alifeee's notes - automating the turning on and off of my Minecraft server

automating the turning on and off of my Minecraft server#source

2025-06-10 • tags: minecraft, scripting, tmux, cron, nginx • 1112 'words', 334 secs @ 200wpm

I run a Minecraft server weekly on Tuesdays. Sometimes, I even play on it.

This describes automating the process for turning it on and off. Won't somebody at https://ggservers.com/ please hire me /jk.

The process

Turning it on

My process every Tuesday to turn on the server has been:

log on to https://console.kamatera.com/ (requiring a One-Time-Password so I need my phone)
go to "servers" and click "power on" for the server titled "Minecraft server" (minecraft box)
wait a bit for it to power up, and connect via ssh (sometimes I just run `while true; do ssh minecraft; sleep 2; done)
start a tmux session and run ./run to turn on the Minecraft server
disconnect from the tmux session and from the minecraft box
connect to my web server and change map.mc.alifeee.net to 301 redirect to livemap.mc.alifeee.net

Turning it off

Then, on Wednesday mornings (if I remember), I:

ssh onto the minecraft box
connect to the tmux session and stop the Minecraft server with CTRL+C
connect to my web server and use rsync to copy the world and dynmap files as backups (this takes about 3 minutes)
(still on the web server) switch off the 301 redirect
run sudo shutdown on the minecraft box to turn it off

The problems

Each of these steps can take a few seconds to run, so I am often multitasking, and I often forget things (like forgetting the backup, forgetting to actually run shutdown after all is done).

So, I've tried to automate it.

Doing it automatically

I found out that Kamatera (the server host) has an API that you can use to remotely turn on/off servers, which is the only thing that I was really missing.

cron tasks - web server

Here are the cron tasks on my web server:

# turn Minecraft server server on/off
45 16 * * 2 /home/alifeee/minecraft/togglepower.sh on >> /home/alifeee/minecraft/cron.log 2>&1
5 4 * * 3 /home/alifeee/minecraft/rsync_backup.sh on >> /home/alifeee/minecraft/cron.log 2>&1
15 4 * * 3 /home/alifeee/minecraft/togglepower.sh off >> /home/alifeee/minecraft/cron.log 2>&1

cron tasks - minecraft box

…and the cron tasks on the minecraft box:

55 16 * * 2 /home/alifeee/minecraft/tmux_make.sh >> /home/alifeee/minecraft/cron.log 2>&1
0 4 * * 2 /home/alifeee/minecraft/tmux_kill.sh >> /home/alifeee/minecraft/cron.log 2>&1

human description of cron jobs

Hopefully you can see the similarities to the process I described above, i.e.,

16:45 turn minecraft box on
16:55 (10 minutes later) turn minecraft server on
04:00 (11 hours and 5 minutes later) turn minecraft server off
04:05 (5 minutes later) fetch backup
04:15 (10 minutes later) turn minecraft box on

The scripts

These scripts are pretty simple, they are:

togglepower.sh - turn on/off the minecraft box

$ cat togglepower.sh
#!/bin/bash
# power on server
date
onoroff="${1}"
echo "got instruction: turn server <${onoroff}>"
if [[ ! "${onoroff}" == "on" ]] && [[ ! "${onoroff}" == "off" ]]; then
  echo "usage: ./togglepower.sh [on|off]"
  exit 1
fi
serverid="${serverid}"
auth=$(curl -s --request POST 'https://console.kamatera.com/service/authenticate' \
--header 'Content-Type: application/json' \
--data '{
    "clientId": "${clientId}",
    "secret": "${secret}"
}')
authentication=$(echo "${auth}" | jq -r '.authentication')
status=$(curl -s --request \
  GET "https://console.kamatera.com/service/server/${serverid}" \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer ${authentication}"
)
power=$(echo "${status}" | jq -r '.power')
echo "current power: ${power}"
if [[ "${power}" == "${onoroff}" ]]; then
  echo "power is already ${onoroff}… quitting…"
  exit 1
fi
result=$(curl -s --request PUT \
  "https://console.kamatera.com/service/server/${serverid}/power" \
  --header 'Content-Type: application/json' \
  -H "Authorization: Bearer ${authentication}" \
  --data '{"power": "'"${onoroff}"'"}'
)
echo "complete! got ${result} from API call"

run - run the Minecraft server

$ cat ./run 
#!/bin/bash
java \
  -Xmx1G \
  -jar fabric-server-mc.1.21.4-loader.0.16.10-launcher.1.0.1.jar \
  nogui

tmux_make.sh - make a tmux session and run the Minecraft server in it

$ cat tmux_make.sh 
#!/bin/bash
date
session="minecraft"
echo "making tmux session ${session}"
tmux new-session -d -s "${session}" -c "/home/alifeee/minecraft"
echo "sending run"
tmux send-keys -t "${session}" './run' 'C-m'
echo "created !"

tmux_kill.sh - stop the Minecraft server and stop the tmux session

$ cat tmux_kill.sh 
#!/bin/bash
date
session="minecraft"
echo "sending CTRL+C to ${session}"
tmux send-keys -t "${session}" 'C-c'
echo "sent CTRL+C… sleeping 30s…"
sleep 30
echo "killing session ${session}"
tmux kill-session -t "${session}"
echo "killed session"

rsync_backup.sh - get backups using rsync

$ cat rsync_backup.sh 
#!/bin/bash
date
echo "saving cron log"
rsync minecraft:/usr/alifeee/minecraft/cron.log cron_minecraft.log
date
echo "saving world"
rsync -r minecraft:/usr/alifeee/minecraft/world/ world/
date
echo "saving dynmap"
rsync -r minecraft:/usr/alifeee/minecraft/dynmap/web/ dynmap/web/
date
echo "done!"

What about the map?

Well, I figured this was too annoying to automate, so I just wrote a front page to pick whether you wanted the "dead map" or the "live map" (on https://map.mc.alifeee.net/ – link probably dead).

The HTML for this simple picker makes quite a nice page:

see HTML

<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<head>
<style>
html, body {
  background: black;
  color: white;
  height: 100%;
  font-family: sans-serif;
}
body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
img {
  margin-bottom: 1rem;
}
.options {
  display: flex;
}
.option {
  background: orange;
  padding: 1rem;
  border-radius: 0.5rem;
  margin: 0.5rem;
  color: black;
  text-decoration: none;
  max-width: 10rem;
  text-align: center;
}
.option.two {
  background: purple;
  color: white;
}
.option span {
  opacity: 0.75;
}
</style>
</head>

<body>

<h1>minecraft dynmap</h1>

<img src="/map/tiles/world/flat/0_0/zz_16_4.webp" />

<section class="options">
  <a class="option one" href="/map/">
    <h2>dead map</h2>
    <span>viewable all week, updates on server shutdown</span>
  </a>
  <a class="option two" href="https://livemap.mc.alifeee.net/">
    <h2>live map</h2>
    <span>viewable only when the server is live, shows players</span>
  </a>
</section>
</body>
</html>

This is served with a special nginx configuration which just serves a static file, and otherwise serves content via alias (not root):

server {
    server_name map.mc.alifeee.net;
location / {
        root /var/www/dynmap/;
        try_files /whichmap.html =404;
    }
    location /map/ {
        alias /var/www/dynmap/;
        try_files $uri $uri/ =404;
    }
}

Does it work

I think it works. I'll see if I have to make any edits tomorrow or next week.

I love scripting !

notes by alifeeerss

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