1 Docker CheatSheet

• PDF Link: cheatsheet-docker-A4.pdf, Category: Cloud
• Blog URL: https://cheatsheet.dennyzhang.com/cheatsheet-docker-A4
• Related posts: Kubernetes Yaml, #denny-cheatsheets

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1.1 Docker Trouble Shooting

Name	Summary
Docker push: manifest invalid	Re-push a new version of the same docker tag may fail, due to permission
Docker pull: missing signature key	Docker push again to resolve the issue
Docker cp: Error response from daemon: not a directory	container folder is in a symbol link
Find process id by container name	docker top $container_id, or docker top $container_name
List resource usage by containers	docker stats
Get dockerd storage driver	docker info, then check Storage Driver
docker-containerd-shim	The Docker four components: Docker engine, containerd, containerd-shm and runC

1.2 Docker Basic

Name	Summary
Install docker on Ubuntu	apt-get install docker.io
Install docker on CentOS	Use docker repo https://download.docker.com/linux/centos/docker-ce.repo
Install docker in Debian 10	Link: How To Install and Use Docker on Debian 10
Install old docker version	GitHub: install-old-docker.md

1.3 Docker start service

Name	Summary
Start a ubuntu test env	docker run ubuntu:16.04 /bin/echo hello world
Start a ubuntu 18.04 test env	docker run ubuntu:18.04 /bin/echo hello world
Start a container run and stop	docker run --rm ubuntu:18.04 /bin/echo hello world
Start a debian9 test env	docker run debian:9 /bin/echo hello world
Start a centos test env	docker run centos:centos6 /bin/echo hello world
Start a jenkins server	docker run -p 8080:8080 -p 50000:50000 jenkins/jenkins:lts
Start a nginx server	docker run -t -d -p 8080:80 --name nginx-test nginx
Start a mysql server	docker run -e MYSQL_ROOT_PASSWORD=password123 -e MYSQL_DATABASE=wordpress -d mysql:5.7
Start a nexus server	docker run -d -p 8082:8081 --name nexus -v /data/nexus-data:/nexus-data sonatype/docker-nexus3
Start a sshd server	docker run -t -d --privileged -p 5022:22 denny/sshd:latest /usr/sbin/sshd -D
Start a ftp server	docker run -t -d -p 21:21 -p 20:20 -e USERNAME=${username} -e PASSWORD=${password} denny/proftproftpd:v1

1.4 Container Runtime

Name	Summary
dockerd
containerd
cri-o	From Redhat
rkt	a pod-native container engine for Linux from CoreOS. Stopped maintainance now
Amazon ACS	supports DC/OS, Swarm, Kubernetes
CoreOS Fleet
Cloud Foundry Diego	Not actively maintained any more
Reference	CheatSheet: Docker, CheatSheet: CRI-O, CheatSheet: rkt, CheatSheet: containerd

1.5 Container Basic

Name	Summary
Start docker container	docker run -p 4000:80 imgname
Start docker container in detached mode	docker run -d -p 4000:80 imgname
Start container with entrypoint changed	=docker run -t -d –entrypoint=/bin/sh “$docker_image”=
Enter a running container	docker exec -it <container-id> sh
Upload local file to container filesystem	docker cp /tmp/foo.txt mycontainer:/foo.txt
Download container file local filesystem	docker cp mycontainer:/foo.txt /tmp/foo.txt
Stop container	docker stop <hash>
Remove container	docker rm <hash>
Remove all containers	docker rm $(docker ps -a -q)
Force shutdown of one given container	docker kill <hash>
Login to docker hub	docker login
Tag <image>	docker tag <image> username/repo:tag
Docker push a tagged image to repo	docker push username/repo:tag
Run image from a given tag	docker run username/repo:tag
Create docker image	docker build -t denny/image:test .

