drkostas / ondemandminecraft

An AWS hosted Minecraft server that will only run when players are active. Players can start the server through a simple UI accessed through free Heroku server hosting.

On Demand Minecraft Server

Using a Python Flask application and AWS, this repository launches an AWS EC2 Instance to host a Minecraft server upon request from users through the web application. The server will automatically shut down after the server has crashed or is empty for 15 minutes. This makes server hosting for small communities very inexpensive. For up to 20 players you can expect $0.02 per hour the server runs. The largest benefit of this system is that the server bill diminishes if your community decides to take a break from the game, and will be ready to pick back up when you want to play again. No subscriptions are required.

Note that this configuration will likely require familiarity with programming, SSH, and the command line.

AWS Setup

This step will properly configure your AWS account and ec2_conf.yml so that an instance can be created via the server.py script (using the flag -r create_instance).

1. Create or access an AWS Account. Under the User Dropdown in the Toolbar, select Security Credentials, then Access Keys, and finally Create New Access Key. Download this file, open it, and copy the values of AWSAccessKeyId and AWSSecretKey to access_key and secret_key in the ec2_conf.yml file.

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere # Modify this
         secret_key: YourAWSSecretKeyHere # Modify this
   ............................................................

2. Navigate to the EC2 Dashboard under the Services Dropdown and select Security Groups in the sidebar. Select Create Security Group, input minecraft for the Security group name. Create Inbound Rules for the following:

   • Type: SSH Protocol: TCP Port Range: 22 Source: Anywhere
   • Type: Custom TCP Rule Protocol: TCP Port Range: 25565 Source: Anywhere
   • Type: Custom UDP Rule Protocol: UDP Port Range: 25565 Source: Anywhere

   In ec2_conf.yml, set ec2_secgroups to the name of the security group.

   aws:
    - config:
        access_key: YourAWSAccessKeyIdHere
        secret_key: YourAWSSecretKeyHere
        ec2_secgroups:
          - YourGroupNameHere # Modify this
   ............................................................

3. Under the EC2 Dashboard navigate to Key Pairs in the sidebar. Select Create Key Pair, provide a name and create. Move the file that is downloaded into the ./keys directory in the project. In ec2_conf.yml, set ec2_keypair to the name entered, and ssh_key_file_name to the name.pem of the file downloaded.

   THIS MIGHT BE SUBJECT TO CHANGE

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName # Modify this
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem # Modify this
   ............................................................

   You have also the option to upload the key to Dropbox in order to keep it hidden from the repo. See the Dropbox Setup section.

4. This step is concerned with creating the AWS instance. View https://docs.aws.amazon.com/general/latest/gr/rande.html (Or google AWS Regions), and copy the Region column for the Region Name of where you wish to host your server. In ec2_conf.yml, set the ec2_region variable to the copied value.

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName
         ec2_region: Your-Region-Here # Modify this
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem
   ............................................................

5. Navigate to https://aws.amazon.com/ec2/instance-types/ and select one of the T3 types (with the memory and CPU you desire, I recommend 10 players/GB). Copy the value in the Model column. I've configured mine to use t3.small. In ec2_conf.yml, set the ec2_instancetype variable to the copied value.

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName
         ec2_region: Your-Region-Here
         ec2_instancetype: t3.yourSizeHere # Modify this
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem
   ............................................................

6. Then we must select an image for the instance to boot. Navigate to https://cloud-images.ubuntu.com/locator/ec2/, in the filter at the bottom of the screen, select your region of choice under Zone, pick any LTS (Latest Stable) under Version, under Arch select amd64, and hvm:ebs under Instance Type. Select one of the images available and copy the AMI-ID. In ec2_conf.yml, set the ec2_amis variable to the copied value.

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName
         ec2_region: Your-Region-Here
         ec2_instancetype: t3.yourSizeHere
         ec2_amis:
           - ami-YourImageIdHere # Modify this
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem
   ............................................................

7. At this point you should have the necessary configuration to create a new instance through the server.py script (using the flag -r create_instance flag) in the root folder. Open a command line in the root directory of the project, and execute:

   pip install -r requirements.txt

   After successful installation of dependencies execute:

   python server.py -r create_instance -c configs/ec2_conf.yml

   Copy the Instance ID that is output into the terminal. In ec2_conf.yml, set the instance_id variable to the copied value.

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         instance_id: i-yourInstanceIdHere # Modify this
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName
         ec2_region: Your-Region-Here
         ec2_instancetype: t3.yourSizeHere
         ec2_amis:
           - ami-YourImageIdHere
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem
   ............................................................

Web Application Deployment

In this step the project will get deployed to Heroku's free hosting. This part of the application provides a rudimentary UI and Web URL for users to start the server.

Before deployment it will be important to set the password for the server to start. In ec2_conf.yml, set the server_password variable to the password of your choosing.

aws:
  - config:
      access_key: YourAWSAccessKeyIdHere
      secret_key: YourAWSSecretKeyHere
      instance_id: i-yourInstanceIdHere
      ec2_secgroups:
        - YourGroupNameHere
      ec2_keypair: YourKeyPairName
      ec2_region: Your-Region-Here
      ec2_instancetype: t3.yourSizeHere
      ec2_amis:
        - ami-YourImageIdHere
mineserver:
  - config:
      ssh_key_file_path: ./keys/YourKeyFileName.pem
web_client:
  - config:
      server_password: YourPasswordHere # Modify this
............................................................

