Host a Minecraft server on a VPS: Java, RAM, ports and a systemd service

To host a Minecraft Java server on a VPS, install the Java version your Minecraft release needs (Java 25 for the 26.x releases, Java 21 for 1.21.x), give the JVM 2–4 GB for a small world, open TCP port 25565, and run the server as its own user under systemd so it survives a crash and a reboot. This guide sets all of that up on Debian or Ubuntu, with the Rocky and Alma equivalents alongside, and ends with backups and a clean shutdown that actually saves the world.

One technical fact shapes the hardware choice: Minecraft’s main game loop — the “tick” that moves mobs, grows crops and runs redstone — is largely single-threaded. A server lags when one core cannot finish a tick in 50 ms, and adding more cores does not help that. Per-core speed matters more than core count, which is why a few fast cores beat many slow ones for a game server.

How much RAM and CPU does a Minecraft server need?

Treat these as starting ranges, not promises — the real figure depends on your view distance, player count and especially plugins and mods, and the only honest number is the one you measure on your own world:

• Small vanilla server, a handful of players: 2–4 GB of RAM and two fast cores is a sensible start.
• Plugins (Paper/Purpur) or a modpack: more, often 6–8 GB and up. Modded servers are the memory-hungry case; a big pack can want far more than a vanilla world of the same player count.
• Leave headroom. Your -Xmx must be smaller than the machine’s RAM — the OS, backups and the JVM’s own off-heap memory all need room. On a 4 GB box, do not hand Java more than about 3 GB.

If ticks fall behind, the server prints Can’t keep up!. That is a CPU or an I/O problem far more often than a RAM one — see VPS high CPU usage for finding which.

How do I install Java and fix java: command not found?

java: command not found simply means no Java runtime is installed yet — a server image never ships one. The version you need depends on your Minecraft version, and that moved recently: current Java Edition releases (the 26.x line) require Java 25, while 1.21.x releases run on Java 21 and older packs may need 17. Minecraft refuses to start on a Java older than it wants, so match them. Check the requirement for your exact version on the official download page, then install a headless runtime — no desktop libraries on a server.

sudo apt update
sudo apt install -y openjdk-25-jre-headless      # for 1.21.x, use openjdk-21-jre-headless
java -version

Debian 12 (bookworm) only packages Java 17, so for a current server install Java 25 from Adoptium’s Temurin repository with a keyring the modern way:

sudo apt install -y curl ca-certificates gpg
sudo install -d -m 0755 /etc/apt/keyrings
curl -fsSL https://packages.adoptium.net/artifactory/api/gpg/key/public \
  | sudo gpg --dearmor -o /etc/apt/keyrings/adoptium.gpg
echo "deb [signed-by=/etc/apt/keyrings/adoptium.gpg] \
https://packages.adoptium.net/artifactory/deb $(. /etc/os-release && echo $VERSION_CODENAME) main" \
  | sudo tee /etc/apt/sources.list.d/adoptium.list
sudo apt update && sudo apt install -y temurin-25-jre
java -version

# Java 25 needs a current 9.x point release — check with:
dnf list --available 'java-*-openjdk-headless'
sudo dnf install -y java-25-openjdk-headless      # for 1.21.x: java-21-openjdk-headless
java -version

If several Java versions are installed, sudo update-alternatives --config java (Debian, Ubuntu) or sudo alternatives --config java (Rocky) selects the default. The systemd unit below calls /usr/bin/java, which follows that default. To pin one version regardless of the default, put its full path in ExecStart instead — ls /usr/lib/jvm lists what is installed.

How do I download and start the server?

1. 1Create a dedicated user

   Never run the server as root. Give it its own unprivileged account and directory:

   sudo useradd --system --create-home --home-dir /opt/minecraft --shell /usr/sbin/nologin minecraft
   sudo -u minecraft mkdir -p /opt/minecraft/server

2. 2Download the server jar

   Take the server.jar URL for your version from the official minecraft.net server download page — it changes every release, so copy the current one rather than hardcoding an old link. Work as the service user so every file it creates belongs to it:

   sudo -u minecraft bash        # a shell as the service user
   cd /opt/minecraft/server
   curl -fsSLo server.jar "https://piston-data.mojang.com/.../server.jar"   # paste the real URL

3. 3Accept the EULA and start once

   The first run writes config files and then stops, because you have not yet agreed to Mojang’s EULA:

   java -Xms1G -Xmx1G -jar server.jar nogui
   # it exits with: "You need to agree to the EULA..."
   sed -i 's/eula=false/eula=true/' eula.txt
   exit

Setting eula=true records that you accept Mojang’s EULA. Now open server.properties as the service user (sudo -u minecraft nano /opt/minecraft/server/server.properties) and enable RCON, which the service will use for a clean shutdown:

enable-rcon=true
rcon.port=25575
rcon.password=choose-a-long-random-string
# optional but recommended for a private server:
white-list=true
enforce-whitelist=true

How do I run it as a systemd service?

A systemd unit keeps the server running after you log out, restarts it if it crashes, and starts it on boot. The key is a shutdown that saves the world first — so instead of letting systemd kill the Java process, have it send the server’s own stop command over RCON, which saves every chunk before exiting.

# Debian 12/13, Ubuntu 24.04 — the rcon package provides rconclt
sudo apt install -y rcon

# Rocky, Alma 9 — not packaged; install the same client from PyPI in a venv
sudo dnf install -y python3.11
sudo python3.11 -m venv /opt/rcon && sudo /opt/rcon/bin/pip install rcon
# then use /opt/rcon/bin/rconclt wherever this guide says /usr/bin/rconclt

sudo install -d -m 0750 -o minecraft -g minecraft /etc/minecraft
sudo tee /etc/minecraft/rcon.conf >/dev/null <<'EOF'
[mc]
host = 127.0.0.1
port = 25575
passwd = the-same-string-as-server.properties
EOF
sudo chown minecraft:minecraft /etc/minecraft/rcon.conf
sudo chmod 600 /etc/minecraft/rcon.conf

[Unit]
Description=Minecraft server
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=minecraft
Group=minecraft
WorkingDirectory=/opt/minecraft/server
# match -Xmx to your plan, leaving headroom for the OS
ExecStart=/usr/bin/java -Xms2G -Xmx3G -jar server.jar nogui
# graceful stop: save and quit, then wait for Java to exit (systemd signals as soon as ExecStop returns)
ExecStop=/bin/sh -c '/usr/bin/rconclt -c /etc/minecraft/rcon.conf mc stop; while kill -0 $MAINPID 2>/dev/null; do sleep 1; done'
# a JVM ended by SIGTERM exits 143; that is a normal stop, not a failure
SuccessExitStatus=143
Restart=on-failure
RestartSec=10
# give the world time to save before systemd gives up
TimeoutStopSec=90

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now minecraft
sudo systemctl status minecraft
# watch the log
sudo journalctl -u minecraft -f
# test that a stop saves the world:
sudo systemctl stop minecraft     # the log must show "Saving worlds" before it exits

Which port does a Minecraft server need?

Java Edition listens on TCP 25565. Open exactly that, and no more:

# ufw (Debian, Ubuntu)
sudo ufw allow 25565/tcp comment 'Minecraft'

# firewalld (Rocky, Alma)
sudo firewall-cmd --permanent --add-port=25565/tcp && sudo firewall-cmd --reload

Leave RCON’s port 25575 closed. The vanilla server binds RCON to every interface unless server-ip is set, so the firewall is what keeps it private — with a default-deny firewall it stays closed as long as you never allow it, and the service reaches it over 127.0.0.1. A full firewall walkthrough, including allowing SSH before you enable the firewall, is in the UFW setup guide. Bedrock Edition is a different server program and listens on UDP 19132; this guide is Java Edition.

How do I back up the world safely?

Back up the world directory on a schedule. Because the server writes to it constantly, flush and pause saves over RCON first, copy, then re-enable — so the archive is consistent:

#!/bin/bash
set -euo pipefail
R="/usr/bin/rconclt -c /etc/minecraft/rcon.conf mc"
DEST=/opt/minecraft/backups
mkdir -p "$DEST"
$R save-off                  # stop writing to disk
trap '$R save-on' EXIT       # always resume saving, even if tar fails
$R save-all flush            # flush everything to disk now
tar -czf "$DEST/world-$(date +%F-%H%M).tar.gz" -C /opt/minecraft/server world
# keep the last 14 archives
ls -1t "$DEST"/world-*.tar.gz | tail -n +15 | xargs -r rm --

sudo chown minecraft:minecraft /opt/minecraft/backup.sh
sudo chmod 750 /opt/minecraft/backup.sh
# append to the user's crontab instead of replacing it
(sudo crontab -u minecraft -l 2>/dev/null; echo "30 4 * * * /opt/minecraft/backup.sh") \
  | sudo crontab -u minecraft -

A file backup protects you from a corrupt world or a bad command, but it lives on the same disk — copy the archives off the server too (rsync to another machine is enough). Before a big change, such as a Minecraft update or a new plugin set, a snapshot of the whole VPS from your provider’s panel, if it offers one, is the faster roll-back.

Why does the server lag or crash?

• Steady lag / “Can’t keep up”: a tick is taking too long. Lower view and simulation distance, thin out entities and redstone, and if the box is pinned, work through VPS high CPU usage.
• The process just says Killed: the machine ran out of memory and the kernel killed Java. Lower -Xmx, add RAM, or see why Linux kills your process.
• Crashes on start after an update: almost always a Java-version mismatch — the new Minecraft wants a newer Java than you have installed. Re-check the Java section.

Does a Minecraft server need DDoS protection?

For a public server, yes. Game servers draw denial-of-service attacks, often from whoever just lost, and a small VPS cannot filter a flood on its own — that has to happen upstream, at the provider. Check that your host includes it; on VMHeaven, for example, always-on DDoS mitigation sits in front of every server at no extra cost. What you still do yourself is the ordinary hardening — key-only SSH and the rest of the base setup — so the box that runs the game is not itself the soft target.

What hardware does a Minecraft VPS need?

Because the tick is largely single-threaded, choose fast cores over many cores, and enough RAM for the -Xmx you planned plus headroom. Two to four strong vCores cover a small server; extra cores mainly help world generation, plugins that work asynchronously and everything else on the box. Our Hi-CPU KVM line (AMD EPYC 7443) is built for this kind of one-or-two-thread work. Location matters less than people expect: put the server close to most of your players, and see Frankfurt or Amsterdam for how to measure the route from your own players rather than guess.

A plain VPS is more work than a one-click Minecraft hosting panel, and that is the honest trade: the panel is easier, while a VPS gives you full root, any Java version, any plugin loader, and a box you can use for anything else too. If you are comfortable on the command line, the setup above is a one-time half hour.

Running a different game? The gaming VPS page covers Palworld, Valheim, Enshrouded, Satisfactory, Rust, 7 Days to Die, Project Zomboid, FiveM and ARK: Survival Ascended: what each developer publishes for its server, where it publishes anything, next to the smallest plan on each line with room to start, and a link to each game’s own guide once it is out.

Frequently asked