1.6 Docker Cleanup

Name	Summary
Remove unused docker images	delete-unused-images.sh
Delete all containers	delete-all-containers.sh
Remove exited containers	docker rm $(docker ps --filter status=exited -qa)
Docker prune images	docker image prune -f
Docker prune volumes	docker volume prune -f
Remove the specified image	docker rmi <imagename>
Remove all docker images	docker rmi $(docker images -q)
Remove orphaned docker volumes	docker volume rm $(docker volume ls -qf dangling=true)
Remove dead containers	docker rm $(docker ps --filter status=dead -qa)

1.7 Dockerfile

Name	Summary
Change entrypoint to run nothing	entrypoint: ["tail", "-f", "/dev/null"]
Set timezone in Dockerfile	RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
Define multiple line command	GitHub: Dockerfile-example-multiline

1.8 Docker Compose

Name	Summary
Change restart policy	restart: always, Link: Compose file version 3 reference
Mount file as volume	$PWD/httpd/httpd.conf:/usr/local/apache2/conf/httpd.conf:ro GitHub: sample-mount-file.yml
Start compose env	docker-compose up, docker-compose up -d
Stop compose env	docker-compose down, docker-compose down -v
Check logs	docker-compose logs

1.9 Docker Containers

Name	Summary
Start docker container	docker run -p 4000:80 <imgname>
Start docker container in detached mode	docker run -d -p 4000:80 imgname
Start docker container and remove when exit	docker run -rm -it <imgname> sh
Enter a running container	docker exec -it [container-id] sh
Stop container	docker stop <hash>
List all containers	docker ps, docker ps -a
Remove container	docker rm <hash>, docker rm $(docker ps -a -q)
Force shutdown of one given container	docker kill <hash>
Login to docker hub	docker login
Run image from a given tag	docker run username/repo:tag
Tail container logs	docker logs --tail 5 $container_name
Check container healthcheck status	docker inspect --format '{{.State.Health}}' $container_name
List containers by labels	=docker ps –filter “label=org.label-schema.group”=

1.10 Docker Images

Name	Summary
List all images	docker images, docker images -a
Create docker image	docker build -t denny/image:<tag> .
Docker push a tagged image to repo	docker push denny/image:<tag>
Show the history of an image	docker history <image_name>
Export image to file	docker save <image_name> > my_img.tar
Load image to local registry	docker load -i my_img.tar
Tag <image>	docker tag <image> username/repo:tag

1.11 Docker Socket file

Name	Summary
Run container mounting socket file	docker run -v /var/run/docker.sock:/var/run/docker.sock -it alpine sh
A different docker socket file	export DOCKER_HOST=unix:///my/docker.sock
List containers	curl -XGET --unix-socket /var/run/docker.sock http://localhost/containers/json
Stop container	curl -XPOST --unix-socket /var/run/docker.sock http://localhost/containers/<container_id>/stop
Start container	curl -XPOST --unix-socket /var/run/docker.sock http://localhost/containers/<container_id>/start
List events	curl --unix-socket /var/run/docker.sock http://localhost/events
Create container	curl -XPOST --unix-socket /var/run/docker.sock -d '{"Image":"nginx:alpine"}' -H 'Content-Type: application/json' http://localhost/containers/create
Links	Link: Develop with Docker Engine SDKs and API

1.12 Docker Conf

Name	Summary
Docker files	/var/lib/docker, /var/lib/docker/devicemapper/mnt
Docker for Mac	~/Library/Containers/com.docker.docker/Data/

1.13 Ubuntu docker: Install missing packages

Name	Summary
Pull ubuntu docker image	docker pull ubuntu
man: command not found	apt-get update, apt-get install man
ping: command not found	apt-get update, apt-get install iputils-ping
dig: command not found	apt-get install dnsutils

1.14 Check Status

Name	Summary
Tail container logs	docker logs --tail 5 $container_name
Check container healthcheck status	docker inspect --format '{{.State.Health}}' $container_name
List containers	docker ps
List all containers	docker ps -a
List containers by labels	=docker ps –filter “label=org.label-schema.group”=
List all images	docker images -a

1.15 Resource Reference

Name	Summary
Docker SDK	https://docs.docker.com/develop/sdk/examples/
Docker REST API	https://docs.docker.com/engine/api/v1.27/#tag/Container
Docker Hub auto build	https://docs.docker.com/docker-hub/builds/#build-statuses-explained

1.16 More Resources

License: Code is licensed under MIT License.

2 TODO docker ARG vs ENV

https://github.com/JCMais/docker-linux-ci/blob/master/debian.dockerfile#L15-L16