Containers Concepts

A container is a unit of software/deployment

Why containers?

• Move faster by deploying smaller units
• Use fewer resources
• Fit more into the same host
• Faster automation
• Portability
• Isolation

VM vs Containers

Virtual Machine	Container
Large footprint	Lightweight
Slow to boot	Quick to start (it does not have to boot)
Ideal for long running tasks	Ideal for short lived tasks
	Portable

⛔️ Containers are made of layers

Container Registry

Orchestrator

• Manage
  • Infrastructure
  • Containers
  • Deployment
  • Scaling
  • Failover
  • Health monitoring
  • App upgrades, Zero-Downtime deployments
• Install your own
  • Kubernetes, Swarm, Service Fabric
• Orchestrators as a service
  • Azure Kubernetes Service, Service Fabric

What is Docker

• An open source container runtime
• Mac, Windows & Linux support
• Command line tool
• "Dockerfile" file format for building container images
• Windows let your run Windows and Linux containers

Docker CLI Cheat Sheet - Management

docker info     # Display system information
docker version  # Display the system's version
docker login    # Log in to a Docker registry 

Docker Desktop

• Make sure you signed in to your Docker account.
• Enable kubernetes
  • Click on the Settings icon (gear) in the top right of the window.
  • Select Kubernetes.
  • Check Enable Kubernetes.

Docker CLI Cheat Sheet - Running Containers

docker pull [imageName]                            # Pull an image from a registry
docker run [imageName]                             # Run containers
docker run -d [imageName]                          # Detached mode
docker run --publish 80:80 --name webserver nginx  # pull and run an nginx server
docker start [containerName]                       # Start stopped containers
docker ps                                          # List running containers
docker ps -a                                       # List running and stopped containers
docker stop [containerName]                        # Stop containers
docker kill [containerName]                        # Kill containers
docker image inspect [imageName]                   # Get image info
docker rm [containerName]                          # remove the container

Docker CLI Cheat Sheet - Limits

docker run --memory="256m" nginx  # Set a maximum memory limit for the container
docker run --cpus=".5" nginx      # Set a maximum CPU limit for the container

Docker CLI Cheat Sheet - Attach Shell

docker run -it nginx -- /bin/bash                           # Attach shell to nginx container
docker run -it -- microsoft/powershell:nanoserver pwsh.exe  # Attach Powershell to a nanoserver container
docker container exec -it [containername] -- bash           # Attach to a running container's bash shell

Docker CLI Cheat Sheet - Cleaning Up

docker rm [containerName]             # Removes stopped containers
docker rm $(docker ps -a -q)          # Removes all stopped containers
docker images                         # Lists images
docker rmi [imageName]                # Deletes the image
docker system prune -a                # Removes all images not in use by any containers

Docker CLI Cheat Sheet - Building

docker build -t [name:tag] .             # Builds an image using a Dockerfile located in the same folder
docker build -t [name:tag] -f [fileName] # Builds an image using a Dockerfile located in a different folder
docker tag [imageName] [name:tag]        # Tag an existing image

Docker CLI Cheat Sheet - Tagging

docker tag => Create a target image
  - name:tag
    - myimage:v1
  - repository/name:tag
    - myacr.azurecr.io/myimage:v1