docker-containers

Various Docker build scripts for different projects and related stuff.

Install Docker

The easiest way is to use the 'get-docker' script from: https://github.com/docker/docker-install

curl -fsSL https://get.docker.com -o get-docker.sh
sh get-docker.sh

Docker Container Lifecycle

The lifecycle of a Docker image/container: pull -> run -> stop -> remove -> delete

Good to know:

• A stopped container keeps its state and can be started again (internal programs are closed though).
• To fully reset a container it needs to be stopped and removed.
• The state of a running or stopped container can be made permanent via a commit.
• Commits create additional layers that can increase the container size significantly.
• Commits will ignore external data from volumes
• If you create a volume using an empty folder (host) and connect it to a container folder that is not empty (-v flag) it will be filled with the container data at first run. This ONLY works for named volumes.

Useful commands / Cheat Sheet

Some variables used in cheat sheet:

• [image-tag]: The tag or "name" of an image, e.g. myrepo/myimage:latest
• [container-name]: If you run an image you give it a name (with the --name flag), e.g. my_container. If you don't define a name Docker will create a random one.

Basics

• get image: sudo docker pull [image-tag]
• show images: sudo docker images
• show active (running or stopped) containers: sudo docker container ls
• remove stopped container: sudo docker rm [container-name]
• remove all stopped containers: sudo docker images prune
• delete image: sudo docker rmi [image-tag]
• get config info about image: sudo docker inspect [image-tag]

Build and Update

• build Dockerfile: sudo docker build -t [new-image-tag] .
• build Dockerfile without cache: sudo docker build --no-cache -t [new-image-tag] .
• commit changes: sudo docker commit [container-name] [new-image-tag]
• rename image: sudo docker image tag [old-image-tag] [new-image-tag]

Run, Enter and Stop

• run with bash: sudo docker run -it --name [container-name] -p [port-outside]:[port-inside] [image-tag]
• run with bash (overwrite entrypoint): sudo docker run -it --name [container-name] --entrypoint=/bin/bash [image-tag]
• run with volume and auto-remove: sudo docker run --rm -it -v [volume-name/folder-outside]:[folder-inside] [image-tag]
• run with ENV variable (e.g for internal settings): sudo docker run --env VAR1=value1 [image-tag]
• run container in background: sudo docker run --rm -d [image-tag]
• enter running container via bash: sudo docker exec -it [container-name] /bin/bash
• stop background container: sudo docker stop [container-name]
• restart a stopped container: sudo docker start [container-name]

Volumes

• list all volumes: sudo docker volume ls
• create a volume: sudo docker volume create --opt type=none --opt device=[host-folder] --opt o=bind [volume-name]
• remove a volume: sudo docker volume rm [volume-name]

Upload

• login to default registry (e.g. Docker-HUB): sudo docker login --username=[my-user]
• push image: sudo docker image push [image-tag]
• logout of registry: sudo docker logout

Create Manifest

• create: sudo docker manifest create [common-image-tag] --amend [image-tag-A] --amend [image-tag-B] ...
• upload: sudo docker manifest push [common-image-tag]