Servers & modpacks
A server is one itzg/minecraft-server container that CommandBlock creates, starts, and routes to.
Create a server
From Servers → Create server, fill in:
| Field | Notes |
|---|---|
| Type | The loader: VANILLA, PAPER, PURPUR, FABRIC, QUILT, FORGE, NEOFORGE, SPIGOT, or a modpack installer (MODRINTH). Maps to the itzg TYPE. |
| Memory | Java heap / container memory, e.g. 4G. |
| Display name | Shown in the UI. |
| Hostname | The address players connect with, e.g. smp.example.com. Must be unique - it's the router's key. |
| Version | Minecraft version for plain loaders (blank = latest). Hidden for modpack types. |
| Modpack reference | For modpack types: a Modrinth slug, a .mrpack URL, or a CurseForge ref. |
On create, CommandBlock pulls the image, starts the container on its Docker network with no published port, and stamps a mc.host label the router uses. Modpacks download the server side of the pack on first boot, so the server may take a few minutes to accept connections.
What "modpack reference" means
For a public Modrinth pack, use the slug from its URL:
https://modrinth.com/modpack/cobblemon-fabric
└────── slug ──────┘itzg installs the server side of that pack automatically - you don't upload your client instance. A self-built pack has no slug; export it as a .mrpack and pass its URL instead.
Lifecycle
Each server row supports Start, Stop, and Delete. Delete removes the container and its world data (host folder or volume, per your storage setting).
Settings
Each server has a Settings modal (reachable from the row's kebab menu or the detail header) grouping everything you'd tweak after create:
- General / MOTD - the most-used
server.propertieswith a live MOTD editor, plus the server's display name (rename). - Runtime - memory, Java version, Aikar/JVM flags, and extra itzg env vars (applied on the next restart).
- Wake & sleep - start on join (with a join queue) and auto-sleep when idle, per server.
- Icon - upload a PNG; it's cropped to the 64×64 server-icon and shown in the UI and in-game.
Backups
Snapshot a server's world, or take a full-server backup you can restore or clone a new server from. See Backups.
Connecting
Add each server in the Minecraft client by its hostname (e.g. smp.example.com). See Hostname routing for the DNS + firewall setup.