Add service unit for single services and fix multi-server unit. Also …

…improve minecraftctl script.

systemd/screen/minecraft/multiple/minecraft@.service

@@ -0,0 +1,37 @@
+[Unit]
+Description=Minecraft Dedicated Server %i
+Wants=network-online.target
+After=syslog.target network.target nss-lookup.target network-online.target
+
+[Service]
+Environment="JAVA_RUNTIME=/usr/bin/java"
+
+WorkingDirectory=/opt/minecraft
+
+User=minecraft
+Group=minecraft
+
+TimeoutStopSec=2m
+
+Restart=on-failure
+RestartSec=1m 30s
+
+Type=forking
+
+# Use optimized java GC flags https://mcflags.emc.gs/ although they are meant for Paper they will do fine with other java server implementations as well
+ExecStart=/usr/bin/screen -dmS minecraft-%i -- $JAVA_RUNTIME -server -Xms2G -Xmx2G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true -jar minecraft_server.jar
+ExecStop=/usr/bin/screen -S minecraft-%i -p 0 -X stuff stop\015
+ExecStop=/bin/bash -c 'while kill -0 $MAINPID >/dev/null 2>&1; do sleep 1; done'
+
+# It is recommended to turn this on for most services (except containerization).
+# Implies MountAPIVFS=yes
+ProtectControlGroups=yes
+
+# /home, /root and /run/user seem to be empty from within the unit. It is recommended to enable this setting for all long-running services (in particular network-facing ones).
+ProtectHome=yes
+
+# Read only mapping of /usr /boot /efi and /etc
+ProtectSystem=full
+
+[Install]
+WantedBy=multi-user.target

systemd/screen/minecraft/multiple/minecraftctl

@@ -0,0 +1,83 @@
+#!/bin/bash
+set -euo pipefail
+IFS=$'\n\t'
+
+PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+SAFE_SELF="/usr/local/bin/minecraftctl"
+
+WORKING_DIRECTORY="/opt/minecraft"
+MINECRAFT_USER="minecraft"
+SYSTEMD_UNIT_NAME="minecraft"
+SCREEN_NAME="test"
+
+print_help() {
+  echo "Usage: $(basename "$0") [console|run|status|start|stop|restart|enable|disable] INSTANCE" >&2
+  echo "    OR $(basename "$0") run INSTANCE COMMAND" >&2
+  echo "    OR $(basename "$0") create NEW_INSTANCE SERVER_JAR" >&2
+}
+
+require_no_arguments() {
+  if [[ $# -ne 0 ]]; then
+    print_help
+  fi
+}
+
+if [[ $# -lt 2 ]]; then
+  print_help
+  exit
+fi
+
+if [[ "$(id -un)" != "$MINECRAFT_USER" ]]; then
+  sudo -n -u "$MINECRAFT_USER" "$SAFE_SELF" "$@"
+  exit
+fi
+
+command=$1
+instance=$2
+shift 2
+
+if [[ ! -d "$WORKING_DIRECTORY/$2" && "$command" != create ]]; then
+  echo "Unknown instance: $instance" >&2
+  exit 2
+fi
+
+case "$command" in
+run)
+  if [[ $# -eq 0 ]]; then
+    echo -n "Command: "
+    IFS= read -er mc_command
+  else
+    OLD_IFS="$IFS"
+    IFS=' '
+    mc_command="$*"
+    IFS="$OLD_IFS"
+  fi
+  script -qc "screen -S '$SCREEN_NAME-$instance' -p 0 -X stuff $(printf '%q' "$mc_command")\015" /dev/null
+  ;;
+console)
+  require_no_arguments "$@"
+  script -qc "screen -x '$SCREEN_NAME-$instance'" /dev/null
+  ;;
+start | stop | restart | status | enable | disable)
+  require_no_arguments "$@"
+  systemctl "$command" "$SYSTEMD_UNIT_NAME@$instance.service"
+  ;;
+create)
+  if [[ $# -ne 1 ]]; then
+    print_help
+    exit 1
+  fi
+  jar_file="$1"
+  jar_file_name="$(basename "$jar_file")"
+  shift
+  mkdir "$WORKING_DIRECTORY/$instance"
+  cp "$jar_file" "$WORKING_DIRECTORY/$instance/$jar_file_name"
+  if [[ "$jar_file_name" != minecraft_server.jar ]]; then
+    ln -s "$jar_file_name" "$WORKING_DIRECTORY/$instance/minecraft_server.jar"
+  fi
+  echo "eula=true" >"$WORKING_DIRECTORY/$instance/eula.txt"
+  ;;
+*)
+  print_help
+  exit 1
+esac

