for ConoHa VPS Minecraft server on ubuntu

minecraft_verup_to_latest.sh

#!/bin/bash
# Supports Minecraft Java Edition 1.17 version 1.17 and above
# Requirements Java 16
set -eu

apt update
apt install -y jq

readonly MINECRAFT_DIR="/opt/minecraft_server"
readonly BACKUP_DIR_PREFIX="backup"
readonly MINECRAFT_SERVER_SERVICE="/etc/systemd/system/minecraft-server.service"

readonly MINECRAFT_SERVER_LATEST_VER=$( curl https://launchermeta.mojang.com/mc/game/version_manifest.json|jq -r '."latest"."release"' )
readonly MINECRAFT_SERVER_LATEST_MANIFEST_URL=$( curl https://launchermeta.mojang.com/mc/game/version_manifest.json | jq -r ".\"versions\"[] | select (.\"id\"==\"${MINECRAFT_SERVER_LATEST_VER}\") | .\"url\" " )
readonly MINECRAFT_SERVER_LATEST_JAR_URL=$( curl "${MINECRAFT_SERVER_LATEST_MANIFEST_URL}" | jq -r ".\"downloads\".\"server\".\"url\"" )
readonly MINECRAFT_SERVER_CURRENT_INSTALLED_VER=$( ls ${MINECRAFT_DIR}/*.jar | cut -d '/' -f4 | sed -e "s/minecraft_server\.//" -e "s/\.jar//" )

readonly BACKUP_DIR="${MINECRAFT_SERVER_CURRENT_INSTALLED_VER}-$(date --iso-8601='minutes')"

systemctl disable --now  minecraft-server.service

function get_java_xmx_param(){
  for line in $(grep ExecStart ${MINECRAFT_SERVER_SERVICE});do
    if echo "${line}" | grep -q "\-Xmx"; then
      echo "${line}" | tr -d "\-Xmx"
    fi
  done
}

readonly jvm_xmx_param=$(get_java_xmx_param)

groupadd minecraft || true
useradd -g minecraft minecraft || true

apt install -y screen

mkdir -p ${MINECRAFT_DIR}/${BACKUP_DIR_PREFIX}/${BACKUP_DIR}
cp -r ${MINECRAFT_DIR}/[^backup]* ${MINECRAFT_DIR}/${BACKUP_DIR_PREFIX}/${BACKUP_DIR}
mv /etc/systemd/system/minecraft-server.service ${MINECRAFT_DIR}/${BACKUP_DIR_PREFIX}/${BACKUP_DIR}

rm ${MINECRAFT_DIR}/minecraft_server.${MINECRAFT_SERVER_CURRENT_INSTALLED_VER}.jar

wget ${MINECRAFT_SERVER_LATEST_JAR_URL} -O ${MINECRAFT_DIR}/minecraft_server.${MINECRAFT_SERVER_LATEST_VER}.jar
chown -R minecraft:minecraft ${MINECRAFT_DIR}

cat >> ${MINECRAFT_SERVER_SERVICE} <<EOF
[Unit]
Description=Minecraft Server
After=network.target

[Service]
WorkingDirectory=${MINECRAFT_DIR}
User=minecraft
Group=minecraft
ProtectSystem=full
ProtectHome=true

ExecStart=/bin/sh -c '/usr/bin/screen -DmS minecraft /usr/bin/java -server -Xms512M -Xmx${jvm_xmx_param} -XX:+UseG1GC -XX:ParallelGCThreads=2 -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10 -jar ${MINECRAFT_DIR}/minecraft_server.${MINECRAFT_SERVER_LATEST_VER}.jar --forceUpgrade nogui'

ExecReload=/usr/bin/screen -p 0 -S minecraft -X eval 'stuff "reload"\\015'

ExecStop=/usr/bin/screen -p 0 -S minecraft -X eval 'stuff "say SERVER SHUTTING DOWN. Saving map..."\\015'
ExecStop=/usr/bin/screen -p 0 -S minecraft -X eval 'stuff "save-all"\\015'
ExecStop=/usr/bin/screen -p 0 -S minecraft -X eval 'stuff "stop"\\015'
ExecStop=/bin/sleep 5

Restart=on-failure
RestartSec=60s

[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl enable --now minecraft-server.service

echo "Version up finished"