Docker

Question 1

What type of service are containers and why?

Answer 1

Between LaaS and PaaS

Because we can customize the runtime

Question 2

What is a daemon?

Answer 2

A background process

Question 3

What is an image?

Answer 3

A particular runtime configuration

Question 4

What is a container?

Answer 4

A singular deployment of an image

Question 5

What is the command to deploy an image?

Answer 5

docker run -d -p 80:80 docker/name

Question 6

When using docker run what does the -p option mean?

Answer 6

Specifies the internal and external ports of the container

Question 7

When using docker run what does the -d option mean?

Answer 7

Use daemons

Question 8

What files do you need to create a Docker image?

Answer 8

Dockerfile

Question 9

In the Dockerfile what is the FROM command?

Answer 9

Specifies the base image and version to use

Question 10

In the Dockerfile what is the RUN command?

Answer 10

Run commands during the building of the image

Used for environment configuration

Question 11

In the Dockerfile what is the COPY command?

Answer 11

Copies files from your local filesystem into the images filesystem

COPY

Question 12

In the Dockerfile what is the EXPOSE command?

Answer 12

Specifies a port that we want to open

Question 13

In the Dockerfile what is the CMD command?

Answer 13

Run commands during the container initialization

Dockerfile can only have one CMD statement

Question 14

What is the command to build an image?

Answer 14

docker build -t alpineapache ../name

Question 15

What is the command to build an image?

Answer 15

docker build -t “alpineapache ../name”

Question 16

When using docker build what does the -t option mean?

Answer 16

Allows us to specify a name

Question 17

What is Docker Hub?

Answer 17

A remote repository hosted by Docker

Question 18

What is the command to push your image to DockerHub?

Answer 18

docker push username/repo

Question 19

What are tags used for?

Answer 19

Used to specify things like the underlying OS or version

Question 20

What is the command to build an image with a tag?

Answer 20

docker build -t “alpineapache ../name:tag” .

Question 21

What is the command to push your image to DockerHub with a tag?

Answer 21

docker push username/repo:tag

Question 22

What are multi-process containers?

Answer 22

multiple different processes running together in a single container

Question 23

What are multi-process containers good and bad for?

Answer 23

• Good for small deployments

- Bad for scalability

Question 24

What is container orchestration are what is it used with?

Answer 24

• Docker Compose

- Deploys multiple containers as a single service

Question 25

What are the pros of Docker Compose?

Answer 25

• Deploy & destroy containers all at once

- Containers communicate securely and quickly

Question 26

What files are needed to use Docker Compose?

Answer 26

docker-compose.yml

tells Docker what containers to run for our services

Question 27

Give an example of a docker-compose.yml file

Answer 27

services:
    webserver: 
        build:
        ports:
            - "80:777"

Question 28

In the Dockerfile what is the ENV command?

Answer 28

Set some environment variables the Flask web framework will use

Question 29

What is the command to run docker compose?

Answer 29

docker-compose up –build

Question 30

When using docker-compose what does –build mean?

Answer 30

Force Docker to rebuild images in your deployment

Question 31

What does the depends_on option?

Answer 31

Specifies when one service relies on another

depends_on:
- “redisserver”

Question 32

When using docker-compose what does this mean?

docker-compose up –build –scale webserver=3

Answer 32

Specify the number of instances to scale to

Question 33

What is the command to remove all currently stopped containers in Docker?

Answer 33

docker container prune