systemd/screen/minecraft/single/minecraft.service

@@ -0,0 +1,37 @@
+[Unit]
+Description=Minecraft Dedicated Server
+Wants=network-online.target
+After=syslog.target network.target nss-lookup.target network-online.target
+
+[Service]
+Environment="JAVA_RUNTIME=/usr/bin/java"
+
+WorkingDirectory=/opt/minecraft
+
+User=minecraft
+Group=minecraft
+
+TimeoutStopSec=2m
+
+Restart=on-failure
+RestartSec=1m 30s
+
+Type=forking
+
+# Use optimized java GC flags https://mcflags.emc.gs/ although they are meant for Paper they will do fine with other java server implementations as well
+ExecStart=/usr/bin/screen -dmS minecraft -- $JAVA_RUNTIME -server -Xms2G -Xmx2G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true -jar minecraft_server.jar
+ExecStop=/usr/bin/screen -S minecraft -p 0 -X stuff stop\015
+ExecStop=/bin/bash -c 'while kill -0 $MAINPID >/dev/null 2>&1; do sleep 1; done'
+
+# It is recommended to turn this on for most services (except containerization).
+# Implies MountAPIVFS=yes
+ProtectControlGroups=yes
+
+# /home, /root and /run/user seem to be empty from within the unit. It is recommended to enable this setting for all long-running services (in particular network-facing ones).
+ProtectHome=yes
+
+# Read only mapping of /usr /boot /efi and /etc
+ProtectSystem=full
+
+[Install]
+WantedBy=multi-user.target

systemd/screen/minecraft/single/minecraftctl

@@ -0,0 +1,61 @@
+#!/bin/bash
+set -euo pipefail
+IFS=$'\n\t'
+
+PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+SAFE_SELF="/usr/local/bin/minecraftctl"
+
+MINECRAFT_USER="minecraft"
+SYSTEMD_UNIT_NAME="minecraft"
+SCREEN_NAME="minecraft"
+
+print_help() {
+  echo "Usage: $(basename "$0") [console|run|status|start|stop|restart|enable|disable]" >&2
+  echo "    OR $(basename "$0") run COMMAND" >&2
+}
+
+require_no_arguments() {
+  if [[ $# -ne 0 ]]; then
+    print_help
+  fi
+}
+
+if [[ $# -eq 0 ]]; then
+  print_help
+  exit
+fi
+
+if [[ "$(id -un)" != "$MINECRAFT_USER" ]]; then
+  sudo -n -u "$MINECRAFT_USER" "$SAFE_SELF" "$@"
+  exit
+fi
+
+command=$1
+shift
+
+case "$command" in
+run)
+  if [[ $# -eq 0 ]]; then
+    echo -n "Command: "
+    IFS= read -er mc_command
+  else
+    OLD_IFS="$IFS"
+    IFS=' '
+    mc_command="$*"
+    IFS="$OLD_IFS"
+  fi
+  script -qc "screen -S '$SCREEN_NAME' -p 0 -X stuff $(printf '%q' "$mc_command")\015" /dev/null
+  ;;
+console)
+  require_no_arguments "$@"
+  script -qc "screen -x '$SCREEN_NAME'" /dev/null
+  ;;
+start | stop | restart | status | enable | disable)
+  require_no_arguments "$@"
+  systemctl "$command" "$SYSTEMD_UNIT_NAME.service"
+  ;;
+*)
+  print_help
+  exit 1
+  ;;
+esac