DevOps Classroom notes 03/Oct/2024

Docker Installation

• For Guided creation of ec2 instance watch classroom recording
• Docker installation
  • Simplest
    bash
curl -fsSL https://get.docker.com -o install-docker.sh
sh install-docker.sh
  • NOw add the current user to docker group
    “`

  </ul>
  <h1>sudo usermod -aG docker $USER</h1>
  sudo usermod -aG docker ubuntu
  “`

• When we install docker the following components will be installed
  • docker ce (docker daemon)
  • docker ce cli (docker client)
  • containerd
  • docker compose
  • docker buildx

---

Docker Package based installation

• Refer Here for ubuntu steps

---

Docker Images

• Docker images have tags which represent versions. If you don’t pass tag, docker will assume it to be latest

docker pull nginx

• Docker images from docker hub
  • official images <application>:<tag>
  • community images organization/application:tag
  • private images <username>/application:tag

---

Docker container creation modes

• Attached/Foreground
  
• Detached
  
• interactive termninal: you want to get into shell while creating container
  

---

Execution in running contianers

• Docker has a command called as exec
  
• We can use exec to run a command inside container
• we can also use exec in an interactive way

docker container exec -it nginx2 /bin/bash

---

Observations:

• Inside containers, the PID 1 is the application startup
• Container will have its own process tree
• Contianer will have its own network, diskmounts, CPU and RAM allocated
• Restrictions can be placed on RAM and CPU
• Inside containers we have its own set of users