Why orchestration matters in Docker - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a Docker container named 'webapp'.

Docker

docker run --name [1] -d nginx

Drag options to blanks, or click blank then click option'

Abackend

Bdatabase

Ccache

Dwebapp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong container name that does not match the app.

The --name option sets the container's name. Here, 'webapp' is the correct name to start the container.

2fill in blank

medium

Complete the command to list all running Docker containers.

Docker

docker [1]

Drag options to blanks, or click blank then click option'

Aps

Bimages

Crun

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'docker images' which lists images, not containers.

The docker ps command lists all running containers.

3fill in blank

hard

Fix the error in the Docker Compose file to define a service named 'app'.

Docker

services:
  [1]:
    image: nginx
    ports:
      - "80:80"

Drag options to blanks, or click blank then click option'

Abackend

Bcache

Capp

Ddatabase

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong service name that does not match the app.

The service name should be 'app' as required. This identifies the container in orchestration.

4fill in blank

hard

Fill both blanks to create a Docker Compose service that restarts automatically on failure.

Docker

services:
  web:
    image: nginx
    restart: [1]
    ports:
      - "[2]:80"

Drag options to blanks, or click blank then click option'

Aon-failure

Balways

C8080

D80

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'always' restart policy when only 'on-failure' is requested.

Swapping port numbers incorrectly.

The restart: on-failure option restarts the container only if it fails. Port mapping 8080:80 exposes port 80 inside the container to port 8080 on the host.

5fill in blank

hard

Fill all three blanks to define a Docker Compose service with environment variables and volume mapping.

Docker

services:
  db:
    image: postgres
    environment:
      - POSTGRES_USER=[1]
      - POSTGRES_PASSWORD=[2]
    volumes:
      - [3]:/var/lib/postgresql/data

Drag options to blanks, or click blank then click option'

Aadmin

Bsecret123

C./dbdata

D/data

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect environment variable names.

Swapping volume paths.

Environment variables set the database user and password. Volume mapping ./dbdata:/var/lib/postgresql/data stores data on the host for persistence.