docker.md

Docker

Installing

run in the terminal:

curl -fsSL htpps://get.docker.com/ | sh

It will download the latest version (not recommended for deployment in your server, you should stay on a stable version)

Check the version

docker --version

Hello World

run in the terminal:

docker run hello-world

If it's the first time running the hello-world docker will pull the image from docker hub

after it's ready it should print

Hello from Docker.

Useful commands

• To check the images just run

dock images

• To check running containers run

docker ps

• To check all containers run

docker ps -a

• to run an interactive terminal of a container

docker run -ti yourimagename

• to run the container in the background

docker run -d yourimagename

• choose the version of image

docker run yourimagename:version

• exiting the container

Press ctrl + d or ctrl + c

• exit the container, but keep it running

press ctrl+p+q

• enter in a running container

docker attach containerID

• create container without executing it

docker create imagename

• stopping a container

docker stop containerID

• pausing container

docker pause containerID

• unpausing container

docker unpause containerID

• container stats

docker stats containerID

• container processes

docker top containerID

• container logs

docker logs containerID

• remove container

docker rm containerID

Limiting CPU and MEM

• to check mem info

docker inspect containerID | grep -i mem

memory: 0 means no limit

• limit memory during container creation

docker run -ti --memory 512m --name containerName ImageName

this will create a container with 512 MB of memory limit, with the name containerName, of the image ImageName

• update the memory limit

docker update --memory 1024m containerID

now the container can use up to 1024 MB of the ram

• check cpu info

docker inspect containerID | grep -i cpu

• creating container with limited cpu

docker run -ti --cpu-shares 1024 --name conainerName ImageName

this container will have 1024 shares of processing power, and the processing power will be split accordingly with all shares of all container running

• updating container cpu limit

docker update --cpu-shares 1024m containerID

Volumes

• create a container with external volume

docker run -ti -v /volumeName ImageName command

Dockerfile

• Running a react app inside a container

FROM node

RUN mkdir /usr/src/app

COPY . /usr/src/app

WORKDIR /usr/src/app

ENV PATH /usr/src/app/node_modules/.bin:$PATH

RUN yarn

CMD [ "npm", "start" ]

• build image

docker build -t imageName:version .