Installation

**Notice: An easier method is now available through a Dockerized version of MegaMek!

These are basic instructions for getting a dedicated server up and running using a hosting provider. Does NOT require adjusting your own router or firewall settings. These are at a basic to intermediate level. Familiarity with SSH and the shell are imperative! Do NOT use a web based console for this tutorial.

I’ll be using DigitalOcean as a basis for this. They have a large collection of tutorials on setting up a server. They can be used with other providers as well.

For this tutorial, we’ll be using their cheapest droplet to setup an instance on which is $5/mo USD as of this writing. This will allow us to dedicate 768M of ram to MegaMek which should be more than enough for most games and scenarios. If you need more, upgrading to the $10/mo USD instance is a few clicks and the settings can be adjusted to give MegaMek 1536M of ram instead. In our testing, that was overkill.

If increasing the ram, adjust the start up script and replace the two instances of 768 with the amount of memory you want to allocate. Remember to leave at least 256M available for the system to function.

To setup an account at DigitalOcean, you can go directly there or use this referral link. Both will get you $200 USD credit for first 60 days (as of 4/20/23), the referral will credit me (TapEnvy.us, LLC) $25 USD AFTER you’ve spent $25.

If using DigitalOcean, the initial survey can be a bit daunting. Most is for their internal CRM to help them figure out how people are using their services. We’ve suggested people fill in self hosted game server in for What is the project? (or however it’s phrased).

If unfamiliar with initial server setup, please check out Initial Server Setup with Ubuntu 24.04 for setting up the initial user that we’ll be using for MegaMek.

After you’ve done the initial server setup, follow along using the created user.

We suggest calling the user megamek to keep it all the same as below. If you choose a different username, you’ll need to make adjustments to the startup script replacing the user with what you chose as well as the megamek portion of the working directory.

  • Ubuntu 24.04 LTS
  • OpenJDK 17 LTS
  • 1 vCPU
  • 1GB RAM
  • 25G HDD

Before you begin

Make sure you have a non-privileged user created with sudo privileges and you can login as said user. You do NOT want to run MegaMek as the root user for security reasons. If not user how to do this, follow this tutorial - Initial Server Setup with Ubuntu 24.04.

System Updates and Java

Before we even begin to get MegaMek setup, we need to make sure the server is up to date with all of it’s patches and OpenJDK is installed. It’s best to log in via the created user vs root for security reasons.

First update all the software with the following command. It’s all in one line to chain 3 commands together.

# step 1
sudo apt update && sudo apt upgrade -y && sudo apt dist-upgrade -y

This will update the software list, upgrade already installed packages, and upgrade the kernel if needed. A reboot is recommended after this but can wait until after everything else has been setup.

For OpenJDK, it’s another quick command:

# step 2
sudo apt install openjdk-17-jdk-headless

This will install OpenJDK 11 for headless systems. This basically means for systems without a monitor attached.

If using the UFW firewall as mentioned in the above tutorial, it is important that you open up the port for MegaMek to use otherwise you wont be able to connect to the running server later.

# step 3
sudo ufw allow 2346

Getting MegaMek

Since we don’t have a GUI to click to download, we need to get a copy of the archive directly from the MegaMek website. Navigate there in your favorite browser and copy the Linux URL from the downloads page. You can choose either the MekHQ package OR the MegaMek one. Both will have the same files for a dedicated server. We recommend using the MekHQ package to avoid seeing the client/server hash mismatch error in the logs. So long as the VERSION (ie: 0.49.19.1) matches on both, there should be no issues.

To get it onto the server, we’re going to use wget to have it download the package.

# step 4
wget <URL of package>

From a fresh login, this will download it into your home directory. Once downloaded, we need to decompress the archive.

tip If unable to determine the filename, you can get the current listing with:

ls -lha

This will return a listing of files and folders in the current directory.