1. Set the name of the configuration you will be using at the line 18 in server.py like this: CONFIG_NAME = 'ec2_conf_with_os_vars.yml'
2. Create or have access to a Heroku account.
3. Install and setup the Heroku CLI onto your computer. https://devcenter.heroku.com/articles/heroku-cli#download-and-install
4. In the command line for the directory of this project, type: heroku create YourProjectNameHere
5. Once this new project has been created, it is time to push the project to Heroku. git push heroku master
6. Optional: Use Environmental Variables
   • If you don't want your passwords and keys to be exposed in the configuration .yml file or there is a configuration variable that you don't want to commit to change it each time, you have the option to use environmental variables instead.
   • To do so, change any value you want to obscure in the ec2_conf.yml file like this:
   • e.g. change this: secret_key: YourAWSSecretKeyHere to this: secret_key: !ENV ${SECRET_KEY}
   • where SECRET_KEY is the name of the environmental variable
   • To set the environmental variables in Heroku refer to this guide.
7. The URL to your hosted site should be: YourProjectNameHere.herokuapp.com
8. Access your site and launch/access your server!

Dropbox Setup (Optional)

In this step, you have the option to use Dropbox in order to upload your ssh key file there for it to be hidden from the Github repo and at the same time available for download from Heroku when needed. You can skip this step if you you want to use a private repository.

1. Setup a Dropbox account if you haven't already.
2. Create an Api Key for your Dropbox account.
3. Add the cloudstore section in the ec2_conf.yml file:

   aws:
     - config:
         access_key: YourAWSAccessKeyIdHere
         secret_key: YourAWSSecretKeyHere
         instance_id: i-yourInstanceIdHere
         ec2_secgroups:
           - YourGroupNameHere
         ec2_keypair: YourKeyPairName
         ec2_region: Your-Region-Here
         ec2_instancetype: t3.yourSizeHere
         ec2_amis:
           - ami-YourImageIdHere
   mineserver:
     - config:
         ssh_key_file_path: ./keys/YourKeyFileName.pem
   web_client:
     - config:
         server_password: YourPasswordHere # Modify this
   cloudstore:
     - config:
         api_key: !ENV ${DROPBOX_API_KEY} # Modify this
         remote_folder: OnDemandMinecraft # Modify this
   ............................................................

4. Set an os variable for the Dropbox api key (as described in the 5th step of the previous section) and modify the corresponding section in the ec2_conf.yml file.
5. Do the same for the remote_folder which represents tha name of the Dropbox in which the ssh key file will be stored.
6. Lastly, after placing the ssh key file in the keys folder, upload the file by executing: python server.py -c configs/>.yml -r upload_key_file

AWS Instance Configuration

This step will configure the AWS Linux server to run the minecraft server. It will include SSH connecting to the server, gaining admin privileges, installing java, directory setup, moving shell scripts onto the server, and making a CRON job for these shell scripts. Note that this step will include both an SSH client and a File Transfer client (such as FileZilla) on your PC.

1. The first step will be to get SSH into the server instance. Using the key downloaded from AWS in the section above, add this key to PuTTY or simply access it through command line. The IP address can be obtained by entering the server password on the site, or through the EC2 Dashboard, selecting the iPV4 address from the corresponding instanceID in your configuration file. For MacOS and Linux systems

   ssh -i pathToYourKeyFileHere ubuntu@IPAddress

2. Make the ubuntu user admin if it isn't already with:

   adduser ubuntu sudo

3. The next step will be to install JavaJDK onto your system. For newer versions you may enter: sudo apt install openjdk-11-jdk-headless If this doesn't work you can use sudo apt list and search through these packages for an alternative java version.

4. Open up an FTP client such as FileZilla and connect to the same address as the same user with the same IP address. Drag all files from the instanceSetup folder from this repository, into the root directory of the current user (probably ubuntu, for the purposes of these commands I will be using ubuntu, but feel free to replace with your own user if appropriate).

5. Download the desired Minecraft server version from https://www.minecraft.net/en-us/download/server/, rename it server.jar and drag it into the root directory of the user using FileZilla.

6. Using the FTP client, create a new folder in the root directory of the current user called screens
   OR
   In the SSH client, create a folder in the current directory with the command: sudo mkdir screens

7. Then execute the following command: sudo chmod 700 /home/ubuntu

8. Then execute the next command: export SCREENDIR=/home/ubuntu/screens

9. Then execute the command: sudo crontab /home/ubuntu/crontab -u ubuntu

   Feel free to close the server through the AWS console or execute the command: sudo /sbin/shutdown -P +1

At this point you may restart the server from the Web Application using the password you configured. You should then be able to play!

Additional Remarks

Minecraft Memory Configuration

The server startup command does not specify memory constraints by default, but is available to be specified in ec2_conf.yml. In the event that you configure this from an empty string, the trailing space is required as in the example below. Traditional minecraft server flags apply for this configuration.

aws:
  - config:
      access_key: YourAWSAccessKeyIdHere
      secret_key: YourAWSSecretKeyHere
      instance_id: i-yourInstanceIdHere
      ec2_secgroups:
        - YourGroupNameHere
      ec2_keypair: YourKeyPairName
      ec2_region: Your-Region-Here
      ec2_instancetype: t3.yourSizeHere
      ec2_amis:
        - ami-YourImageIdHere
mineserver:
  - config:
      ssh_key_file_path: ./keys/YourKeyFileName.pem
      memory_allocation: '-Xmx1024M -Xms1024M ' # Modify this
web_client:
  - config:
      server_password: YourPasswordHere
............................................................

UI Configuration

The title and header for the site can be changed in /templates/index.html. Feel free to add any more content or styling to the site, though be careful not to change any form, input, button, or script elements in the template.

Server Maintenance

Maintaining the server is fairly straightforward and is done primarily through FileZilla. Updating the server file can be done by downloading the new server file, renaming it to server.jar and replacing the old file on the server. The world file can be backed up to your PC manually though there is no automated process at this time.