Devops Docs

Cloud Basics

  • We'll use

    • Nexus Artifact Repository
    • Jenkins Build Automation

  • We don't install them locally but on servers.

  • IaaS: Infrastructure as a Service

    • You can manage your own servers and infrastructure or
    • Delegate infrastructure management
    • Move your infrastructure to the cloud
    • Just rent servers
    • Using infrastructure which is set up and managed by someone else is IaaS
    • Providers
      • AWS
      • GCP
      • DigitalOcean
      • Microsoft Azure

Setup Server on DigitalOcean

  • By default, droplet has no firewall rules.
  • Add port 22 for your current IP.
  • Add droplet to firewall rule.

Firewall

SSH into server

ssh -i .ssh/devops-droplet root@134.209.252.56

Install Java on Droplet

apt update
apt install openjdk-8-jre-headless

Deploy and run application artifact on Droplet

  • Java app
    • Build Jar file
    • Copy to remote server
    • Run app on the remote server
./gradlew build
  • In build/libs, we want to copy to jar file to the server.
scp -i ~/.ssh/devops-droplet build/libs/java-react-example.jar root@134.209.252.56:/root
  • After running the app, it starts on 7071. But port 7071 is not open by default
  • Add inbound rule for port 7071

Run in detached mode

java -jar java-react-example.jar &

Checking running processes

ps aux | grep java

Use netstat to check running port

apt install net-tools
netstat -lpnt

Create and configure Linux user on the cloud server

  • Best practice
    • Create separate user for every application
    • Give it only the permission it needs to run that app
    • Don't work with the Root user

Add new user

adduser alfred

Add user to sudo group

usermod -aG sudo alfredasare

Switch user

su - alfredasare
  • $ = Standard Linux User
  • # = Root user

Print working directory

pwd

SSH for new users on server

  • Ssh won't work for new user
  • Switch to new user
  • Create .ssh folder for new user
  • Copy public key from local pc
  • In ssh folder on server
sudo vim .ssh/authorized_keys
  • Copy public key and save
  • Can now ssh with this user
  • We'll create a new user for every app we want to run on the server
  • Don't start or run any apps with root

NB:

  • If user need to run commands with sudo, you can add the user to the sudo group
usermod -aG sudo username