Docker events for real-time monitoring - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to start real-time monitoring of Docker events.

Docker

docker [1]

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

Aevents

Brun

Cps

Dlogs

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'docker run' instead of 'docker events'.

Confusing 'docker logs' with event monitoring.

The docker events command shows real-time events from the Docker server.

2fill in blank

medium

Complete the command to filter Docker events by container ID.

Docker

docker events --filter 'container=[1]'

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

Avolume_name

Bimage_name

Cnetwork_name

Dcontainer_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using image name instead of container ID for filtering.

Trying to filter by network or volume names.

The --filter 'container=container_id' option filters events for a specific container.

3fill in blank

hard

Fix the error in the command to show Docker events for the last 10 seconds.

Docker

docker events --since [1]

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

Alast10

B10seconds

C10s

Dnow-10

Attempts:

3 left

💡 Hint

Common Mistakes

Using unsupported time formats like '10seconds' or 'last10'.

Using relative time expressions not recognized by Docker.

The --since option accepts a duration like 10s for 10 seconds.

4fill in blank

hard

Fill both blanks to filter Docker events by event type and since a specific time.

Docker

docker events --filter 'event=[1]' --since [2]

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

Astart

Bstop

C5m

D1h

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing event types and time formats incorrectly.

Using unsupported time strings.

Use --filter 'event=start' to see start events and --since 5m to limit to last 5 minutes.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps container IDs to event types for events since 1 hour.

Docker

events_dict = [1]: [2] for [3] in events if event['time'] > '1h ago'

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

Aevent['container_id']

Bevent['type']

Cevent

Dcontainer

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong keys or values in the dictionary.

Incorrect variable names in the loop.

This comprehension creates a dictionary with container IDs as keys and event types as values, iterating over each event.

Practice

1. What is the primary purpose of the docker events command?

easy

A. To show real-time activity and changes in Docker objects

B. To list all Docker images available locally

C. To start a new Docker container

D. To remove unused Docker volumes

Solution

1. Step 1: Understand the command's function

   The docker events command streams live events related to Docker objects like containers, images, and networks.

2. Step 2: Compare with other Docker commands

   Commands like docker images, docker run, and docker volume prune serve different purposes unrelated to real-time event monitoring.

3. Final Answer:

   To show real-time activity and changes in Docker objects -> Option A

4. Quick Check:

   docker events = real-time Docker activity [OK]

Hint: Remember: events = live Docker activity stream [OK]

Common Mistakes:

• Confusing events with listing images
• Thinking it starts containers
• Assuming it cleans volumes

2. Which of the following is the correct syntax to show Docker events filtered by container ID abc123?

easy

A. docker events --filter container=abc123

B. docker events -c abc123

C. docker events --container abc123

D. docker events filter container abc123

Solution

1. Step 1: Recall Docker events filter syntax

   The correct filter syntax uses --filter key=value, so filtering by container ID is --filter container=abc123.

2. Step 2: Check other options for syntax errors

   Options B, C, and D use incorrect flags or missing dashes, making them invalid commands.

3. Final Answer:

   docker events --filter container=abc123 -> Option A

4. Quick Check:

   Filter syntax = --filter key=value [OK]

Hint: Use --filter key=value to filter events [OK]

Common Mistakes:

• Using short flags like -c which don't exist
• Omitting --filter or using wrong flag names
• Writing filter without dashes

3. What will be the output of the command docker events --filter event=start --filter container=mycontainer --since 10m?

medium

A. Shows all events for all containers in the last 10 minutes

B. Shows only start events for container 'mycontainer' from last 10 minutes

C. Shows stop events for container 'mycontainer' from last 10 minutes

D. Shows start events for all containers since 10 minutes ago

Solution

1. Step 1: Analyze the filters used

   The command filters events by event=start and container=mycontainer, so only start events for that container are shown.

2. Step 2: Understand the time filter

   The --since 10m option limits events to those in the last 10 minutes.

3. Final Answer:

   Shows only start events for container 'mycontainer' from last 10 minutes -> Option B

4. Quick Check:

   Filters combine to narrow events [OK]

Hint: Multiple --filter options combine to narrow events [OK]

Common Mistakes:

• Ignoring the container filter
• Confusing event=start with stop
• Misunderstanding --since time filter

4. You run docker events --filter event=stop --filter container=webapp but see no output even though the container stopped recently. What is the likely cause?

medium

A. The docker events command does not support filtering

B. The container never stopped

C. The container name is incorrect or misspelled

D. You need to add --since to see recent events

Solution

1. Step 1: Verify container name correctness

   If the container name is wrong or misspelled, no matching events will appear.

2. Step 2: Check command capabilities and event timing

   The docker events command supports filtering, and recent stop events should show without --since if they happened after the command started.

3. Final Answer:

   The container name is incorrect or misspelled -> Option C

4. Quick Check:

   Correct container name needed for filtering [OK]

Hint: Check container name spelling when no events appear [OK]

Common Mistakes:

• Assuming filtering is unsupported
• Forgetting container names are case-sensitive
• Thinking --since is always required

5. You want to monitor Docker events for container dbserver and automatically trigger a script when it stops. Which command correctly streams only stop events for that container?

hard

A. docker events --container=dbserver --event=stop

B. docker events --filter event=stop --container dbserver

C. docker events --filter stop --filter container=dbserver

D. docker events --filter container=dbserver --filter event=stop

Solution

1. Step 1: Use correct filter syntax for container and event

   The correct syntax uses --filter key=value. So --filter container=dbserver and --filter event=stop are valid.

2. Step 2: Identify invalid options

   Options B, C, and D use incorrect flags like --container or missing event= format, which are invalid.

3. Final Answer:

   docker events --filter container=dbserver --filter event=stop -> Option D

4. Quick Check:

   Use --filter key=value for all filters [OK]

Hint: Always use --filter key=value for event and container filters [OK]

Common Mistakes:

• Using --container or --event flags incorrectly
• Omitting 'event=' or 'container=' in filters
• Mixing filter syntax with invalid flags