By default, the server configuration will be created and set based on the following environment variables, but only the first time the server is started. If the `server.properties` file already exists, the values in them will not be changed.
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=""`. A variables that maps to a server property that is unset, is ignored and the existing `server.property` is left unchanged.
Any of the server properties mapped from the environment variables [below](#properties), may contain placeholders that are replaced when the `server.properties` file is updated. The syntax of placeholders is DOS-style, `%VAR%` to avoid being processed by Docker or the shell.
The following options are available for placeholders:
`%VAR%`
: Replaced with the value of the environment variable `VAR`
`%env:VAR%`
: Also, replaced with the value of the environment variable `VAR`
`%date:FMT%`
: The `FMT` string is processed by [Java's DateTimeFormatter](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/format/DateTimeFormatter.html) and the current date/time is formatted.
Any declared or resolved environment variable may be referenced, such as `VERSION` and `TYPE`. Additionally, [Modrinth](../types-and-platforms/mod-platforms/modrinth-modpacks.md) and [Auto CurseForge](../types-and-platforms/mod-platforms/auto-curseforge.md) modpacks will expose the environment variables `MODPACK_NAME` and `MODPACK_VERSION`.
!!! example
As a compose file environment entry:
```yaml
MOTD: Running %MODPACK_NAME% version %env:MODPACK_VERSION%
The section symbol (§) and other unicode characters are automatically converted to allow [formatting codes](https://minecraft.wiki/w/Formatting_codes) to be used consistently with all server versions. For example,
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".
: 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.
To [enforce the whitelist changes immediately](https://minecraft.wiki/w/Server.properties#enforce-whitelist) 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.
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.
: 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.
New to [22W42A](https://www.minecraft.net/en-us/article/minecraft-snapshot-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".
**DO NOT MAP THE RCON PORT EXTERNALLY** unless you 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
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
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](../data-directory.md) 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.
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:
