Minecraft modpacks meet alpine

This repository contains servers for minecraft modpacks like FTB:

By using this container you agree to the Minecraft Eula

Getting Started

1. Which server you want? Which version you want? Choose you Tag below like DungeonsDragonsAndSpaceShuttles-7.4a-1.12.2
2. Which Port? -p 25566:25565 means 25566 from internet, 25565 from inside of container
3. Do you want default jvm arguments / RAM usage and so on? Yes go next, no see Environment Variables
4. Should I enter an operator level 4? He would be also whitelisted. No go next, yes use -e ADMIN_NAME="YourNameHere"
5. Do you want your own server.properties? No go next, yes see Environmental Variables, server.properties or see Additional Informations

Example Dungeons Dragons And Space Shuttles:

docker run -d -p 25565:25565 -v minecraft:/home/docker:rw -e ADMIN_NAME="YourNameHere" -e motd="Hello Docker" jusito/docker-ftb-alpine:DungeonsDragonsAndSpaceShuttles-7.4a-1.12.2

Tags

There are two different base images which provides different java virtual machine. The alpine images are amd64/x86 with Hotspot jvm as default (like expected) and openj9 is an option, multiarch isn't supported. I test every modpack with openj9 but if it doesn't even start the server, I will not push a tag with it. (forge with 1.15+ will throw unsupported virtual machine for openj9) Every tag is tested before push but this tags are more example configurations of the base images. Every provided tag will use the recommended server properties and forge version from modpack creator - if not its a bug and please report it. If you want to use the nightly images append "-develop" to the tag.

most recent

• Explorico 1.16.5 Explorico-3.2-1.16.5
• MC Eternal MC 1.12.2 MCEternal-1.4.4-1.12.2
• RoguelikeAdventuresAndDungeons MC 1.12.2 RoguelikeAdventuresAndDungeons-1.46a-1.12.2
• SevTechAges MC 1.12.2 SevTechAges-3.2.1-1.12.2
• Valhelsia 2 MC 1.15.2 Valhelsia2-2.3.3-1.15.2
• Valhelsia 3 MC 1.16.5 Valhelsia3-3.4.2a-1.16.5
• Vanilla Minecraft Vanilla-1.17.1
• DungeonsDragonsAndSpaceShuttles MC 1.12.2 DungeonsDragonsAndSpaceShuttles-8.0r1-1.12.2

other

• FTB Infinity Evolved MC 1.7.10 FTBInfinity-3.1.0-1.7.10 FTBInfinity-3.1.0-1.7.10-openj9
• FTB Continuum MC 1.12.2 FTBContinuum-1.6.0-1.12.2 FTBContinuum-1.6.0-1.12.2-openj9
• FTB Presents Direwolf20 MC 1.12.2 FTBPresentsDirewolf20-2.5.0-1.12.2 FTBPresentsDirewolf20-2.5.0-1.12.2-openj9
• FTB Presents SkyFactory 3 MC 1.10.2 FTBPresentsSkyfactory3-3.0.21-1.10.2 FTBPresentsSkyfactory3-3.0.21-1.10.2-openj9
• FTB Presents Stoneblock 2 FTBPresentsStoneblock2-1.16.0-1.12.2 FTBPresentsStoneblock2-1.16.0-1.12.2-openj9
• FTB Revelation MC 1.12.2 FTBRevelation-3.2.0-1.12.2 FTBRevelation-3.2.0-1.12.2-openj9
• FTB Ultimate Reloaded FTBUltimateReloaded-1.9.0-1.12.2 FTBUltimateReloaded-1.9.0-1.12.2-openj9
• RLCraft RLCraft-2.8.2-1.12.2 RLCraft-2.8.2-1.12.2-openj9
• SkyFactory 4 MC 1.12.2 SkyFactory4-4.2.2-1.12.2

no Tag found?

