solderq35/312-midterm

CS 312 Midterm | Minecraft Server on AWS EC2

312 Midterm Minecraft Server Setup Guide

Table of Contents (Might be broken on PDF)

• Video Demo
• References
• EC2 Setup
• SSH into EC2 Server
• Installing Software Dependencies
  • Install Java 17
  • Install Minecraft Server Jar
• User Permissions
• Running the Minecraft Server
• Automating Server Start
• Minecraft Client

Video Demo

• https://youtu.be/MezIKRTq1zM
  • Read Youtube Video Description for Timestamps

References

• https://www.linkedin.com/pulse/setup-minecraft-server-java-edition-aws-ec2-keran-mckenzie/
  • Heavily inspired by this article although I did have to change the Java install steps due to some dependency errors, and this article also did not cover how to automatically start the server with systemctl
• https://techviewleo.com/install-java-openjdk-on-amazon-linux-system/
  • Helped me a lot on installing Java 17 for the server dependencies
• ChatGPT
  • Helped a lot on the systemctl part for automatically restarting server
• Markdown Table of Contents Generator: https://jsfiddle.net/remarkablemark/o0mja3hf/

EC2 Setup

• From the AWS homepage / dashboard, type in EC2 into the upper left search bar, and click on it to go to the EC2 menu

• From the EC2 menu, click on the Launch Instance button

• In the Launch Instance menu, name your EC2 instance something like "Minecraft" so you can remember it

• For the Application and OS Images (Amazon Machine Image) menu, select an Amazon Linux, 64bit (x86) OS image

  • This should be the default option

• For the Instance type menu, select t2.small (should pick a t2 small or bigger for this)

• For Key pair (login) menu, I recommend just creating a new SSH key (click the Create new key pair button). I used the default options (RSA, .pem)

  • Name the keypair something memorable, like MinecraftKey. In my case though I'm reusing an old key called lab7

• In the Network Settings menu, click the Edit button to the right to edit the Network Settings

  • 
  • Set Auto-assign public IP to Enable, if not already the case
  • Click on "Create Security Group"
  • Keep the existing default SSH option unchanged in the Security Group
  • Click Add security group rule. Set Type as Custom TCP, Protocol as TCP, Port Range as 25565, Source Type as Custom, Source as 0.0.0.0/0, Description as something memorable like Minecraft Port
    • 

• Click Launch Instance button in bottom right to finish EC2 instance setup

SSH into EC2 Server

• Wait a few minutes for the EC2 instance to start up, then return to the EC2 main menu (search EC2 in the upper left search bar)

• Click on Instances link in left navbar

• Click on Instance ID on your Minecraft Server

• Once you are sure it's running (check Instance State status and refresh the page frequently if it hasn't started yet), click the Connect button, then SSH Client

  • 
  • Read instructions on the Connect Menu page
  • Double check with instructions, but run chmod 400 <private SSH key> if on Unix on your PC (If your local PC is Windows, it should work out of the box). Make sure you are in a directory where you can access the SSH private key. Maybe put that private SSH key in your PATH
  • Connect to your instance with the public DNS, e.g. ssh -i "<private key filename>" <public DNS>, where the values in brackets are stand-in values. Go back to the Instances menu for your EC2 instance if you want to double check the public DNS value
    • Example: ssh -i "lab7.pem" ec2-user@ec2-54-175-58-38.compute-1.amazonaws.com
    • 

• Make sure you can SSH into your EC2 instance before proceeding further

Installing Software Dependencies

Install Java 17

Run the following commands after SSH'ing into your EC2 instance:

• wget https://download.java.net/java/GA/jdk17/0d483333a00540d886896bac774ff48b/35/GPL/openjdk-17_linux-x64_bin.tar.gz

  • Install the tar archive for Java 17 (OpenJDK 17)

• tar xvf openjdk-17_linux-x64_bin.tar.gz

  • Extract the archive with tar command

• sudo mv jdk-17 /opt/

  • Move the extracted folder into /opt/

• sudo tee /etc/profile.d/jdk.sh <<EOF
  export JAVA_HOME=/opt/jdk-17
  export PATH=\$PATH:\$JAVA_HOME/bin
  EOF
  

  • Run these commands one line at a time! Sets the PATH for Java

• source /etc/profile.d/jdk.sh

  • Source your profile file

• echo $JAVA_HOME

  • Check where your Java executable is located (should get an output of /opt/jdk-17)

• java -version

  • Double check Java version. Should show an output of something like:

