Verifying installation with docker run hello-world - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to run the Docker hello-world image.

Docker

docker [1] hello-world

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

Apull

Brun

Cpush

Dbuild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'docker build' instead of 'docker run'.

Using 'docker pull' which only downloads the image but does not run it.

The docker run command starts a container from an image. Here, it runs the hello-world image to verify Docker is installed correctly.

2fill in blank

medium

Complete the command to pull the hello-world image explicitly before running it.

Docker

docker [1] hello-world

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

Apull

Brun

Cstart

Dexec

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'docker run' when the task asks to pull the image only.

Using 'docker exec' which runs commands inside a running container.

The docker pull command downloads the image from Docker Hub without running it. This is useful to get the image first.

3fill in blank

hard

Fix the error in the command to run the hello-world image.

Docker

docker [1] hello-world

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

Aruns

Bstart

Crunning

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Typing 'runs' instead of 'run'.

Using 'start' which is for starting stopped containers, not running new ones.

The correct command is docker run. Using 'runs' or 'running' is invalid syntax and causes an error.

4fill in blank

hard

Fill both blanks to complete the command that runs the hello-world image and removes the container after it exits.

Docker

docker [1] --rm [2]

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

Arun

Bhello-world

Cstart

Dcontainer

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' instead of 'run'.

Using 'container' instead of the image name.

The docker run --rm hello-world command runs the image and removes the container automatically after it finishes.

5fill in blank

hard

Fill all three blanks to run the hello-world image in detached mode with a custom name.

Docker

docker [1] -d --name [2] [3]

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

Arun

Bmy-hello

Chello-world

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' instead of 'run'.

Mixing up the container name and image name.

This command runs the hello-world image in detached mode (-d) and names the container my-hello.

Practice

1. What does the command docker run hello-world do?

easy

A. It lists all running Docker containers.

B. It updates Docker to the latest version.

C. It removes all Docker containers from the system.

D. It downloads and runs a test container to verify Docker installation.

Solution

1. Step 1: Understand the command purpose

   The command docker run hello-world pulls a small test image from Docker Hub if not present and runs it.

2. Step 2: Observe the output

   The container prints a confirmation message indicating Docker is installed and working correctly.

3. Final Answer:

   It downloads and runs a test container to verify Docker installation. -> Option D

4. Quick Check:

   docker run hello-world = verify Docker installation [OK]

Hint: Remember: hello-world test confirms Docker works [OK]

Common Mistakes:

• Thinking it updates Docker
• Confusing it with container removal
• Assuming it lists containers

2. Which of the following is the correct syntax to run the hello-world Docker container?

easy

A. docker run hello-world

B. docker start hello-world

C. docker execute hello-world

D. docker build hello-world

Solution

1. Step 1: Identify the command to run a container

   The correct command to run a container is docker run followed by the image name.

2. Step 2: Match the image name

   The image name here is hello-world, so the full command is docker run hello-world.

3. Final Answer:

   docker run hello-world -> Option A

4. Quick Check:

   docker run + image name = docker run hello-world [OK]

Hint: Use 'docker run' to start containers, not 'start' or 'build' [OK]

Common Mistakes:

• Using 'docker start' which only starts stopped containers
• Using 'docker execute' which is invalid
• Using 'docker build' which builds images, not runs them

3. What output should you expect after successfully running docker run hello-world?

medium

A. No output, just a blank screen.

B. A message confirming Docker is installed and working.

C. A list of all Docker images on your system.

D. An error saying 'image not found'.

Solution

1. Step 1: Understand the purpose of the hello-world container

   This container prints a friendly message confirming Docker installation.

2. Step 2: Recognize expected output

   The output includes a welcome message and instructions confirming Docker works.

3. Final Answer:

   A message confirming Docker is installed and working. -> Option B

4. Quick Check:

   hello-world output = confirmation message [OK]

Hint: Look for confirmation text after running hello-world [OK]

Common Mistakes:

• Expecting image list instead of message
• Confusing error output with success
• Thinking no output means success

4. You run docker run hello-world but get an error: Cannot connect to the Docker daemon. What is the likely cause?

medium

A. Docker daemon is not running on your system.

B. The hello-world image does not exist.

C. You typed the command incorrectly.

D. Your internet connection is down.

Solution

1. Step 1: Analyze the error message

   The error 'Cannot connect to the Docker daemon' means the Docker service is not running or accessible.

2. Step 2: Understand Docker daemon role

   The Docker daemon manages containers; if it is stopped, commands cannot run.

3. Final Answer:

   Docker daemon is not running on your system. -> Option A

4. Quick Check:

   Docker daemon stopped = connection error [OK]

Hint: Check if Docker service is running before running containers [OK]

Common Mistakes:

• Assuming image missing causes daemon error
• Blaming command syntax without checking daemon
• Ignoring daemon status and blaming internet

5. After installing Docker, you run docker run hello-world but see a permission denied error. What should you do to fix this?

hard

A. Delete all Docker images and try again.

B. Reinstall Docker completely.

C. Run the command with elevated permissions, e.g., using sudo.

D. Restart your computer without changing anything.

Solution

1. Step 1: Understand permission denied error

   This error often means your user lacks rights to access Docker daemon.

2. Step 2: Use elevated permissions

   Running sudo docker run hello-world grants necessary rights to run the container.

3. Final Answer:

   Run the command with elevated permissions, e.g., using sudo. -> Option C

4. Quick Check:

   Permission denied fix = use sudo [OK]

Hint: Use sudo if permission denied running Docker commands [OK]

Common Mistakes:

• Reinstalling Docker unnecessarily
• Deleting images instead of fixing permissions
• Restarting without addressing permissions