• Tag: 8jre-alpine-hotspot or 8jre-alpine-openj9 (unsure -> pick hotspot!)
• First argument: Link to server download
• Second argument: MD5 of server download
• You are done

Example: docker run [...] jusito/docker-ftb-alpine:8jre-alpine-hotspot "https://media.forgecdn.net...server.zip" "*md5 of server*"

Environment Variables

Example: docker [...] -e JAVA_PARAMETERS="-Xms4G -Xmx4G" [...] jusito/docker-ftb-alpine:*TAG*

JAVA_PARAMETERS (JVM Arguments, Performance)

• default for hotspot -Xms4G -Xmx4G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:+UseStringDeduplication -XX:+UseCGroupMemoryLimitForHeap
• default for openj9 -Xms4096M -Xmx4096M -Xmns2048M -Xmnx3276M -Xgc:concurrentScavenge -Xgc:dnssExpectedTimeRatioMaximum=3 -Xgc:scvNoAdaptiveTenure -Xdisableexplicitgc -Xtune:virtualized
• reddit suggestion, good for clients -XX:+UseG1GC -Xmx4G -Xms4G -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
• aikar suggestion: link
• Iam using for DDSS server: -Xms8192M -Xmx8192M -XX:+UseStringDeduplication -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=40 -XX:G1MaxNewSizePercent=50 -XX:G1HeapRegionSize=16M -XX:G1ReservePercent=15 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=20 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true

Server Properties

Because you may want to use many environment variables, you may find --env-file helpful. The values of this environment variables are written on every restart. If you don't set them, default value is written.

Name	Default	Description
OVERWRITE_PROPERTIES	true	server.properties are deleted and rewritten at each restart. Unused variables remain on default. Unknown properties are deleted.

In general Propertyname = Variablename, lowercase and replace "-"&"." with "_". See below for details.

All Available Properties (click me)

Name	Default	Name in server.properties
allow_flight	false	allow-flight
allow_nether	true	allow-nether
broadcast_console_to_ops	true	broadcast-console-to-ops
difficulty	1	difficulty
enable_command_block	false	enable-command-block
enable_jmx_monitoring	false	enable-jmx-monitoring=false
enable_query	false	enable-query
enable_rcon	false	enable-rcon
enable_status	true	enable-status
enforce_whitelist	false	enforce-whitelist
entity_broadcast_range_percentage	100	entity-broadcast-range-percentage
force_gamemode	false	force-gamemode
function_permission_level	2	function-permission-level
gamemode	0	gamemode
generate_structures	true	generate-structures
generator_settings		generator-settings
hardcore	false	hardcore
level_name	world	level-name
level_seed		level-seed
level_type	DEFAULT	level-type
max_build_height	256	max-build-height
max_players	20	max-players
max_tick_time	60000	max-tick-time
max_world_size	29999984	max-world-size
motd	A Minecraft Server
network_compression_threshold	256	network-compression-threshold
online_mode	true	online-mode
op_permission_level	4	op-permission-level
player_idle_timeout	0	player-idle-timeout
prevent_proxy_connections	false	prevent-proxy-connections
pvp	true	pvp
query_port	25565	query.port
rate_limit	0	rate-limit
rcon_password		rcon.password
rcon_port	25575	rcon.port
resource_pack		resource-pack
resource_pack_sha1		resource-pack-sha1
server_ip		server-ip
server_port	25565	server-port
snooper_enabled	true	snooper-enabled
spawn_animals	true	spawn-animals
spawn_monsters	true	spawn-monsters
spawn_npcs	true	spawn-npcs
spawn_protection	16	spawn-protection
sync_chunk_writes	true	sync-chunk-writes
view_distance	10	view-distance
white_list	false	white-list

access server console

docker exec -it CONTAINER query

• show - view last 50 log lines
• end - end query
• help - call help in serverquery
• stop - call stop in serverquery
• *every other serverquery command*

Healthcheck

This container is using a health check default. It checks every 10s if the server status is available. If you don't want this use: --no-healthcheck

Name	Default	Description
HEALTH_URL	127.0.0.1	Target address for healthcheck. Maybe you want to add your external address.
HEALTH_PORT	read from server.properties	Target port for healthcheck.

additional config

Name	Default	Description
FORCE_DOWNLOAD	false	Whether the server should be downloaded every time it is restarted.
ADMIN_NAME		Set here your first admin level 4 name. This will allow you to change config ingame.
DEBUGGING	false	If true xtrace is set in every script. Very verbose!
FORGE_VERSION		Force forge version because this images always ignore the shipped forge jars (if not exact vesion configured for the image).

