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Docker Cheatsheet

This cheatsheet included Dockerfile command to build Docker image and ny command to interact with your Docker container for learning purpose and a notes.

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Dockerfile

FROM

Which base to use for build Docker image, for example you will use Ubuntu 16.04.

FROM ubuntu:16.04

To get the base image you can see hub.docker.com, just click what do you want to use and see the documentation.

LABEL

To adds metadata into your Docker image, like maintainer and description to help organize images by project.

Using multiple line, you can use :

FROM ubuntu:latest

LABEL maintainer="Your Name"
LABEL description="Description of your image"
LABEL com.project.image="Hello Project"
...
...

or span multiple line.

FROM ubuntu:latest

LABEL maintainer="Your Name" \
      description="Description of your image" \
      com.project.image="Hello Project"
...
...

or one-line.

FROM ubuntu:16.04

LABEL maintainer="Your Name" description="Description of your image" com.project.image="Hello Project"
...
...

After build the image you can see some information the LABEL which you set.

docker inspect <IMAGE_ID>

ENV

To set values for define environment variable in the image.

FROM ubuntu:16.04

ENV PATH /usr/local/bin
...
...

or span multiple line.

FROM ubuntu:16.04

ENV VAR1="variable 1" \
    VAR2="variable 2"
...
...

You can use ENV in RUN functions.

FROM ubuntu:16.04

ENV NGINXPPA="ppa:nginx/stable"

...
RUN add-apt-repository -y $NGINXPPA
...
...

RUN

For executing commmand in container when build the image. For multiple line:

FROM ubuntu:16.04

...
RUN apt-get update
RUN apt-get upgrade -y
RUN apt-get install -y software-properties-common python-software-properties
...

or span multiple line.

FROM ubuntu:16.04

...
RUN apt-get update && \
    apt-get upgrade -y && \
    apt-get install -y software-properties-common python-software-properties
...

COPY

Instruction to copy local file or directory into the image. This insctruction cannot replace old file with new copied file when build the image, you can use ADD to replace old file with the same name.

FROM ubuntu:16.04

...
COPY files /home/user/
...

And you can set file permission when copied into the image.

FROM ubuntu:16.04

...
COPY --chown=user:group files /home/user/
COPY --chown=user:group files /home/user/
...

ADD

Instruction to copy local file or directory, remote file URLs, and extract the compress file into the image.

FROM ubuntu:16.04

...
ADD files /home/user/
...

And you can set file permission when copied into the image.

FROM ubuntu:16.04

...
ADD --chown=user:group files /home/user/
...

Add file from URLs

FROM ubuntu:16.04

...
ADD https://example.com/file.txt /home/user/
...

Add compress file with extracted it.

FROM ubuntu:16.04

...
ADD https://example.com/compress.tar.gz /opt/
...

Docker Command

Command Description
docker images To list available image in local machine
docker search image Search available the image on DockerHub repositories
docker pull image Pull an image from a registry
docker ps Show all running containers
docker build -t name:tag . Build the image with spesific name and tag
*docker commit new_image* Create new images from an existing images or running images
docker run image Run the container image with any options like -it for interactive mode
docker exec image Run a command inside the running container
docker logs image To display the logs of the image
*docker stop * Stop one or more running containers
docker kill image Kill one or more running containers
docker pause image Pause all process on the spesific containers
docker unpause image Unpause all process on the spesific containers
docker rm Remove one or more images
docker stop $(docker ps -aq) Stop all running containers
docker rmi $(docker images –filter “dangling=true” -q –no-trunc) –force Remove all untagged images
docker rm $(docker ps -aqf status=exited) Remove an exited containers
docker rm $(docker ps -aq) Remove all images

Refrences