    • openjdk version "17" 2021-09-14
      OpenJDK Runtime Environment (build 17+35-2724)
      OpenJDK 64-Bit Server VM (build 17+35-2724, mixed mode, sharing)
      

Install Minecraft Server Jar

• sudo su

  • Probably a better way of doing this but for now being a sudo user ensures the next parts work as intended

• mkdir /opt/minecraft/

  • Add directories for where the server.jar will go

• mkdir /opt/minecraft/server/

  • Add directories for where the server.jar will go

• cd - Add directories for where the server.jar will go

  • Navigate to the directory where the server.jar will go

• wget https://launcher.mojang.com/v1/objects/c8f83c5655308435b3dcf03c06d9fe8740a77469/server.jar

  • Install the server.jar in the /opt/minecraft/server/ directory

User Permissions

• At this point you should still be signed in as root (due to sudo su)

• cd

  • To return to root directory

• exit

  • To sign out of root user

• whoami

  • To check default (non root) username. It should say ec2-user for the default user. If not, write down what the username for the next steps and substitute accordingly

• sudo chown -R ec2-user:ec2-user /opt/minecraft

  • Give the ec2-user elevated permissions in the opt/minecraft directory

• sudo chmod -R 750 /opt/minecraft

  • chmods this opt/minecraft directory the right Linux file permissions. In this case, 750 gives the user read/write/execute and read/execute to people in your organization.
    • Further reference on 750 permissions: https://chmodcommand.com/chmod-750/

• sudo visudo

  • Edit file - Add this to the bottom of visudo file:
    • ec2-user ALL=(ALL) NOPASSWD: /usr/bin/java -Xmx1024M -Xms1024M -jar /opt/minecraft/server.jar nogui
  • This adds the ec2-user as a sudo user, which might be a security issue, but it was a way to let this user run the Minecraft server
    • More Information on editing visudo / sudoers file: https://www.digitalocean.com/community/tutorials/how-to-edit-the-sudoers-file

Running the Minecraft Server

• Return to the server directory with cd /opt/minecraft/server

• Make sure you are still signed in as ec2-user via whoami

• Run java -Xmx1024M -Xms1024M -jar /opt/minecraft/server.jar nogui to see if the server at least runs

• If it's your first time running the server, after running the server you will get an error relating to EULA.

  • Fix with vi eula.txt, set eula=true

Automating Server Start

• Check if this command works as a standalone before adding to systmctl

  • sudo -u <username> <java executable path> -Xmx1024M -Xms1024M -jar <path to server.jar>/server.jar nogui
  • Example: sudo -u ec2-user /opt/jdk-17/bin/java -Xmx1024M -Xms1024M -jar /opt/minecraft/server/server.jar nogui
  • If in doubt, check whereis java to find Java executable path

• Once you're sure that the command above works, then let's add a sytemd file:

  • sudo nano /etc/systemd/system/minecraft.service

  • Add the following:

    • Description=Minecraft Server
      After=network.target
      
      [Service]
      User=ec2-user
      WorkingDirectory=/opt/minecraft/server
      ExecStart=/opt/jdk-17/bin/java -Xmx1024M -Xms1024M -jar /opt/minecraft/server/server.jar nogui
      Restart=on-failure
      
      [Install]
      WantedBy=multi-user.target
      

• Run the following in root directory as ec2-user:

  • sudo systemctl daemon-reload
  • sudo systemctl start minecraft
  • sudo systemctl enable minecraft

• Reboot the EC2 instance now, ssh back in

• Use sudo journalctl -u minecraft.service --t to check if the server is running, press down arrow keys to scroll all the way down

  • 
  • Check back periodically if you just restarted the EC2 instance
    • Ctrl C to leave the logs, then check sudo journalctl -u minecraft.service --t again
  • Not sure on the details on how it works but --t helps you skip to near the bottom of the output logs

Minecraft Client

• Get Minecraft from https://www.minecraft.net/en-us
  • No need for too much detail here right? I did get the paid version of Minecraft for PC (Java edition) if it matters
• After installing and booting up the Minecraft Launcher, go to Installations menu, then New Installation, then release 1.18.2
  • 
  • This is important because 1.18.2 client is needed based on the server installed (e.g. Java 17) in previous steps. Other versions of Minecraft Client may not be compatible!
  • Create the 1.18.2 installation and launch it
• After launching 1.18.2 Minecraft client, select Multiplayer, then Proceed, then Direct Connection. Enter in the Public IPV4 address as stated on your EC2 instance
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• Have fun on your server. Dig a hole in the ground