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Summary - Image management

Combine pull, tag, push and rmi to manage the image lifecycle.

Summary: image management

In this group:

  • docker images lists local images; <none> is a dangling image.
  • docker rmi deletes; it's refused if a container uses the image. image prune (-a) cleans in bulk.
  • docker pull downloads in layers; --platform and digests are supported.
  • For docker push, the name must include the account/registry and docker login must be done.
  • docker tag adds a new name; save/load move images without a registry.
docker pull nginx:alpine
docker tag nginx:alpine ali/nginx:alpine
docker push ali/nginx:alpine
docker image prune -f

Practice Release a version

Write four commands: tag the api:3.0.0 image as ali/api:3.0.0 and ali/api:latest (two commands); push all tags of the ali/api repository; clean up dangling images without confirmation.

Starter code

terminal
# buraya yaz

Sample solution

terminal
docker tag api:3.0.0 ali/api:3.0.0
docker tag api:3.0.0 ali/api:latest
docker push --all-tags ali/api
docker image prune -f

Expected output

The push refers to repository [docker.io/ali/api]
3.0.0: digest: sha256:4a5b… size: 1789
latest: digest: sha256:4a5b… size: 1789
Total reclaimed space: 0B

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the way to move an image to a server without internet access?

  • docker tag
  • Write to tar with docker save and docker load on the server Correct answer
  • docker push
  • docker pull

Explanation: The tar file can be moved any way (scp, USB).

2 Load the image from a tar file.

Question 
docker load ____ api.tar
Answer 
docker load -i api.tar

Explanation: -i (input) gives the file to read.

3 Match.

Term Meaning
pull Download
push Upload
rmi Delete
prune Bulk clean

All lessons in Beginner

1 What is Docker?

  1. What is Docker?
  2. Containers and virtual machines
  3. Images and containers
  4. Docker architecture
  5. Use cases
  6. Summary - What is Docker

2 Installation and first commands

  1. Installing Docker
  2. docker version
  3. docker info
  4. The hello-world container
  5. Docker Desktop
  6. Summary - Installation

3 First container

  1. docker run basics
  2. Running in the background
  3. docker ps
  4. docker stop and rm
  5. docker logs
  6. Summary - First container

4 Dockerfile basics

  1. What is a Dockerfile?
  2. The FROM instruction
  3. The RUN instruction
  4. COPY and ADD
  5. CMD and ENTRYPOINT
  6. Summary - Dockerfile

5 Build and images

  1. docker build
  2. Tagging images
  3. Build context
  4. Layers and cache
  5. .dockerignore
  6. Summary - Build

6 docker run options

  1. Interactive mode
  2. Naming containers
  3. Restart policy
  4. Working directory
  5. Switching users
  6. Summary - docker run

7 Image management

  1. docker images
  2. docker rmi
  3. docker pull
  4. docker push
  5. docker tag
  6. Summary - Image management

8 Port mapping

  1. The port concept
  2. The -p flag
  3. Multiple ports
  4. Random ports
  5. IP binding
  6. Summary - Port mapping

9 Volumes and data

  1. Data persistence
  2. Named volumes
  3. The -v flag
  4. Bind mounts
  5. Volume management
  6. Summary - Volumes

10 Environment variables

  1. The -e flag
  2. The ENV instruction
  3. The ARG instruction
  4. env-file
  5. The WORKDIR instruction
  6. Summary - Environment

11 Project: docker-compose

  1. Compose design
  2. Service definition
  3. Database service
  4. Volume and network
  5. Putting it together - compose

12 Docker Hub and registry

  1. What is Docker Hub?
  2. docker login
  3. Searching images
  4. Official images
  5. Private registry
  6. Summary - Registry

13 Network basics

  1. Network drivers
  2. docker network ls
  3. Bridge network
  4. Container connectivity
  5. Publishing ports
  6. Summary - Network

14 Beginner final

  1. Challenge - Dockerfile
  2. Challenge - Build and run
  3. Challenge - Volume
  4. Challenge - Compose
  5. Challenge - Beginner project