DevOps Classroom notes 03/Dec/2025

Install docker

Lab setup on AWS

• Create a ubuntu server in AWS (t3.micro)
• Ensure ssh keys are setup
• Create a security group in AWS with all ports opened.
• Note: Watch classroom recording for creating server

Docker installation on Linux

• we have two ways of installing docker
  • a script
  • commands

Command based installation

• Refer Here for official installation docs
• Run the following commands

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

# Add the repository to Apt sources:
sudo tee /etc/apt/sources.list.d/docker.sources <<EOF
Types: deb
URIs: https://download.docker.com/linux/ubuntu
Suites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")
Components: stable
Signed-By: /etc/apt/keyrings/docker.asc
EOF

sudo apt update
sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y

• docker installation will create a group called as docker. All the users who are part of this group can communicate with docker daemon.
• Lets add a current user (ubuntu) to the docker group

sudo usermod -aG docker ubuntu

Script based installation

• This works on all popular distributions

curl -fsSL https://get.docker.com -o /tmp/install-docker.sh
sh /tmp/install-docker.sh

• Add the user to the docker group, logout and login

What is happening inside container

Examine Linux Host

• Command: docker run -d --name inspect1 alpine sleep 1d
• Processes
  
• Disks
  
• CPU, memory and running processes
  
• Network
  

Examine inside a container

• Let me run a alpine image

docker run -d --name inspect1 alpine sleep 1d

• Let me execute interactive commands inside container

docker exec -it inspect1 /bin/sh

• Disks
  
• process
  
• network
  
• cpu, memory
  
• Conclude: Each container gets
  • its own disk contents (from image)
  • its own network and network interface
  • its own cpu and ram
  • its own process tree
• Exercise:
  • Install docker on ubuntu in AWS
  • try the same experiment with
    • ubuntu:24.04 image
    • fedora:42 image