Post

Guide to Docker

Posted
Preview Image
By Ankit Prasad
4 min read
Guide to Docker

Docker

Index

Installing docker

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

# Remove previous installs
for pkg in docker.io docker-doc docker-compose podman-docker containerd runc; do sudo apt-get remove $pkg; done


# Add Docker's official GPG key:
sudo apt-get update
sudo apt-get install ca-certificates curl
sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# Add the repository to Apt sources:
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
sudo apt-get update

# Install docker
sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Pls dont use this

1
2
3
4
5
6
7
8
9
10

## PLS DONT USE THS
# for debian/ubuntu users
sudo apt update
sudo apt install docker.io

# for fedora users
sudo dnf install docker

# for arch users
sudo pacman -S docker

Running docker daemon

1
2

## PLS DONT USE THS
sudo systemctl enable --now docker.service

For adding user to docker group

1

sudo usermod -aG docker $USER

Basic docker commands

  1. HELP 🆘
    1

    docker help
  2. Current running docker processes (containers) 🏃
    1
2

    docker ps
docker ps -a
  • -a –> to get all the running containers
  • -q –> to get just the container id
  1. Stopping and Removing 🛑
    1
2

    docker stop [container_id]
docker rm [docker_id]

1
2

docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

Building and running image

  1. For building docker image 🏗️
    1

    docker build -t [image_name] [dir_of_Dockerfile]
  2. For creating & running docker image 🏃
    1

    docker run --nane [container_name] [image_name]
  • can add -rm for stooping and removing docker as u exit
  • can add -d for detaching it from terminal after running (if ur using default bridge network)
  • add -p [host_port]:[docker_port] for mapping a specific docker port to host port
  1. For executing something inside docker image 🖱️
    1

    docker exec [file/command_wanna_run] [container_name]

Other docker commands

  1. KILL IT 🔪💀
    1

    docker kill [container_id]
  2. Logs 📃
    1

    docker logs [container_id]

Docker hub

  1. Pull
    1

    docker pull [image_name]:[tag]
    • list of docker image
      1

       docker image ls
  2. Tag
    1

    docker tag [image_id] [image_name]:[tag]
  3. Push
    1

    docker push [image_name]:[tag]    # default tag is "latest"

Docker volumes

  1. create
    1

    docker volume create [volume_name]
  2. manage
    1
2

    docker volume list
docker colume inspect [volume_name]
  3. mount
    1
2
3
4

    # for mounting docker volume 
docker run -v [volume_name]:[path_in_container] [docker_image]
# for mounting host directry
docker run -v "[host_directry]":[volume_name] [docker_image]
  4. remove
    1
2

    docker volume rm [volume_name]
docker volume prune   # to remove all unused volumes

Docker Networks

  1. Creating network
    1

    docker network create [network_name]
  2. Connect
    1

    docker network connect [network_name] [container_name]
  3. Disconnect
    1

    docker network disconect [network_name] [container_name]
  4. List & Inspect
    1
2

    docker network ls
docker inspect [network_name]
  5. Delete network
    1
2

    docker network rm [network_name]
doceker network prune    #delete all unused network

Default networks

  1. Bridge networks
  2. Host network
  3. None

Other networks

  1. macvlan
  2. ipvlan
  3. overlay

(There are other possible P&C too….)

Parameters (flags)

  • --subnet 172.76.0.0/16 –> to define subnet
  • --gateway 172.76.0.1/16 –> to define the gateway of the network
  • -o parent=[network_interface] –> to define the physical network interface

Bridge network

It’s the default one no need for any flags.

User-Defined Bridge Network

1
2

docker network create [network_name]
docker run --network [network_name] [container_id] [image_name]

Host network

1

docker run --network host [container_id] [image_name]

None

1

docker run --network none [container_id] [image_name]

Docker Web-Interface

portainer-ce

  1. Instalation

Create a docker voume or direct mount to a host directry

1

docker volume create portainer_data

Run the portainer as a contatiner on the bridge network

1

docker run -d -p 8000:8000 -p 9443:9443 --name portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer-ce:2.21.5

Sample docker-compose

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

---
services:
  portainer:
    image: portainer/portainer:latest
    container_name: portainer
    environment:
      - PUID = ${UID}
      - PGID = ${GID}
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ${DATA}:/data
    ports:
      - 8000:8000
      # - 9000:9000 #HTTP port
      - 9443:9443 #HTTPS port
    restart: always

Dockerfile

Common tags:

  • FROM –> Base image
  • COPY –> Commands to run
  • WORKDIR –> current working dir in the container
  • EXPOSE –> expose the mentioned port
  • CMD –> run the final service (should not have a terminatig shell)

Docker Compose

Common paramaters:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

service
  [service-name]
    image: [image_name]
    container_name: [any_name_for_container]
    hostname: [hostname]
    user: [GID]:[UID]
    # env_file:
    #   - [.env_location]
    environment:
      - [parameter]=[value]
    volumes:
      - [host_location]\:[container_location]
    ports:
      - [host_port]\:[container_port]
    restart: [always, unless-stopped, ....]

Sources

  1. docs.docker.com
  2. dockerlabs.collabnix.com
  3. www.docker.com/blog
  4. docs.portainer.io
Guide, Docker
Docker DevOps Guide Cheat Sheet
This post is licensed under CC BY 4.0 by the author.