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Minecraft (Java) Server in Docker on a Synology NAS

Please note if you are using DSM7.2 or higher you should use the Container Manager version of this guide from the menu.
This guide has reached the end of its updates as most people are now on the latest DSM update - This guide is correct as of 08/12/2023 however no further updates will be added.
Added a note in relation to enabling the RCON port and if you expose it to the internet you MUST change the default password.22/04/2023
Historic updates now at the end of the guide.

In this guide I am going to take you through the steps to get a Minecraft JAVA server up and running in Docker on a Synology NAS. If you are looking to host a server for a Console or Mobile you will want to see my Bedrock edition guide.

The fantastic documentation on how to use the server once it is running can be found here

Let’s Begin

In order for you to successfully use this guide please complete the setting up a docker user guide, or have your ID details to hand.

Step 2: Setting up a restricted Docker user
Step 3: Setting Up a Docker Bridge Network

Downloading the Container

Open up Docker within DSM and navigate to the ‘Registry’ tab and search for ITZG in the keyword box.

Within the results right click and download the ‘ITZG|Minecraft-Server’, When it asks which version number to download select the one that you require based on the table below

Minecraft VersionTag to Select
v1.18x and upLatest or JAVA17
v1.16 and belowJAVA15

Setting up the container

Now we have downloaded the container and got hold of our user IDs we can move onto the next stage.

Go back into Docker and click on the ‘Image’ tab, in the list of your containers select the ITZG Minecraft server, and click on ‘Launch’

You will be greeted with the Network screen, we will be using the ‘synobridge’ network we created earlier select it from the list and click Next.

Next you will be greeted with the General Settings screen, this is where you can start specifying some of your preferences.

Minecraft can be fairly CPU heavy so if you are running the server on a lower specification Synology box you will probably want to set limits around the CPU priority or Memory Limit. This will ensure DSM is still usable when the server is running.

You can change the name of the container to anything you like, and you may want to enable Auto Restart as this will ensure the server starts automatically if you reboot your NAS.

Next up we are going to click on the ‘Advanced Settings’ button, this will take you to a new window with a number of tabs which we are going to work through.

Environment Variables – GID, UID, Server Type and EULA

We are now going to set up the specific options for the server including what type of server you would like to run and even a specific version.

Each of the values below are added by clicking the ‘Add’ button at the top of the screen and then entering each of the values below

Please note if you decide to enable the RCON Port please change the default password especially if you open your server up to the Internet! See the GitHub for more details.

UIDThis will be prefilled with 1000 change it to the UID you obtained earlier
GIDThis will be prefilled with 1000 change it to the GID you obtained earlier
EULATRUEThis accepts the Minecraft EULA, without this the server will not run
TYPESPIGOTYou can change this as per the list below
VERSIONLATESTYou can change this to any a specific version if you want e.g 1.13
JVM_XX_OPTS-XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:InitiatingHeapOccupancyPercent=15These variables are used to increase the performance of the server – Copy and paste this exactly
MAX_MEMORY2GAmend the number to the amount of memory you want to allocate to the server this will depend on your system or server type you are running

Server Types


See the full list here

You do not need to set up anything on these tabs.

Press ‘Save’ to go back to the initial setup screen, then press ‘Next’

Port Settings

You will now see the Port Settings screen. You will need to type in the ‘Local Port’ to match the ‘Container Port’ shown on the right-hand side this will avoid the container being assigned random ports when it is started. When set press Next.

As per the earlier note if you decide to enable RCON you will need to add its port mapping here.

Volume Settings

We can now specify the directory where Minecraft will store its configuration files.

Click on Add Folder, click on the docker folder and create a new sub-folder called ‘minecraft’ select this folder and click ‘select’

Now we need to specify where this folder will be mounted inside the container. As per the screenshot/table below, enter /data into the ‘Mount path’.

File/FolderMount path

Click on Next and you will be taken to an overall summary screen, just do a quick sanity check to make sure the options are correct. If you want to launch the server immediately check the box and click on Done.

