Server properties

In order to unify management of the Minecraft server container, all of the server.properties entries can be managed by the environment variables described in the sections below. Some of the mappings provide additional functionality above and beyond the properties file.

If you prefer to manually manage the server.properties file, set OVERRIDE_SERVER_PROPERTIES to "false". Similarly, you can entirely skip the startup script's creation of server.properties by setting SKIP_SERVER_PROPERTIES to "true".

Note

To clear a server property, set the variable to an empty string, such as -e RESOURCE_PACK="". An unset variable is ignored and the existing server.property is left unchanged.

Placeholders

When declaring a server properties via container environment variables, those values may contain placeholders that are processed when the server.properties file is updated.

The syntax of placeholders is DOS-style, %VAR%, to avoid being processed by Docker or the shell and the following options are available:

%VAR% or %env:VAR%

Replaced with the resolved value or the environment variable VAR

%date:FMT%

Formats the current date/time with the given FMT string processed by Java's DateTimeFormatter.

Any declared or resolved environment variable may be referenced, such as VERSION and TYPE. Additionally, Modrinth and Auto CurseForge modpacks will expose the environment variables MODPACK_NAME and MODPACK_VERSION. The originally declared version, such as "LATEST" or "SNAPSHOT", is available in the variable DECLARED_VERSION

Example

As a compose file environment entry:

    MOTD: Running %MODPACK_NAME% version %env:MODPACK_VERSION%
    LEVEL: world-%date:yyyy-MM-dd%

Warning

Placeholders are not supported when manually managing server.properties

Properties

Message of the Day

The message of the day, shown below each server entry in the client UI, can be changed with the MOTD environment variable or a default is computed from the server type and version, such as

A Paper Minecraft Server powered by Docker

That way you can easily differentiate between several server types you may have started.

The section symbol (§) and other unicode characters are automatically converted to allow formatting codes to be used consistently with all server versions. For Minecraft versions less than 1.20, unicode characters in server.properties will be escaped as \uXXXX, by default. That behavior can be altered by setting SERVER_PROPERTIES_ESCAPE_UNICODE to "true" or "false".

Example

With docker run

 -e MOTD="A §l§cMinecraft§r §nserver"

or within a compose file

environment:
  MOTD: "A §l§cMinecraft§r §nserver"

renders

To produce a multi-line MOTD, embed a newline character as \n in the string, such as

-e MOTD="Line one\nLine two"

Tip

You can also embed configured and resolved environment variables using placeholders.

Difficulty

The difficulty level (default: easy) can be set like:

docker run -d -e DIFFICULTY=hard ...

Valid values are: peaceful, easy, normal, and hard, and an error message will be output in the logs if it's not one of these values.

Refer to the Minecraft wiki

Whitelist Players

For public servers

It is very important to consider setting a whitelist of expected players.

To whitelist players for your Minecraft server, you can:

• Provide a list of usernames and/or UUIDs separated by commas or newlines via the WHITELIST environment variable
• Provide the URL or container path to a whitelist file via WHITELIST_FILE that will be retrieved/copied into the standard location

Example

In a compose file, a text block can be used to improve maintainability, such as

      WHITELIST: |
        user1
        user2
        user3

When either is set, whitelisting of connecting users is enabled.

To change the behavior when the whitelist file already exists, set the variable EXISTING_WHITELIST_FILE to one of the following options:

SKIP (default)

Skip processing of the whitelist file when one is already present. This is the same as setting the legacy variable OVERRIDE_WHITELIST to "false".

SYNCHRONIZE

Synchronize the list of users in the file with the WHITELIST or WHITELIST_FILE provided. When using both, WHITELIST will take precedence. This is the same as setting the legacy variable OVERRIDE_WHITELIST to "true".

MERGE

Merge the list of users from WHITELIST into the existing file. WHITELIST_FILE cannot be used with this option.

SYNC_FILE_MERGE_LIST

When WHITELIST_FILE is provided it will overwrite an existing whitelist file. Also, if WHITELIST is provided, then those users will be merged into the newly copied file.

Note

For versions prior to 1.7.3, white-list.txt will be maintained instead. Only usernames are supported for those versions.

To enforce the whitelist changes immediately when whitelist commands are used , set ENFORCE_WHITELIST to "true". If managing the whitelist file manually, ENABLE_WHITELIST can be set to "true" to set the white-list property.

Changing user API provider

The usernames provided for whitelist and ops processing are resolved using either PlayerDB or Mojang's API. The default uses PlayerDB, but can be changed by setting the environment variable USER_API_PROVIDER to "mojang". Sometimes one or the other service can become overloaded, which is why there is the ability to switch providers.

Op/Administrator Players

Similar to the whitelist, users can be provisioned as operators (aka administrators) to your Minecraft server by

• Providing a list of usernames and/or UUIDs separated by commas or newlines via the OPS environment variable
• Providing the URL or container path to an ops file via OPS_FILE that will be retrieved/copied into the standard location

Example

In a compose file, a text block can be used to improve maintainability, such as

      OPS: |
        user1
        user2
        user3

To change the behavior when the ops file already exists, set the variable EXISTING_OPS_FILE to one of the following options:

SKIP (default)

Skip processing of the ops file when one is already present. This is the same as setting the legacy variable OVERRIDE_OPS to "false".

