Scaling services with replicas in Docker - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to scale the service named webapp to 3 replicas.

Docker

docker service scale webapp=[1]

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

A0

B3

C1

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using zero replicas which stops the service.

Using a number too high without resources.

The command docker service scale webapp=3 sets the number of replicas for the webapp service to 3.

2fill in blank

medium

Complete the command to create a service named api with 4 replicas using the image myapi:latest.

Docker

docker service create --name api --replicas [1] myapi:latest

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

A2

B1

C4

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to specify replicas, which defaults to 1.

Using an invalid number like zero or negative.

The option --replicas 4 tells Docker to start 4 copies of the api service.

3fill in blank

hard

Fix the error in the command to scale the service db to 2 replicas.

Docker

docker service scale [1]

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

A2

Bscale=2

Cdb 2

Ddb=2

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving a space instead of using '=' between service and number.

Adding extra words like 'scale=' which is not valid here.

The correct syntax is docker service scale db=2 where the service name and replica count are joined by an equal sign.

4fill in blank

hard

Fill both blanks to create a service named worker with 6 replicas using the image worker:stable.

Docker

docker service create --name [1] --replicas [2] worker:stable

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

Aworker

B6

Cweb

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up service name and replica count.

Using a wrong image name.

The service name is worker and the replicas count is 6.

5fill in blank

hard

Fill all three blanks to update the service cache to 5 replicas and use the image redis:6.

Docker

docker service update --image [1] --replicas [2] [3]

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

Aredis:6

B5

Ccache

Dredis:latest

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong image tags.

Putting service name in the wrong place.

The command updates the cache service to use image redis:6 and scale to 5 replicas.