Minecraft Server is coming back

UPDATE 20120806 0746 hours:  Since some folks have asked, here’s the init script I’m using to control the minecraft server.  It runs on CentOS (royalty-free rebranding of Red Hat Enterprise Linux):

#!/bin/bash
# /etc/init.d/minecraft
# version 0.3.7 2012-03-06 (YYYY-MM-DD)

### BEGIN INIT INFO
# Provides:   minecraft
# Required-Start: $local_fs $remote_fs
# Required-Stop:  $local_fs $remote_fs
# Should-Start:   $network
# Should-Stop:    $network
# Default-Start:  2 3 4 5
# Default-Stop:   0 1 6
# Short-Description:    Minecraft server
# Description:    Starts the minecraft server
### END INIT INFO

#Settings
SERVICE='minecraft_server.jar'
OPTIONS='nogui'
USERNAME='miner'
WORLD='world'
MCPATH='/opt/minecraft'
BACKUPPATH='/media/archive/minecraft.backup'
CPU_COUNT=1
INVOCATION="java -Xmx1024M -Xms1024M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalPacing -XX:ParallelGCThreads=$CPU_COUNT -XX:+AggressiveOpts -jar $SERVICE $OPTIONS"

ME=`whoami`
as_user() {
  if [ $ME == $USERNAME ] ; then
    bash -c "$1"
  else
    su - $USERNAME -c "$1"
  fi
}

mc_start() {
  if  pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "$SERVICE is already running!"
  else
    echo "Starting $SERVICE..."
    cd $MCPATH
    as_user "cd $MCPATH && screen -dmS minecraft $INVOCATION"
    sleep 7
    if pgrep -u $USERNAME -f $SERVICE > /dev/null
    then
      echo "$SERVICE is now running."
    else
      echo "Error! Could not start $SERVICE!"
    fi
  fi
}

mc_saveoff() {
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "$SERVICE is running... suspending saves"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"say SERVER BACKUP STARTING. Server going readonly...\"\015'"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"save-off\"\015'"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"save-all\"\015'"
    sync
    sleep 10
  else
    echo "$SERVICE is not running. Not suspending saves."
  fi
}

mc_saveon() {
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "$SERVICE is running... re-enabling saves"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"save-on\"\015'"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"say SERVER BACKUP ENDED. Server going read-write...\"\015'"
  else
    echo "$SERVICE is not running. Not resuming saves."
  fi
}

mc_stop() {
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "Stopping $SERVICE"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"say SERVER SHUTTING DOWN IN 10 SECONDS. Saving map...\"\015'"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"save-all\"\015'"
    sleep 10
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"stop\"\015'"
    sleep 7
  else
    echo "$SERVICE was not running."
  fi
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "Error! $SERVICE could not be stopped."
  else
    echo "$SERVICE is stopped."
  fi
}

mc_update() {
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    echo "$SERVICE is running! Will not start update."
  else
    MC_SERVER_URL=http://s3.amazonaws.com/MinecraftDownload/launcher/minecraft_server.jar?v=`date | sed "s/[^a-zA-Z0-9]/_/g"`
    as_user "cd $MCPATH && wget -q -O $MCPATH/minecraft_server.jar.update $MC_SERVER_URL"
    if [ -f $MCPATH/minecraft_server.jar.update ]
    then
      if `diff $MCPATH/$SERVICE $MCPATH/minecraft_server.jar.update >/dev/null`
      then
        echo "You are already running the latest version of $SERVICE."
      else
        as_user "mv $MCPATH/minecraft_server.jar.update $MCPATH/$SERVICE"
        echo "Minecraft successfully updated."
      fi
    else
      echo "Minecraft update could not be downloaded."
    fi
  fi
}

mc_backup() {
   mc_saveoff

   NOW=`date "+%Y-%m-%d_%Hh%M"`
   BACKUP_FILE="$BACKUPPATH/${WORLD}_${NOW}.tar"
   echo "Backing up minecraft world..."
   #as_user "cd $MCPATH && cp -r $WORLD $BACKUPPATH/${WORLD}_`date "+%Y.%m.%d_%H.%M"`"
   as_user "tar -C \"$MCPATH\" -cf \"$BACKUP_FILE\" $WORLD"

