2022-04-20 Dockers Useful commands

Installing docker on ubuntu (NEVER use SNAP version, it has lots of problems with dockers)

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sudo apt install docker.io

Docker must work without sudo

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sudo chmod a+wrx /var/run/docker.sock

Connect to docker bash

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docker exec -it asya_backend bash

Copy files into docker

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docker cp foo.txt container_id:/foo.txt
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docker cp ./logs.bag ros-apple-silicon_ros_1:/logs.bag

Run docker mounting local file system folder and TCP port forwarding

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docker run --privileged -it -v /local/ui_2022_Q1:/remote/ui_2022_Q1 -p 6080:80 --shm-size=512m alarm-container:latest

Docker build from Dockerfile in root dir

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docker build --no-cache --platform=linux/amd64 -t tag_name .

Docker see logs in CMD (-f follow)

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docker container logs -f asya_backend

Docker list images

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docker image ls

Docker list containers

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 docker container ls -a 

Docker start container

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docker start container_id

Docker create container from image

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docker run myimage

Docker lkill container

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docker kill container_id

Docker remove images

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docker image rm image_name

Docker remove container

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docker rm <container_id_or_name>

Docker save image

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docker save -o ./dockers/env.tar env

Docker load

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docker load < myimage.tar

Dockerfile

RUN - shell commands executed in sequence, better to combine as many as possible to have option to cache data

COPY - coppies files and directories to target image, executed in sequence, ⚠️ Very important to use with .dockerignore , because docker will include all files in ./Dockerfile root without it regardless of COPY commands

CMD - startup script shell

there can only be one CMD instruction in a Dockerfile. If more than one CMD instruction is listed, only the last CMD will take effect only single last CMD will be executed in

Cleanup as much as you can in docker image to reduce size

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RUN apt-get clean && \
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    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

Mofiyable parameters

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# we need to specify default values
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ENV ENVIRONMENT=production
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ENV CLUSTER=1
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# there is no need to use parameters array
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CMD node server.js ${CLUSTER} ${ENVIRONMENT}

then wehn running can pass with -e

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$ docker run -d -p 9000:9000 -e ENVIRONMENT=dev -e CLUSTER=0 -me/app

Size and performance

Important to have .dockerignore, othewise will copy ALL files from directory in container

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*
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!Dockerfile
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!controllers/**
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!models/**
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!denoiser/**
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!modules/**
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!keys/**
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!modules_core/**
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!modules_ext/**
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!./*.py
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!./*.sh
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!./*.json
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!./*.yaml

Sometimes can use docker-slim to reduce size of already built docker images

Building from Dockerfile

Dockerfile in root directory, then build using

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docker build -t docker_image_name .

On MacOS ARM can also build Linux x64 dockers

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docker build --platform=linux/amd64 -t docker_image_name .

Discard cached scripts

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docker build --no-cache -t docker_image_name .

Docker control

Start, restart, stop, status

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sudo systemctl start docker
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sudo systemctl restart docker
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sudo systemctl stop docker
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sudo systemctl status docker

Other

Docker for using ROS under MacOS 2023-03-28

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docker pull tiryoh/ros-desktop-vnc
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docker run -p 6080:80 --shm-size=512m tiryoh/ros-desktop-vnc:melodic