Docker

• add user to docker group to remove permission issues:

sudo usermod -aG docker $USER
# login in the group to avoid reboot
newgrp docker

• build image: docker build -t <image_name> .
• tag image: docker tag example_image:latest gauravvv/example_image:latest
• push image: docker push gauravvv/example_image:latest
• stop auto-restart: docker update --restart=no my-container
• delete images with filter: docker image prune -a --filter "until=24h"
• save image to tar: docker save -o file.tar image_name
• load image from tar: docker load -i file.tar
• check images checksum: docker images --digests

system

• check disk space usage: docker system df

tips for production

• for performance use option --net host

context

• docker context:
• create Create a context
• export Export a context to a tar or kubeconfig file
• import Import a context from a tar or zip file
• inspect Display detailed information on one or more contexts
• ls List contexts
• rm Remove one or more contexts
• update Update a context
• use Set the current docker context

dockerfile

• CMD: specifies the default command to run when a container is started
• example: ["python", "app.py"]
• ENTRYPOINT: specifies the executable that will be run when the container is started, any arguments passed to docker run will be passed as arguments to ENTRYPOINT executable

logs

• logs are stored here: /var/lib/docker/containers/CONTAINER_ID/CONTAINER_ID-json.log
• control log size and number of files: docker run --log-opt max-size=10m --log-opt max-file=3 my_image