   echo "Backing up $SERVICE"
   as_user "tar -C \"$MCPATH\" -rf \"$BACKUP_FILE\" $SERVICE"
   #as_user "cp \"$MCPATH/$SERVICE\" \"$BACKUPPATH/minecraft_server_${NOW}.jar\""

   mc_saveon

   echo "Compressing backup..."
   as_user "gzip -f \"$BACKUP_FILE\""
   echo "Done."
}

mc_command() {
  command="$1";
  if pgrep -u $USERNAME -f $SERVICE > /dev/null
  then
    pre_log_len=`wc -l "$MCPATH/server.log" | awk '{print $1}'`
    echo "$SERVICE is running... executing command"
    as_user "screen -p 0 -S minecraft -X eval 'stuff \"$command\"\015'"
    sleep .1 # assumes that the command will run and print to the log file in less than .1 seconds
    # print output
    tail -n $[`wc -l "$MCPATH/server.log" | awk '{print $1}'`-$pre_log_len] "$MCPATH/server.log"
  fi
}

#Start-Stop here
case "$1" in
  start)
    mc_start
    ;;
  stop)
    mc_stop
    ;;
  restart)
    mc_stop
    mc_start
    ;;
  update)
    mc_stop
    mc_backup
    mc_update
    mc_start
    ;;
  backup)
    mc_backup
    ;;
  status)
    if pgrep -u $USERNAME -f $SERVICE > /dev/null
    then
      echo "$SERVICE is running."
    else
      echo "$SERVICE is not running."
    fi
    ;;
  command)
    if [ $# -gt 1 ]; then
      shift
      mc_command "$*"
    else
      echo "Must specify server command (try 'help'?)"
    fi
    ;;

  *)
  echo "Usage: $0 {start|stop|update|backup|status|restart|command \"server command\"}"
  exit 1
  ;;
esac

exit 0

[[Category:Server]]

And then this is the crontab entry to run the backup every 30 minutes:

0,30 * * * * mount /media/archive && /etc/init.d/minecraft backup; umount /media/archive

UPDATE 20120703 1110 hours:  The server is open for business at IP 67.53.8.172.  I will register a DNS entry shortly.  Currently we have only Bjorn and myself whitelisted.  Post a comment to this page to add your name and tell me who you are.  ATM, only IRL friends are welcome here.

Bjorn wanted to know what I was doing to get the server running.  Here’s a good example of me tweaking the init script the system uses to allocate resources to the minecraft server and make sure it stays running:

Me editing the server’s /etc/init.d/minecraft script

UPDATE 20120703 1021 hours:  Minecraft lives!!!   Still a lot to be done before it’s ready for prime time, though.   Still need inbound routes and firewall rules, and it’s right now running in a temporary instance on the server but it does work:

Screenshot of Minecraft connected to the new server instance on SavageChicken

UPDATE 20120703 0725 hours:  I had to connect a monitor and keyboard.  Turns out it was a BIOS Checksum Failed and I had to hit F1.  After that everything was fine.  It even started the old Minecraft server!  XD  And now Nmap finds it just fine at 192.168.1.105:

SSH to SavageChicken

Aaaand 266 package updates.  XD

UPDATE 20120703 0751 hours: SavageChicken is plugged in and turned on:

The Server Rack (SavageChicken is in the tower case, kitesfear is in the rackmount case.)

But it won’t be as easy as I’d hoped.  The box is connected to the LAN switch but it doesn’t show up on the local subnet:

running nmap from my lappy

For those who don’t grok Linux, Nmap found the router (192.168.1.1), the two interfaces for my lappy (104 and 107), and kitesfear (118).  No SavageChicken.  Sigh.

Okay so the Minecraft server is coming back sometime this week with the latest version of Minecraft.  I still have the server hardware so all I have to do is get it plugged in, get the OS patched and updated, and get Minecraft installed and working.  I’m going to tar up the old Minecraft server installation and deploy a new one with the new version so it’s a fresh start.

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