Why resource limits matter in Docker - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the command to limit the CPU usage of a Docker container to 50%.

Docker

docker run --cpus=[1] alpine top

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

A2

B0.5

C1

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using an integer greater than 1 to limit CPU to less than one core.

Omitting the --cpus flag.

The --cpus option limits the CPU usage. Setting it to 0.5 means the container can use up to 50% of one CPU.

2fill in blank

medium

Complete the command to limit the memory usage of a Docker container to 256 megabytes.

Docker

docker run --memory=[1] alpine top

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

A256mbs

B256mb

C256m

D256

Attempts:

3 left

💡 Hint

Common Mistakes

Using mb or mbs which are invalid units.

Not specifying any unit, which defaults to bytes and is too small.

The --memory option limits the memory. The correct suffix for megabytes is m, so 256m means 256 megabytes.

3fill in blank

hard

Fix the error in the command that tries to limit memory but uses an invalid unit.

Docker

docker run --memory=[1] alpine top

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

A512m

B512mb

C512mbs

D512

Attempts:

3 left

💡 Hint

Common Mistakes

Using mb or mbs as units.

Omitting the unit entirely.

The correct memory unit is m for megabytes. 512m is valid, while 512mb or 512mbs are invalid.

4fill in blank

hard

Fill both blanks to limit CPU to 1.5 cores and memory to 1 gigabyte.

Docker

docker run --cpus=[1] --memory=[2] alpine top

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

A1.5

B1g

C1.0g

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1.0g which is valid but less common.

Using 2 for memory which lacks a unit.

--cpus=1.5 limits CPU to one and a half cores. --memory=1g limits memory to 1 gigabyte.

5fill in blank

hard

Fill all three blanks to run a container with CPU limit 0.75, memory limit 512 megabytes, and a restart policy of always.

Docker

docker run --cpus=[1] --memory=[2] --restart=[3] alpine top

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

A0.75

B512m

Calways

Don-failure

Attempts:

3 left

💡 Hint

Common Mistakes

Using 512mb instead of 512m.

Using on-failure when the question asks for always.

The CPU limit is 0.75, memory limit is 512m for 512 megabytes, and the restart policy always makes the container restart automatically if it stops.