Inspecting Resources

Viewing Image Repositories

Retrieve a list of all image objects available locally.

docker images --all

Monitoring Active Containers

List currently running instances to verify status and obtain identifiers.

docker ps -a

The output displays the Container ID in the first column, which is required for subsequent operations.

Mdoifying Images

Committing Runtime Changes

Capture the current state of a container as a new image artifact. This is useful for saving temporary configurations or dependencies.

docker commit \
  -m="Applied security patches" \
  --author "dev-team@example.com" \
  container-7f8a9b0c custom-app:v2.1

Parameters:

• -m: Description string summarizing changes.
• --author: Email or name identifying the creator.
• container-id: Target idantifier from an active container.
• image-name:tag: Destination name and version tag for the new image.

Lifecycle Management

Instantiating Instances

Launch a new process based on a specific image with configuration overrides.

docker run -d \
  --name web-service \
  -v /opt/data:/var/www/html \
  -p 3000:80 \
  python:3.9-slim \
  tail -f /dev/null

Configuration Breakdown:

• -d: Detached mode (runs in background).
• --name: Assigns a human-readable alias (web-service).
• -v: Bind mounts host directory /opt/data into container path /var/www/html.
• -p: Maps host port 3000 to container port 80.
• Image reference python:3.9-slim specifies the base environment.

Interactive Access

Enter the shell of a running instance for debugging or administration.

docker exec -it web-service bash

Termination and Removal

Stop a specific instance and purge its filesystem data.

docker stop web-service
docker rm web-service

Image Tagging and Cleanup

Renaming References

Update tags without duplicating underlying layers.

docker tag old-repo/app:v1 latest-staging/app:v1

Removing Artifacts

Force delete a untagged or referenced image layer.

docker rmi -f old-repo/app:v1