— What do we mean by “Configuring Nodes and installing Apps”?

We need to configure nodes like creating Users and setting permissions, and apps installed that we intend to utilize. 

— How do we configuration a node and install apps?

1. SSH into the node
   • Start a terminal
   • If you are using a private key (e.g. “mykey.pem”)
     • Goto to the directory where our private key file exist (e.g. ~Download)
   • Run command, “ssh -i mykey.pem ubuntu@xx.xx.xx.xx” (replace xx with you IP address like 18.118.139.37). We are using the default User=ubuntu that comes with Ubuntu images
     • If you encounter an exception
       • Run command, “sudo chmod 400 mykey.pem” to grant our User read permissions to the file (Group and Other members have no permissions)
2. Create User(s)
   • Run command, “sudo adduser <our user name>” (e.g. surfrrs)
     • Enter a password for our User
3. Password expiration and rotation
   • Passwords may expire at set intervals so we will need to schedule password updates
   • Setting password not to expire is an option that some may argue is viable for Service Accounts and mitigate lock-out scenarios; albeit, we have backup images to recreate nodes in the latter situation
4. Add our User to the sudo list if they should have root permissions
   • Run command, “sudo vi /etc/sudoers”
     • Add a privilege for our User like “surfrrs ALL=(ALL:ALL) ALL”
   • Save (e.g. :wq!)
5. Configure our User to allow remote access (SSH) to our node
   • Run command, “sudo vi /etc/ssh/ssh_config”
   • Run command, “i”-> “AllowUsers surfrrs” -> “:wq!”
   • Run command, “sudo vi /etc/ssh/ssh_config.d”
   • Run command, “/PermitRootLogin”
   • Goto to “no” for PermitRootLogin Run command, “:cw yes”
   • Run command, “:wq!”
   • Run command, “sudo service ssh reload”
     • Note: SSH to our using Username/password works now like “ssh surfrrs@xx.xx.xx.xx” -> enter password
6. Install Java JDK which is a requirement if we are going to utilize this node as a Jenkins agent
   • Run command, “sudo add-apt-repository ppa:linuxuprising/java”
   • Run command, “sudo apt-get update”
   • Run command, “sudo apt-get install openjdk-11-jdk” (this command will install java 11). FYI: be aware that Java 11 will be deprecated on Sep 30, 2024.

Note: For our example, the minimum requirements were completed. Install additional apps as needed like Docker

1. Run command, “sudo apt install docker.io”
2. Run command, “sudo docker –version” to verify the docker version installed

How-To:

• Generate public/private key pairs