Server startup time

The first time the server launches it may take a few minutes for the server files to download and the world to be generated. You can track the progress by going into the ‘Containers’ tab and clicking on details for the Minecraft container, then either viewing the terminal or log tabs.

All other server settings can be configured using the standard Minecraft file, I won’t be covering that here as there are extensive other guides out there.

Update HistoryDate
Added Docker Compose details03/05/2021
Updated to show which version of the image to download09/06/2021
Cleaned up the Environment Variables section and included some new JAVA optimisations24/11/2021
Screenshots update to DSM7 and tweaked the guide wording22/01/2022
DSM7.1 Update with new screenshots and steps24/05/2022
Added new port settings and Docker Bridge Network23/07/2022
Fixed the missing port settings section!16/11/2022
Removed port 25575 (RCON) as could pose a security issue if exposed to the internet – You can add manually if required12/03/2023
Compose version number removed 3.x not required, and some minor wording amendments.08/04/2023
Amended the path to save the compose file – this is for security, so the container has no access to the file contents.14/04/2023
Update History

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Published inGaming 7.1


  1. Brandon Brandon

    Thank you for a great tutorial. I think it would be wise to add a very important detail, Remote Console “RCON” is enabled by default with this docker container and uses a default password “minecraft”. Anyone setting up a server needs change the this password immediately during your “Environment Variables” process. I learned this the hard way as a white hat hacker connected to my server with RCON, added himself to my whitelist, and left command blocks at spawn warning me of the vulnerability.

    • Dr_Frankenstein Dr_Frankenstein

      Hey, Thanks for the feedback I removed the RCON port from the guide back in March as the Dev reached out to me as well. I didn’t realise this at the time. I will also pop a note to say if you do decide to add it then to change the password.

  2. 3ambit 3ambit

    Hey there,

    thanks for your nice tutorial! The container on my NAS (423+) consumes only ~7% of CPU and round about 570MB RAM. After 30min I still can not access NAS-IP: 25565 and details on log says: [Worker-Main-4/INFO]: Preparing spawn area: 3%.
    Is this normal?

    • Dr_Frankenstein Dr_Frankenstein

      Hey – It can be a little slow on the first run, did it eventually progress? Even on the Ryzen CPU it should be quicker than 30 mins as its faster than the old Atom CPU I used to run mine on..

  3. Pascal Pascal

    Great Guide! This was very helpful to setup a little server me and a couple of friends can play on from time to time. I however have run into a problem with my NAS Firewall settings. If I completely disable my Firewall settings on the NAS everything runs perfectly and connections to the server can be made. As soon as I turn them back on though is where my headache starts. Even If i allow port 25565 in my settings I cannot connect to the server anymore. Any Idea why this might be happening or how I might fix it? Thank you again and have a great rest of your day/night 🙂

    • Dr_Frankenstein Dr_Frankenstein

      Hey – if you are adding any exceptions make sure they are above the final Block All rule at the bottom of the list – Failing that I could probably do with a screenshot – hit me up on my contact page.

  4. Can you please revise the “Port Settings” section to remove the port mapping of RCON port 25575 or clarify that RCON_PASSWORD must be changed? Without that change, it is very easy for users to inadvertently allow admin-level access to the public internet.

    The current and future image builds will no longer pre-expose 25575; however, it will avoid confusion if this article is also changed.

  5. Luke Luke

    Randomly I noticed that my Synology CPU usage was over 90% without explanation. After much head scratching I checked on Docker and saw that the Minecraft server for java was bouncing between 90% and 0% CPU usage. Basically it boots up then crashes after extraordinary CPU load and then reboots. I’ve not changed anything on the server or settings in months. Unsure of how long this has been going on for (no too long, I don’t think, maybe a couple of days at most). Are you aware of anything that could cause this issue?

    • Dr_Frankenstein Dr_Frankenstein

      I could do with the logs to be honest to see what is happening. Can you ping me an email via my contact page we can then have a look 🙂

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