Pushplaybang/docker-basics.md

## docker-basics.md

      
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              docker-basics.md
            
          
    MY Docker Cheat Sheet

a breif selection of essential commands, tips and notes about working with docker, as a personal reference. use at your own risk.
Working with containers

create and start a container

docker run [-a] <container-name> <override>

essentially runs the following two commands

docker create <container-name> <override>
docker start [-a] <container-id>

list all running containers

docker ps

list all containers

docker ps --all

delete everything

docker system prune

output logs for a running container

docker logs <container-id>

gracefully stop a running container

docker stop <container-id>

forcefully, and immediately, stop a container

docker kill <container-id>

run a command in a running contianer (optionally interactive)

docker exec [-it] <container-id> <command>

Exiting an interactive session can usually be accomplished cmd+c will exit, if not try ctrl+d, or simply type exit
Dockerfile


FROM : specifty a base image to start from
LABEL : add arbitrary labels, such as author with author=<you-name>
WORKDIR : specify a working directory in the container (all commands after, use this as root)
COPY : copy somePath into the container working directory
RUN : run arbitrary commands
CMD : set an initial start command for when your container builds

Here is an example Dockerfile
# use a base image
FROM alpine

# dl and install deps
RUN apk add --update redis

# tell it what to do when it starts
CMD ["redis-server"]
this is a very basic container,  here's another, thats slightly more complete:
FROM node:alpine
LABEL author="my-docker-id"

WORKDIR /usr/app

COPY ./package.json ./
RUN npm install
COPY ./ ./

CMD ['npm', 'start']
as each instruction is cached, the order is important, to avoid unneccessary rebuild steps and cache busting.
Building containers

after creating your Dockerfile run the following in your project dir:

docker build -t <username/name> .

not that this will name your build with the <username/name> . . then run the following to start that container, notice we're parsing in the -p flag to specify the port, and are able to run the container by name, rather than id.

docker run -p <external-port>:<container-port> <container-id or name>