Docker

☝️

Use Ask AI feature on the official docs.

What and Why?

Abbreviate

This list isn’t complete.

ps = process status : check running containers (with a for all)

i = interactive : used in docker exec or docker run

t = terminal : used in docker exec or docker run

m = memory

v or -volume : corresponding folders in/out containers.

-rm : create temprarily a container (removed after exit)

Installation

Official docs.

Other notes: Docker & GPU, WSL on Windows.

Client: OrbStack, official apps.

☝️

OrbStack supports containerName.orb.local, which points to the local server. It also supports logs, debugging, and opening a terminal inside the container.

Docker Hub Container Image Library | App Containerization

References

Play with Docker – right on the web.

Yury Pitsishin – Docker RUN vs CMD vs ENTRYPOINT.

What is the difference between devel and runtime tag for a Docker container? - Stack Overflow

FastAPI in Containers - Docker - FastAPI (Provides clear, step-by-step explanations for building FastAPI Dockerfiles)

General

1# docker's version
2docker --version

1# RAM & CPU usages
2docker stats
3docker stats <container_name>

1# Remove any resources
2docker system prune

Images

1# Build image with Dockerfile
2docker buildx build -t v2daimg .
3# docker build -t <img_name> .
4# image name must be in lowercase
5# run again to update the build
6
7# Set target platform for build
8docker buildx build -t v2daimg --platform=linux/amd64 .
9
10# To know the host platform within a running container
11docker run --rm <image_name> uname -m
12# eg: aarch64
13
14# don't use the cached layer from previous build
15docker build --no-cache -t img_name .
16
17# Custom Dockerfile.abc
18docker build -t <img_name> . -f Dockerfile.abc

More about --platform

1# Create an image from current container
2docker ps -a # Check all containers
3docker commit <container_id> <new_image_name>

1# list images on the host
2docker images
3
4# list all
5docker images -a

1# Where are images stored?
2docker info
3# normally, /var/lib/docker/

1# Rename an image
2docker image tag old:latest myname/new:latest

1# Remove a specific image
2docker image rm <IMAGE_ID>

1# Remove all unused images
2docker system prune -a

Dangling images are layers that have no relationship to any tagged images.

1# list dangling images
2docker images -f dangling=true

1# remove dangling images
2docker images purge

If you use docker images -a and see a lot of <none>:<none> images. Don’t be worry to fast, if they’re dangling images, they take spaces, otherwise, they’re harmless to your drive! Check this SO question.

Containers

☝️

In Obstack, check Logs tab to see the logs inside a container! For example, when a container fails to start.

Creating a new container,

1# Quickly create a testing container from an image
2docker create --name container_test -t -i imageId bash
3docker start container_test
4docker exec -it container_test bash

1docker run --name <container_name> -dp 3000:3000 -v todo-db:/etc/todos imageId

-d = --detach (run in background), -p = --publish (map ports). 3000 (left) is the host port, 3000 (right) is the container host. -it to enable interactive mode (then use ctrl+p, ctrl+q to detach from running container). Without -it, ctrl+p, ctrl+q may not work!

1# run a container with docker-compose
2docker compose up
3# legacy: docker-compose up
4
5# with custom docker-compose file
6docker compose -f compose.admin.yaml up -d
7# docker-compose -f docker-compose.admin.yml up -d

-d = detach. -it not availbale for docker compose!

1# If you run 2 container in the same folder name
2docker compose -p "project_1" up -d
3docker compose -p "project_2" up -d
4# docker-compose -p "project_1" up -d
5# docker-compose -p "project_2" up -d

1# Run a command in a running docker without entering to that container
2# e.g. running "/usr/sbin/sshd -Ddp 22"
3docker exec -it -d docker_thi_dc /usr/sbin/sshd -Ddp 22

-d = Detached mode

1# want docker auto removes a container after exit
2docker run --rm ...

Working with created containers,

☝️

OrbStack supports containerName.orb.local, which points to the local server. It also supports logs, debugging, and opening a terminal inside the container.

1# list running containers
2docker ps
3docker ps -a # all (including stopped)

1# only the ids
2docker ps -q
3docker ps -a -q

1# container's size
2docker ps -s
3docker ps -a -s

1# container's names only
2docker ps --format '{{.Names}}'
3docker ps -a --format '{{.Names}}'

☝️

We can use sometimes interchangeable between <container_id> and <container_name>.

1# Check the last command in container
2docker ps --format '{{.Command}}' --no-trunc

1# check log
2# useful if we wanna see the last running tasks's
3docker container logs <container_name>

1# get ip address
2docker inspect <container_name> | grep IPAddress

1# Attach to the running container
2docker attach <container_name>

Detach by: ctrl+p then ctrl+q. If it’s not working (iTerms), try ctrl+c.

1# get info (container's id, image's id first)
2docker ps -a

1# start a stopped container
2docker start <container_id>
3
4# start and enter the container
5docker start -i <container>

1# stop a container
2docker stop <container_id>

1# Entering the running container (not attach)
2docker exec -it <container_name> bash

1# stop all running containers
2docker stop $(docker ps -a -q)

1# Attach to the running container
2docker attach <container_name>

ctrl+p then ctrl+q to detach

1# Go inside a container
2docker exec -it containerId /bin/bash

Combine -it for interactive sessions, like running a shell.

Remove a container,

1# remove a specific containers
2docker rm -f <container-id>

1# remove all containers
2docker rm -f $(docker ps -a -q)

Zsh in a container

If you have already a container, enter that container and then,

1# Enter
2docker exec -it container_name bash
3
4# Install zsh
5apt-get update
6apt-get install zsh
7zsh
8
9# Install curl
10apt-get install curl
11
12# Install oh-my-zsh
13sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

If you want to integrate the zsh installation in the Dockerfile,

1RUN apt-get install zsh && apt-get install curl
2RUN PATH="$PATH:/usr/bin/zsh"
3RUN sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

💡

Now, enter the container by docker exec -it zsh (instead of bash)!

Troubleshooting

1# Build image with Dockerfile 2docker buildx build -t v2daimg . 3# docker build -t <img_name> . 4# image name must be in lowercase 5# run again to update the build 6 7# Set target platform for build 8docker buildx build -t v2daimg --platform=linux/amd64 . 9 10# To know the host platform within a running container 11docker run --rm <image_name> uname -m 12# eg: aarch64 13 14# don't use the cached layer from previous build 15docker build --no-cache -t img_name . 16 17# Custom Dockerfile.abc 18docker build -t <img_name> . -f Dockerfile.abc

1# run a container with docker-compose 2docker compose up 3# legacy: docker-compose up 4 5# with custom docker-compose file 6docker compose -f compose.admin.yaml up -d 7# docker-compose -f docker-compose.admin.yml up -d

1# If you run 2 container in the same folder name 2docker compose -p "project_1" up -d 3docker compose -p "project_2" up -d 4# docker-compose -p "project_1" up -d 5# docker-compose -p "project_2" up -d

1# Enter 2docker exec -it container_name bash 3 4# Install zsh 5apt-get update 6apt-get install zsh 7zsh 8 9# Install curl 10apt-get install curl 11 12# Install oh-my-zsh 13sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"