SYNCHRONIZE

Synchronize the list of users in the file with the OPS or OPS_FILE provided. When using both, OPS will take precedence. The level and bypassesPlayerLimit will be retained from previous entries. This is the same as setting the legacy variable OVERRIDE_OPS to "true".

MERGE

Merge the list of users from OPS into the existing file. OPS_FILE cannot be used with this option.

SYNC_FILE_MERGE_LIST

When OPS_FILE is provided it will overwrite an existing ops file. Also, if OPS is provided, then those users will be merged into the newly copied file.

Note

For versions prior to 1.7.3, ops.txt will be maintained instead. Only usernames are supported for those versions.

Enable/disable initial selection of datapacks

New to 22W42A, datapacks with feature flags can be controlled before initial world creation by setting these to a comma separated list of packs:

• INITIAL_ENABLED_PACKS such as "update_1_20,bundle"
• INITIAL_DISABLED_PACKS

Server icon

A server icon can be configured using the ICON variable. The image will be automatically downloaded, scaled, and converted from any other image format:

docker run -d -e ICON=http://..../some/image.png ...

The server icon which has been set doesn't get overridden by default. It can be changed and overridden by setting OVERRIDE_ICON to TRUE.

docker run -d -e ICON=http://..../some/other/image.png -e OVERRIDE_ICON=TRUE...

RCON

RCON is enabled by default to allow for graceful shut down the server and coordination of save state during backups. RCON can be disabled by setting ENABLE_RCON to "false".

Warning

Disabling RCON will remove and limit some features, such as interactive and color console support.

The default password is randomly generated on each startup; however, a specific one can be set with RCON_PASSWORD.

DO NOT MAP THE RCON PORT EXTERNALLY unless you are aware of all the consequences and have set a secure password with RCON_PASSWORD.

Info

Mapping ports (-p command line or ports in compose) outside the container and docker networking needs to be a purposeful choice. Most production Docker deployments do not need any of the Minecraft ports mapped externally from the server itself.

By default, the server listens for RCON on port 25575 within the container. It can be changed with RCON_PORT but only do this if you have a very good reason. DO NOT change rcon.port via server.properties or integrations will break.

Query

Enabling this will enable the gamespy query protocol. By default the query port will be 25565 (UDP) but can easily be changed with the QUERY_PORT variable.

docker run -d -e ENABLE_QUERY=true

Max players

By default max players is 20, you can increase this with the MAX_PLAYERS variable.

docker run -d -e MAX_PLAYERS=50

Max world size

This sets the maximum possible size in blocks, expressed as a radius, that the world border can obtain.

docker run -d -e MAX_WORLD_SIZE=10000

Allow Nether

Allows players to travel to the Nether.

docker run -d -e ALLOW_NETHER=true

Announce Player Achievements

Allows server to announce when a player gets an achievement.

docker run -d -e ANNOUNCE_PLAYER_ACHIEVEMENTS=true

Enable Command Block

Enables command blocks

 docker run -d -e ENABLE_COMMAND_BLOCK=true

Force Gamemode

Force players to join in the default game mode.

• false - Players will join in the gamemode they left in.
• true - Players will always join in the default gamemode.

docker run -d -e FORCE_GAMEMODE=false

Generate Structures

Defines whether structures (such as villages) will be generated.

• false - Structures will not be generated in new chunks.
• true - Structures will be generated in new chunks.

docker run -d -e GENERATE_STRUCTURES=true

Hardcore

If set to true, players will be set to spectator mode if they die.

docker run -d -e HARDCORE=false

Snooper

If set to false, the server will not send data to snoop.minecraft.net server.

docker run -d -e SNOOPER_ENABLED=false

Max Build Height

The maximum height in which building is allowed. Terrain may still naturally generate above a low height limit.

docker run -d -e MAX_BUILD_HEIGHT=256

Max Tick Time

The maximum number of milliseconds a single tick may take before the server watchdog stops the server with the message, A single server tick took 60.00 seconds (should be max 0.05); Considering it to be crashed, server will forcibly shutdown. Once this criteria is met, it calls System.exit(1). Setting this to -1 will disable watchdog entirely

docker run -d -e MAX_TICK_TIME=60000

Spawn Animals

Determines if animals will be able to spawn.

docker run -d -e SPAWN_ANIMALS=true

Spawn Monsters

Determines if monsters will be spawned.

docker run -d -e SPAWN_MONSTERS=true

Spawn NPCs

Determines if villagers will be spawned.

docker run -d -e SPAWN_NPCS=true

Set spawn protection

Sets the area that non-ops can not edit (0 to disable)

docker run -d -e SPAWN_PROTECTION=0

View Distance

Sets the amount of world data the server sends the client, measured in chunks in each direction of the player (radius, not diameter). It determines the server-side viewing distance.

docker run -d -e VIEW_DISTANCE=10

Level Seed

If you want to create the Minecraft level with a specific seed, use SEED, such as

-e SEED=1785852800490497919

If using a negative value for the seed, make sure to quote the value such as:

-e SEED="-1785852800490497919"

Game Mode

By default, Minecraft servers are configured to run in Survival mode. You can change the mode using MODE where you can either provide the standard numerical values or the shortcut values:

• creative
• survival
• adventure
• spectator (only for Minecraft 1.8 or later)

For example:

docker run -d -e MODE=creative ...

