MSCS is the tool I use to keep my minecraft servers up to date and running well.

Minecraft Server Control Script (MSCS) is a server-management script for UNIX and Linux powered Minecraft servers.

Today I ran the update command to update to minecraft version 1.20.6 and the server would not start!

Long story, I was getting this issue:

Error starting the server: couldn’t retrieve the server’s process ID

Which mscs clearly states is because of the java installation being out of date:

This is usually due to an outdated java installation on your machine when trying to start the minecraft server. Verify that the java version required for your minecraft server version is installed on your machine.

I'm Running Java version 17, but I need 21

A developer blog fabricmc shared that the Java Development Kit, JDK being used by Minecraft 1.20.6 requires version 21. That's a huge jump from JDK version 17!!

This also marks the end of 32-bit support.

GUIDE: Installing JDK Version 22

Version 17 is as far as my apt-get package manager gets me, so we have to do a manual install.

My server is running Debian 11 x64 (bullseye) so I chose Linux/x64.
If you're following along to fix this on your own server, make sure you pick the right one.
Find openJDK version 22 here: https://jdk.java.net/22/

Steps to Install

Navigate in your server to the directory where you want this JDK installation to live
use wget to download the jdk-package.tar.gz to the server
unzip with tar xvzf the downloaded jdk-package.tar.gz
export to the $PATH variable
edit to add the variables to ~/.bashrc file
Should be good now, (Disclaimer: I do not know if this breaks other programs that depend on older JDK such as old minecraft servers)
Here's the commands I used on my server:

lang-bash

      
          
 cd /usr/lib/jvm/
 wget "https://download.java.net/java/GA/jdk22.0.1/c7ec1332f7bb44aeba2eb341ae18aca4/8/GPL/openjdk-22.0.1_linux-x64_bin.tar.gz"
tar xvzf openjdk-22.0.1_linux-x64_bin.tar.gz 
cd jdk-22.0.1/bin

#outputs the version if successful
./java -version
cd ../..

# clean up the file tar.gz
rm openjdk-22.0.1_linux-x64_bin.tar.gz

# also add these two lines to the ~/.bashrc file
export JAVA_HOME=/user/lib/jvm/jdk-22.0.1
export PATH="$JAVA_HOME/bin:$PATH"

nano ~/.bashrc

Alright! almost done...

Permission denied error

Also, I got a permission denied error so I followed the troubleshooting guide:

If you get a permission denied error when attempting to run a mscs command, please ensure that the minecraft user has the correct permissions set:

lang-bash

      
          
chmod -R u+w /opt/mscs
chown -R minecraft:minecraft /opt/mscs

lang-shell

      
          
root@vultr:/opt# chmod -R u+w /opt/mscs
root@vultr:/opt# chown -R minecraft:minecraft /opt/mscs

root@vultr:/opt# mscs restart
The cached copy of the version manifest is up to date.
Use the force-update option to ensure a new copy is downloaded.
.estarting Minecraft Server: newWorld
root@vultr:/opt# https://minecraftservercontrol.github.io/docs/mscs^C
root@vultr:/opt# vim ~/.bashrc
root@vultr:/opt# cd 
root@vultr:/opt/mscs/worlds/newWorld# mscs status newWorld
Minecraft Server Status:
  newWorld: running version 1.20.6 (0 of 20 users online).
    Port: 25565.
    Memory used: 1.7GB (3GB allocated).
    Process ID: 708053.
root@vultr:/opt/mscs/worlds/newWorld#

Success!

Closing

Not super easy, but I guess I learned how to install a package manually without your package manager. Alright that's all for now blockheads, happy server managing!

Sources