Docker

Docker Copy Directory

• Create a Directory to Copy
• Alter the Dockerfile
• Create a Docker Image
• Docker Image Verification
• Docker Container Execution
• Check that the directory has been copied correctly.

Docker vs Kubernetes vs Jenkins

• Jenkins is a CI/CD model that can run, build, and test the application, whereas Docker is a container engine that creates and manages containers. Kubernetes is a container orchestration solution that uses continuous integration and delivery to automate computer programs.
• Kubernetes has a maximum of 5000 nodes, while Docker Swarm has a limit of 2000+ nodes. The number of Jenkins jobs/nodes is determined by the number of masters and slaves selected as a limit. It has no fixed limit and is changeable.
• Docker is a technology stack that allows you to create and execute many transportable environments. Jenkins is an app's automated software testing tool. Kubernetes, on the other hand, is a system that automates deployment, scalability, and management. In other words, containerized application orchestration.

Docker Cache Clean

• Removing unused containers

• • get the IDs of the containers with status exited or dead

• • • docker ps --filter status=exited --filter status=dead -q

• • reuse the above command to delete these containers

• • • docker rm $(docker ps --filter=status=exited --filter=status=dead -q)

• • one-liner alternative to remove all stopped containers

• • • docker container prune

• Removing all containers

• • stop all running containers and get the IDs of the running containers

• • • docker ps -q

• • stop all the containers with

• • • docker stop $(docker ps -q)

• • delete all containers

• • • docker rm $(docker ps -a -q)
• Removing dangling images
  • get the image ID for such images
    • docker images --filter dangling=true -q
  • delete those images with the following command
    • docker rmi $(docker images --filter dangling=true -q)
  • one-liner alternative to remove all dangling images
    • docker image prune
• Removing all images
  • need the IDs of all the images
    • docker images -a -q
  • combine it with docker rmi
    • docker rmi $(docker images -a -q)
  • one-liner alternative to remove all images
    • docker image prune -a

PlexTraktSync Docker

• The watched status is synchronized (dates are not reported from Trakt to Plex)
• You can pick what to sync by editing the config file.
• Plex media is added to the Trakt collection.
• Trakt liked lists are downloaded, and all movies from that list are put to Plex.
• The ratings are synchronized (if ratings differ, Trakt takes precedence)

Docker Failed to Initialize

• Docker should not be included in the "Add or remove programs" list.
• Restart your computer.
• With administrator credentials, install Docker (and never by operating the installer instantly)

• Launch Docker Services.
• Switch Hyper-V and Containers on.
• Type Windows Feature into the Windows search box, then click Turn Windows options on or off.
• Click OK after selecting Containers and Hyper-V 
• To see if Virtualization is enabled, go to Task Manager.

Docker Invalid Reference Format

• If you used variables such as ubuntu:$VERSION, $VERSION is not set. Make that $VERSION is set to a proper (non-empty) value, such as latest or 18.04!
• Because the command line inputs were mixed up, another argument was read as the image name.
• At the end of the picture name, you inserted a colon.
• You used a lot of colons.
• At the end of the image name, you inserted a dash.

Docker Questions and Answers

• Starting with the Python 3.7 image, create an image.
• Change to the /code directory as the working location.
• Set the environment variables that the flask command will use.
• GCC and other prerequisites must be installed.
• Install Python dependencies by copying requirements.txt.
• To explain that the container is listening on port 5000, add information to the image.
• Copy the current directory from the project to the image’s workdir.
• Set flask run as the container’s default command.

• Use Docker as your app’s operating system’s version control system.
• Use Docker to share and collaborate on your app’s operating system with a group.