Docker Flashcards
What type of service are containers and why?
Between LaaS and PaaS
Because we can customize the runtime
What is a daemon?
A background process
What is an image?
A particular runtime configuration
What is a container?
A singular deployment of an image
What is the command to deploy an image?
docker run -d -p 80:80 docker/name
When using docker run what does the -p option mean?
Specifies the internal and external ports of the container
When using docker run what does the -d option mean?
Use daemons
What files do you need to create a Docker image?
Dockerfile
In the Dockerfile what is the FROM command?
Specifies the base image and version to use
In the Dockerfile what is the RUN command?
Run commands during the building of the image
Used for environment configuration
In the Dockerfile what is the COPY command?
Copies files from your local filesystem into the images filesystem
COPY
In the Dockerfile what is the EXPOSE command?
Specifies a port that we want to open
In the Dockerfile what is the CMD command?
Run commands during the container initialization
Dockerfile can only have one CMD statement
What is the command to build an image?
docker build -t alpineapache ../name
What is the command to build an image?
docker build -t “alpineapache ../name”
When using docker build what does the -t option mean?
Allows us to specify a name
What is Docker Hub?
A remote repository hosted by Docker
What is the command to push your image to DockerHub?
docker push username/repo
What are tags used for?
Used to specify things like the underlying OS or version
What is the command to build an image with a tag?
docker build -t “alpineapache ../name:tag” .
What is the command to push your image to DockerHub with a tag?
docker push username/repo:tag
What are multi-process containers?
multiple different processes running together in a single container
What are multi-process containers good and bad for?
- Good for small deployments
- Bad for scalability
What is container orchestration are what is it used with?
- Docker Compose
- Deploys multiple containers as a single service
What are the pros of Docker Compose?
- Deploy & destroy containers all at once
- Containers communicate securely and quickly
What files are needed to use Docker Compose?
docker-compose.yml
tells Docker what containers to run for our services
Give an example of a docker-compose.yml file
services:
webserver:
build:
ports:
- "80:777"In the Dockerfile what is the ENV command?
Set some environment variables the Flask web framework will use
What is the command to run docker compose?
docker-compose up –build
When using docker-compose what does –build mean?
Force Docker to rebuild images in your deployment
What does the depends_on option?
Specifies when one service relies on another
depends_on:
- “redisserver”
When using docker-compose what does this mean?
docker-compose up –build –scale webserver=3
Specify the number of instances to scale to
What is the command to remove all currently stopped containers in Docker?
docker container prune
