I’ve recently set up a Minecraft server on a Raspberry Pi. There’s lots of information on line describing how to do this, but I still had some problems, in part due to a lot of information on-line being out-of-date, in part due to the fact that running a Minecraft server is right on the limit of what a Pi is capable of, and in part due to the fact that I don’t really know much about Minecraft…
Just to be clear, this is about running a Minecraft SERVER, not the game client. The game client doesn’t work well on the Pi, as it doesn’t have enough memory. There is a special game client for the Pi, the Minecraft Raspberry Pi Edition, which is free, and programmable, but is creative mode only, and has no monsters. That is not what this post is about. You can run a server on the Pi (for free) which you can use from a standard game client (which is not free). That is what this post is about.
It is important to understand that there are lots of different Minecraft servers out there, most of which are Java based, but not all. There are potential advantages to not using the standard vanilla Mojang reference server, as some servers are lighter weight, and hence could potentially run better on the Pi. However, lots of servers “out there” are not compatible with the latest (1.7.x) versions of the game client, so it’s probably best to get the vanilla server up and running first, before exploring other possibilities. Note that I’m assuming a Revision 2 Model B Pi with 512MB RAM. I don’t imagine that you will have a good experience with 256MB RAM. You should use raspi-config to allocate as little RAM as possible to the GPU, and you should overclock the Pi as much as you dare.
The Mojang server is a Java server, so you need a fast JVM installed on the Pi. The OpenJDK JVM is too slow – you need the Oracle JVM. Lot’s of info on the web refers to Oracle’s developer preview of Java 8, but that isn’t necessary now, as Oracle’s Java 7 is now a standard part of Raspbian. So just install that:
sudo apt-get update sudo apt-get install oracle-java7-jdk
Use java -version to make sure it has worked. Then just pull the server jar, stick it into an appropriately named directory, and run the server from that directory with a command like:
java -Xms256M -Xmx384M -jar minecraft_server.1.7.2.jar nogui
The first time you run this it will take an age (possibly up to half an hour). Subsequent starts will be much quicker (15 seconds). Once it is up and running, try connecting to the address/name of the Pi from the machine you usually use for running the Minecraft game client. If the connection fails due to a protocol error, this usually means that the server is too old to cope with the latest version of the game client, so you need to find a new server. If it fails due to a timeout, then it means that your Pi isn’t running fast enough. Tweak settings. Overclock more, etc. There are various settings in the “server-properties” file that you can tweak to improve the speed at which the server runs. Disabling “nether” and dropping the view distance down (to, say, 5) seem to be particularly effective. Again, you can find out more about this by googling around. My current server-properties looks like this:
#Minecraft server properties #Sat Nov 30 14:23:39 UTC 2013 generator-settings= op-permission-level=4 allow-nether=false level-name=world enable-query=false allow-flight=false announce-player-achievements=true server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=true spawn-animals=true hardcore=false snooper-enabled=true texture-pack= online-mode=true resource-pack= pvp=true difficulty=1 enable-command-block=false player-idle-timeout=0 gamemode=0 max-players=10 spawn-monsters=true generate-structures=true view-distance=5 spawn-protection=16 motd=Pi server
If you’ve never set up a server before and are having trouble, it may be easier to set things up on another machine and then copy things across to the Pi when you get it working. I actually got mine up and running on a fast Ubuntu laptop first, which saved a lot of time.
I’m still running the Mojang server. It’s generally fine, but gives lots of warnings about “Not keeping up”, and riding horses doesn’t really work very well. If anyone has suggestions for another server that will work as a swap-in replacement and run better on the Pi, please do leave a comment. I’d be interested in something that runs a bit faster, and copes better with riding horses, smashing blocks, etc. But my kids will not be pleased if they have to re-build their world…