Docker

Tool that creates lightweight environments called containers for app deployment. Docker is great at creating isolated spaces for your applications to run on while also providing them with OS level dependencies. Great for:

• Microservices

Concepts

• Containers
• Kubernetes Pod
• Dockerfile
• Docker Node
• Docker Compose

Installation

Arch

1. sudo pacman -S docker
2. sudo systemctl enable docker.service & sudo systemctl start docker.service
3. sudo systemctl start docker.socket

Debian

1. apt update
2. apt install ca-certificates curl
3. sudo install -m 0755 -d /etc/apt/keyrings
4. sudo curl -fsSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
5. sudo chmod a+r /etc/apt/keyrings/docker.asc

echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/debian \
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

7. sudo apt-get update
8. sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Using Docker

Build Container

docker build -t <tagname> .

-t signifies the tag name. you can name this whatever you want . indicates that the Dockerfile is within this directory. you can change this to be the directory name that has Dockerfile if its not in cwd Use docker images to view all created images.

Buildx Container

sudo pacman -S docker-buildx

docker build -t <tagname> .

Run Container

docker run -d -p 1024:1024 <tagname>

-d run in detached mode so it runs as a daemon process -p signifies what host and what port it is running on running docker ps will show that the image is running nc 127.0.0.1 1024 will connect to the container

docker run -d -p 1024:1024 -t <tagID>

docker run -it --privileged <tagname>

Stop Container

docker container stop <id>

Delete Image

Use docker images to list all images then, docker rmi -f <id>

Open Container In App

1. docker ps and note down the container ID
2. docker exec -it <containerid> <app>
   1. useful to make <app> be /bin/sh or python Alternatively:
3. docker images and note down the container name
4. docker run -it <containername> /bin/sh. Note if you want programs like Vim, you must install it in your docker-file

Practical Use Cases

• Make a Docker Compose file which automates the process of creating gitlab servers
• You can use docker like a linux server where you SSH into