Concepts

Docker

• a container image format
• a container runtime library
• a cli tool
• an API for container mgmt

Image

• a single binary file
• has unique ID
• holds everything needed to run the container
• is completely specified by Dockerfile.

$ docker container run -p 9999:8888 --rm namespace/image:version

Dockerfile

• is a text file
• specifies exactly what needs to go into the container image
• has instructions from a starting image, transforming, and saving results as a new image.
• Minimize it!

FROM golang:1.11-alpine AS build
WORKDIR /src/
RUN go build -o /bin/demo
FROM scratch
COPY --from=build /bin/demo /bin/demo
ENTRYPOINT ["/bin/demo"]

$ docker image build -t myimage .

Registry

• a depot for pushing and pulling images.

Kubernetes

• for macOS users, run it from Docker for Mac > Preferences > Kubernetes > Enable Kubernetes.
• for Linux users, use minikube.

$ kubectl run demo \\
  --image=DOCKER_ID/myimage \\
  --port=9999 \\
  --labels app=demo

$ kubectl port-forward DOCKER_ID/demo 9999:8888

$ kubectl get po --selector=app=demo