PVP Mode

By default, servers are created with player-vs-player (PVP) mode enabled. You can disable this with the PVP environment variable set to false, such as

docker run -d -e PVP=false ...

Level Type and Generator Settings

By default, a standard world is generated with hills, valleys, water, etc. A different level type can be configured by setting LEVEL_TYPE to an expected type listed here.

For some of the level types, GENERATOR_SETTINGS can be used to further customize the world generation.

To configure the GENERATOR_SEETINGS you need to add the appropriate GeneratorOptions JSON configuration. In the case of a superflat world, you may omit the flat_world_options.

The layers are applied from -64 and up and are added in the order of the list

Example for a superflat world:

• 1x bedrock
• 2x stone
• 15x sandstone
• Desert biome

LEVEL_TYPE: FLAT
GENERATOR_SETTINGS: >-4
    {
        "layers": [
            {
                "block": "minecraft:bedrock",
                "height": 1
            },
            {
                "block": "minecraft:stone",
                "height": 2
            },
            {
                "block": "minecraft:sandstone",
                "height": 15
            }
        ],
        "biome": "minecraft:desert"
    }

For more details, check the official wiki.

Custom Server Resource Pack

You can set a link to a custom resource pack and set it's checksum using the RESOURCE_PACK and RESOURCE_PACK_SHA1 options respectively, the default is blank:

docker run -d -e 'RESOURCE_PACK=http://link.com/to/pack.zip?=1' -e 'RESOURCE_PACK_SHA1=d5db29cd03a2ed055086cef9c31c252b4587d6d0'

You can enforce the resource pack on clients by setting RESOURCE_PACK_ENFORCE to TRUE (default: FALSE).

Level / World Save Name

You can either switch between world saves or run multiple containers with different saves by using the LEVEL option, where the default is "world":

docker run -d -e LEVEL=bonus ...

NOTE: if running multiple containers be sure to either specify a different -v host directory for each LEVEL in use or don't use -v and the container's filesystem will keep things encapsulated.

INFO Refer to the data directory section for a visual description of where the $LEVEL directory is situated.

Online mode

By default, server checks connecting players against Minecraft's account database. If you want to create an offline server or your server is not connected to the internet, you can disable the server to try connecting to minecraft.net to authenticate players with environment variable ONLINE_MODE, like this

docker run -d -e ONLINE_MODE=FALSE ...

Allow flight

Allows users to use flight on your server while in Survival mode, if they have a mod that provides flight installed.

-e ALLOW_FLIGHT=TRUE|FALSE

Server name

The server name (e.g. for bungeecord) can be set like:

docker run -d -e SERVER_NAME=MyServer ...

Server port

WARNING: only change this value if you know what you're doing. It is only needed when using host networking and it is rare that host networking should be used. Use -p port mappings instead.

If you must, the server port can be set like:

docker run -d -e SERVER_PORT=25566 ...

however, be sure to change your port mapping accordingly and be prepared for some features to break.

Custom server properties

Some mods/plugins utilize custom server.properties entries which can be declared via the CUSTOM_SERVER_PROPERTIES environment variable. The contents must be newline delimited name=value pairs.

Within a compose file, newline delimited entries can be declared as shown here:

      CUSTOM_SERVER_PROPERTIES: |
        custom1=value1
        defaultworldgenerator-port=f8c04631-f744-11ec-b260-f02f74b094e0

When using docker run from a bash shell, the entries must be quoted with the $' syntax, such as

-e CUSTOM_SERVER_PROPERTIES=$'k1=v1\nk2=v2'

Other server property mappings

Environment Variable	Server Property
BROADCAST_CONSOLE_TO_OPS	broadcast-console-to-ops
BROADCAST_RCON_TO_OPS	broadcast-rcon-to-ops
ENABLE_STATUS	enable-status
ENFORCE_SECURE_PROFILE	enforce-secure-profile
ENTITY_BROADCAST_RANGE_PERCENTAGE	entity-broadcast-range-percentage
FUNCTION_PERMISSION_LEVEL	function-permission-level
NETWORK_COMPRESSION_THRESHOLD	network-compression-threshold
OP_PERMISSION_LEVEL	op-permission-level
PLAYER_IDLE_TIMEOUT	player-idle-timeout
PREVENT_PROXY_CONNECTIONS	prevent-proxy-connections
SIMULATION_DISTANCE	simulation-distance
SYNC_CHUNK_WRITES	sync-chunk-writes
USE_NATIVE_TRANSPORT	use-native-transport