For MekHQ 0.49.19.1:

# step 5
tar -zxf mekhq-0.49.19.1.tar.gz

To better understand what’s going on, we are telling the tar command to

  1. (z) decompress the compressed file,
  2. (x) extract all files from the archive,
  3. (v) do it verbosely so you can see the output, and
  4. (f) which file to extract from.

Setting up for auto start on reboot

Now that we have MegaMek download and ready to go, we need to get it setup to start on system start. What we are about to do is

  1. Create a symlink to a stable folder name so we don’t have to touch system files on each update.
  2. Create the start up script to load MegaMek
  3. Tell the system about the file.
  4. Enable it for startup

First the symlink. This is so that when you update to a newer version, you can stop the running instance, remove the old link, make a new one, and start it up again without having to run any privileged commands or tell the system something has changed. It’ll just work.

Again, using MekHQ 0.49.19.1:

# step 6
ln -s mekhq-0.49.19.1 stable

This will create a link from the extracted location to a folder named stable which we will use in our start up script.

For the startup script, we need to create what is known as a systemd service file. This is how Ubuntu will know about MegaMek and to start it at system startup.

# step 7
sudo nano /etc/systemd/system/megamek.service

Enter your password when prompted. This will open up the about to be created megamek.service file in a place that SystemD will see it using the nano test editor. Copy and paste below into the window, Control+X to save and Enter until back to terminal:

[Unit]
# step 8
# 1
Description=MegaMek Dedicated Server

# 2
After=network.target

[Service]
# 3
Type=simple

# 4
User=megamek

# 5
WorkingDirectory=/home/megamek/stable

# 6
ExecStart=/usr/bin/java -Xms768m -Xmx768m -jar MegaMek.jar -dedicated -port 2346

# 7
Restart=always

[Install]
# 8
WantedBy=multi-user.target

What this does is:

  1. gives it a name,
  2. tells it to start after the network has started,
  3. that it’s a simple service (it really is),
  4. run it as the megamek user,
  5. inside the stable directory we linked above.
  6. It’ll run the instance using 768M of RAM on port 2346.
  7. To always restart when it crashed, and
  8. that it’s to be setup for a default system state.

Now that we’ve added a systemD file, we need to let it know it’s there.

# step 9
sudo systemctl daemon-reload

This will tell SystemD to reload all of the service files and check for changes.

To confirm it caught the new file…

# step 10
sudo systemctl status megamek.service

and you should see something similar to

● megamek.service - MegaMek Dedicated Server
     Loaded: loaded (/etc/systemd/system/megamek.service; disabled; vendor preset: enabled)
     Active: inactive (dead)

That’s a good sign! Now we just need to enable it and start it with…

# step 11
sudo systemctl enable megamek.service
sudo systemctl start megamek.service

Now re-run the status command above and it should look something like…

● megamek.service - MegaMek Dedicated Server
     Loaded: loaded (/etc/systemd/system/megamek.service; enabled; vendor preset: enabled)
     Active: active (running) since Sun 2020-07-05 17:51:35 UTC; 5s ago
   Main PID: 36908 (java)
      Tasks: 16 (limit: 1137)
     Memory: 149.8M
     CGroup: /system.slice/megamek.service
             └─36908 /usr/bin/java -Xms768m -Xmx768m -jar MegaMek.jar -dedicated -port 2346

Jul 05 17:51:35 ghost-bear systemd[1]: Started MegaMek Dedicated Server.
Jul 05 17:51:35 ghost-bear java[36908]: Redirecting output to megameklog.txt

Congratulations! You have your own server setup now using the stock MegaMek package! You can get to it using the IP Address in the control panel using the default port of 2346.

Now, if you haven’t already, you should restart the server to make sure all the patches have applied and that the server will load up on startup.

# step 12
sudo shutdown -r now

This will trigger the shutdown command with the reboot option and to do it now vs scheduling it for later. If using DigitalOcean, in about 1 minute, the server should be back up and running. Log back in and re-run the status command to confirm.

Happy Hunting MekWarrior!