Container resource usage stats in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to show real-time resource usage stats of all containers.

Docker

docker stats [1]

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

A--no-stream

B--all

C--format

D--quiet

Attempts:

3 left

💡 Hint

Common Mistakes

Using --no-stream which only shows a single snapshot

Using --quiet which suppresses output

The --all option shows stats for all containers, including non-running ones.

2fill in blank

medium

Complete the command to show a single snapshot of container stats without continuous updates.

Docker

docker stats [1]

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

A--no-stream

B--no-trunc

C--format

D--all

Attempts:

3 left

💡 Hint

Common Mistakes

Using --all which shows all containers but still streams

Using --format which changes output format but not streaming

The --no-stream option shows only one snapshot of stats and then exits.

3fill in blank

hard

Fix the error in the command to display CPU and memory usage in a custom format.

Docker

docker stats --format "{{.Name}}: CPU [1], MEM {{.MemUsage}}"

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

A{{.CPUPerc}}

B{{.MemUsage}}

C{{.ID}}

D{{.Name}}

Attempts:

3 left

💡 Hint

Common Mistakes

Using {{.MemUsage}} for CPU which shows memory instead

Using {{.Name}} or {{.ID}} which are container identifiers

The placeholder {{.CPUPerc}} correctly shows CPU percentage usage.

4fill in blank

hard

Fill both blanks to create a command that shows stats only for containers named 'webapp' and 'db'.

Docker

docker stats [1] [2]

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

Awebapp

Bdb

C--no-stream

D--all

Attempts:

3 left

💡 Hint

Common Mistakes

Using options like --all or --no-stream instead of container names

Mixing container names with options in wrong order

Specifying container names after docker stats limits stats to those containers.

5fill in blank

hard

Fill all three blanks to format output showing container name, CPU %, and memory usage.

Docker

docker stats --format "[1]: CPU [2], MEM [3]"

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

A.Name

B{{.CPUPerc}}

C{{.MemUsage}}

D.ID

Attempts:

3 left

💡 Hint

Common Mistakes

Using .ID instead of .Name for container name

Omitting braces or dots in placeholders

{{.Name}} shows container name, {{.CPUPerc}} CPU usage, and {{.MemUsage}} memory usage.

Practice

1. What does the docker stats command show you?

easy

A. Docker network settings

B. Real-time resource usage like CPU and memory of containers

C. Logs of a running container

D. List of all Docker images on the system

Solution

1. Step 1: Understand the purpose of docker stats

   This command is designed to show resource usage statistics of running containers.

2. Step 2: Identify what resource stats include

   It shows CPU, memory, network IO, and block IO usage in real time.

3. Final Answer:

   Real-time resource usage like CPU and memory of containers -> Option B

4. Quick Check:

   docker stats = resource usage [OK]

Hint: Remember: stats = resource usage snapshot [OK]

Common Mistakes:

• Confusing stats with logs
• Thinking it lists images
• Assuming it shows network config

2. Which of these is the correct syntax to get a one-time snapshot of container stats for container named webapp?

easy

A. docker stats --no-stream webapp

B. docker stats webapp

C. docker stats --once webapp

D. docker stats webapp --snapshot

Solution

1. Step 1: Recall the correct option for one-time snapshot

   The flag --no-stream disables continuous updates and shows a single snapshot.

2. Step 2: Check correct command order

   The flag --no-stream should come before the container name webapp.

3. Final Answer:

   docker stats --no-stream webapp -> Option A

4. Quick Check:

   One-time stats = --no-stream before container [OK]

Hint: Use --no-stream before container name for snapshot [OK]

Common Mistakes:

• Using wrong flag like --once or --snapshot
• Omitting the --no-stream flag
• Omitting container name

3. What output will you get when running docker stats --no-stream with two running containers named db and cache?

medium

A. A single snapshot table showing CPU, memory, and IO stats for db and cache

B. An error saying container names are missing

C. A live updating table of resource usage for db and cache containers

D. Only stats for the first container found

Solution

1. Step 1: Understand the effect of --no-stream flag

   This flag disables live updates and shows only one snapshot of stats.

2. Step 2: Check default behavior without container names

   Without specifying containers, stats shows all running containers, here db and cache.

3. Final Answer:

   A single snapshot table showing CPU, memory, and IO stats for db and cache -> Option A

4. Quick Check:

   --no-stream + multiple containers = single snapshot for all [OK]

Hint: No container names + --no-stream = snapshot for all running [OK]

Common Mistakes:

• Expecting live updates with --no-stream
• Thinking container names are required
• Assuming only one container stats shown

4. You run docker stats --no-stream mycontainer but get an error: no such container: mycontainer. What is the likely cause?

medium

A. Docker daemon is not running

B. The --no-stream flag is not supported

C. The container name is misspelled or does not exist

D. You need to add --all flag to see stopped containers

Solution

1. Step 1: Analyze the error message

   The error says container not found, so the name is likely wrong or container is not running.

2. Step 2: Check other options

   --no-stream is valid, Docker daemon error would be different, and --all is not for stats command.

3. Final Answer:

   The container name is misspelled or does not exist -> Option C

4. Quick Check:

   Container not found error = wrong name [OK]

Hint: Check container name spelling if 'no such container' error [OK]

Common Mistakes:

• Assuming --no-stream causes error
• Ignoring Docker daemon status
• Thinking --all shows stats for stopped containers

5. You want to monitor CPU and memory usage of a container named api-server but only want a single snapshot, not continuous updates. Which command should you use and why?

hard

A. docker stats api-server --interval=1 to update every second

B. docker stats api-server because it shows live updates by default

C. docker stats --all api-server to include stopped containers

D. docker stats --no-stream api-server because it shows one-time resource usage snapshot

Solution

1. Step 1: Identify the need for a single snapshot

   Using --no-stream disables continuous updates and shows one snapshot.

2. Step 2: Confirm container name usage

   Specify the container name api-server to get stats only for it.

3. Step 3: Evaluate other options

   Default docker stats streams live updates, --all is invalid here, and --interval is not a valid flag.

4. Final Answer:

   docker stats --no-stream api-server because it shows one-time resource usage snapshot -> Option D

5. Quick Check:

   Single snapshot = --no-stream with container name [OK]

Hint: Use --no-stream with container name for single snapshot [OK]

Common Mistakes:

• Omitting --no-stream for single snapshot
• Using invalid flags like --all or --interval
• Expecting live updates when not wanted