show containers that have the Label AUTHOR:ROUSSELTM

   You can perform the actions with the following commands:

   docker ps

   docker ps -a

   docker ps -a | grep my-first-container

   This command using '|' covers many cases but to do it properly you should use the -f/--filter option. I invite you to read the other parameters (View). So this gives us

   docker ps -f name=my-first-container

   To show containers with labels we cannot use '|' because our ps output does not show labels. We are therefore forced to use filters

   docker ps --filter 'label=AUTHOR=ROUSSELTM'

4. Container Verification

   You must find the command to test the proper functioning of the web server container.

   WARNING: A running container is not necessarily a functioning container. You must check its logs and outputs.

   You can verify with the following command:

   $ curl http://localhost:83 -s

   You should see the text 'It works!' in the output.

Optimization #

In this section, we will optimize our first Docker container.

1. Build a second, lighter container

   As mentioned during the courses, official images must be used in priority, especially the most optimal ones. You must choose another, more size-optimized image.

   You can create a lighter container with Alpine.
   
   

   REMINDER: A good practice is to use Alpine images as soon as they are available.

   
   So in the case of Docker Hub it gives us:

   docker run -dit --name my-second-container -p 84:80 httpd:2.4.62-alpine

2. Compare the disk usage of the two containers

   You must find a command that shows only the two containers with their disk usage, knowing that both image names contain 'my-'

   You can do this with the command below:

   $ docker ps -f name=my- -s
   CONTAINER ID   IMAGE                 COMMAND              CREATED          STATUS          PORTS                NAMES                   SIZE
   410b6a032a0c   httpd:2.4.62-alpine   'httpd-foreground'   19 seconds ago   Up 17 seconds   0.0.0.0:84->80/tcp   my-second-container     2B (virtual 62.9MB)
   0865fe7c9e31   httpd:2.4.62          'httpd-foreground'   3 hours ago      Up 3 hours      0.0.0.0:83->80/tcp   my-first-container      2B (virtual 148MB)

   
   With these explanations:

   • -s -> show disk usage

   You can thus compare the content of the 'SIZE' column.

Difficulty level : ●●○○○ (2/5)