Starting and stopping containers in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to start a Docker container named myapp.

Docker

docker container [1] myapp

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

Astart

Bstop

Cremove

Dpause

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'stop' instead of 'start' will stop the container instead of starting it.

Using 'remove' deletes the container, not starts it.

The start command is used to start a stopped Docker container.

2fill in blank

medium

Complete the command to stop a running Docker container named webserver.

Docker

docker container [1] webserver

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

Arestart

Bexec

Cstop

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'restart' will stop and then start the container again.

Using 'exec' runs a command inside the container but does not stop it.

The stop command stops a running container gracefully.

3fill in blank

hard

Fix the error in the command to start a container with the name 'db'.

Docker

docker container [1] db

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

Astart

Brun

Ccreate

Dbuild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'run' tries to create a new container instead of starting an existing one.

Using 'create' only creates a container but does not start it.

The start command is used to start an existing container named 'db'. The run command creates and starts a new container, which is different.

4fill in blank

hard

Fill both blanks to stop and then remove a container named testapp.

Docker

docker container [1] testapp && docker container [2] testapp

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

Astop

Bstart

Crm

Dpause

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to remove a running container without stopping it first causes an error.

Using 'start' instead of 'stop' will not stop the container.

First, you stop the container with stop, then remove it with rm.

5fill in blank

hard

Fill all three blanks to start a container named app1, then stop it, and finally remove it.

Docker

docker container [1] app1 && docker container [2] app1 && docker container [3] app1

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

Arestart

Bstop

Crm

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'restart' instead of 'start' at the beginning.

Trying to remove the container before stopping it.

You start the container with start, stop it with stop, and remove it with rm.

Practice

1. Which command is used to start a container that has been stopped in Docker?

easy

A. docker run <container_name>

B. docker stop <container_name>

C. docker start <container_name>

D. docker restart <container_name>

Solution

1. Step 1: Understand the purpose of docker start

   This command resumes a container that was previously stopped without creating a new one.

2. Step 2: Differentiate from other commands

   docker run creates a new container, docker stop stops a running container, and docker restart stops then starts a container.

3. Final Answer:

   docker start <container_name> -> Option C

4. Quick Check:

   Start stopped container = docker start [OK]

Hint: Use 'docker start' to resume stopped containers fast [OK]

Common Mistakes:

• Confusing 'docker run' with 'docker start'
• Using 'docker stop' to start containers
• Thinking 'docker restart' only starts containers

2. Which of the following is the correct syntax to stop a running Docker container named webapp?

easy

A. docker terminate webapp

B. docker kill webapp

C. docker pause webapp

D. docker stop webapp

Solution

1. Step 1: Identify the command to safely stop a container

   docker stop sends a signal to gracefully stop the container.

2. Step 2: Check other options

   docker kill forcefully stops, docker pause suspends, and docker terminate is invalid.

3. Final Answer:

   docker stop webapp -> Option D

4. Quick Check:

   Stop container safely = docker stop [OK]

Hint: Use 'docker stop' to safely end container processes [OK]

Common Mistakes:

• Using 'docker kill' instead of 'docker stop'
• Confusing 'docker pause' with stopping
• Using non-existent commands like 'docker terminate'

3. What will be the output of the following commands if the container db is currently stopped?

docker start db
docker stop db

medium

A. Container 'db' starts, then stops successfully

B. Error: container 'db' not found

C. Container 'db' remains stopped

D. Container 'db' restarts automatically

Solution

1. Step 1: Analyze docker start db

   This command starts the stopped container named 'db'.

2. Step 2: Analyze docker stop db

   This command stops the running container 'db' safely.

3. Final Answer:

   Container 'db' starts, then stops successfully -> Option A

4. Quick Check:

   Start then stop container = success [OK]

Hint: Start then stop a container runs commands without error [OK]

Common Mistakes:

• Assuming 'docker start' creates a new container
• Expecting errors if container exists
• Thinking container restarts automatically without command

4. You run docker start myapp but get the error: Error response from daemon: No such container: myapp. What is the most likely cause?

medium

A. Docker daemon is not running

B. The container 'myapp' does not exist

C. You need to use docker run instead

D. The container 'myapp' is already running

Solution

1. Step 1: Understand the error message

   The error says 'No such container', meaning 'myapp' is not found in Docker's container list.

2. Step 2: Check other options

   If it was running, 'docker start' would not error; 'docker run' creates new containers but error is about missing container; daemon not running causes different errors.

3. Final Answer:

   The container 'myapp' does not exist -> Option B

4. Quick Check:

   No such container error = container missing [OK]

Hint: Check container existence before starting [OK]

Common Mistakes:

• Assuming container is running when error says missing
• Trying 'docker run' without checking container list
• Ignoring Docker daemon status

5. You want to stop a container named api-server but ensure it has 10 seconds to finish its work before stopping. Which command should you use?

hard

A. docker stop -t 10 api-server

B. docker kill -t 10 api-server

C. docker pause api-server

D. docker stop api-server -timeout 10

Solution

1. Step 1: Understand the timeout option in docker stop

   The -t or --time flag sets seconds to wait before killing the container.

2. Step 2: Evaluate the options

   docker kill does not support -t, docker pause only suspends, and -timeout is invalid syntax.

3. Final Answer:

   docker stop -t 10 api-server -> Option A

4. Quick Check:

   Stop with timeout = docker stop -t [OK]

Hint: Use 'docker stop -t seconds' to allow graceful shutdown [OK]

Common Mistakes:

• Using 'docker kill' with timeout flag
• Using invalid flags like '-timeout'
• Confusing 'pause' with stopping