Internal Used (don't change please)

(click me)

Name	Default	Description
MY_USER_ID	10000
MY_GROUP_ID	10000
MY_NAME	docker
MY_HOME	/home/docker
MY_VOLUME	/home/docker
MY_FILE	TagDependency	Name of the server file.
MY_SERVER	TagDependency	Download link of the server.
MY_MD5	TagDependency	MD5 of Download.
TEST_MODE		used for CI
STARTUP_TIMEOUT	600	timeout for TEST_MODE

Additional Informations

Volumes

• /home/docker

Useful File Locations

• /home/docker/config/ Mod configs
• /home/docker/logs/ FTB logs
• /home/docker/mods/ Mod folder
• /home/docker/server.properties
• /home/docker/config.sh your personal config
• /home/addOp.sh script you can use for adding op.

add Operator

You can use the ingame command, if you don't like it: docker exec "CONTAINER" /home/addOp.sh "uuid" "name" "level" "bypassesPlayerLimit"

• uuid can be empty, will be resolved
• name is needed
• level if unset 4
• bypassesPlayerLimit if unset true
• docker restart CONTAINER needed

Use your existing server.properties

0. Step 1 & 2 can be done with copyToVolume.sh from tools section on git.
1. Create a volume where "server.properties" is at root location.
2. Set uid gid permissions on 10000.
3. start container with volume and -e OVERWRITE_PROPERTIES=false

persistent files on update

• banned-ips.json
• banned-players.json
• config.sh (if existing)
• ops.json
• server.properties
• usercache.json
• usernamecache.json
• whitelist.json

cleared on update

• mods/*
• config/*
• scripts/*
• structures/*

migrate server

You can use copyToVolume.sh from tools section on git. Examples below will result in a ready to go volume named "NewMCVolume". Download copyToVolume.sh, script is ash / bash compatible and only needs docker, no bind mount perm. needed.

Migration current status	Needed	Command	Result
Existing volume with your server files. Files are at VOLUME/server.properties	Name of the volume, MyMCVolume.	bash copyToVolume.sh MyMCVolume volume NewMCVolume 10000 10000	NewMCVolume is ready to go
Existing folder at host. Files are at FOLDER/server.properties	Path to the folder, /home/jusito/MCServer/server.properties.	bash copyToVolume.sh '/home/jusito/MCServer/*' path NewMCVolume 10000 10000	NewMCVolume is ready to go

Own Scripts

• /home/docker/config.sh, care because only alpine + busybox, no Bash, no PCRE

Minecraft related

• Set server image
• MOTD colors
• Whitelist usage ingame
• Op usage ingame

Resources needed / Problem resolve

4GB RAM and 4 CPUs with lower priority should be enough on a small server. In general you should set a container limit for CPU / RAM. --memory="4096m" --cpu-shares=1024 --cpus=4 --blkio-weight 125 If you use this, with the help of OpenJDK you can replace options like -Xmx4G -XX:ParallelGCThreads=5 -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10 with -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap OpenJDK Make JVM respect CPU and RAM limits OpenJDK will then make optimal use of the resources.

To understand whats wrong with your performance, you should know that the Garbage Collector (GC) in Java 8 stops everything if working. Thats because the default GC is for throughput not low latency, the default one in Java 8 is using only one thread for this. For example if you see lags ingame, like Mobs stopping for a second and are instant at your location, your problem is the GC. Java Low Latency If the lag occures like every second, you need more RAM -Xms -Xmx. If the lag isn't every second but very long, you want better multithreading for GC -XX:+UseParNewGC (FTB recommends this) or -XX:+UseG1GC (Oracle recommends this Oracle). This is basic stuff ofc there is a lot more, just search for "jvm low latency".

Is this working?

The label at the top of this document updates every week. If you want to test it on your own:

1. Clone Repository & install shellcheck
2. Navigate to root dir of repo
3. [Optional] Create Dockerfile for your modpack, just copy another FTB Dockerfile (if jar see vanilla, if zip see others, twitch forge see RLCraft), replace download & md5
4. bash test/testCaseQuick.sh "Vanilla-1.15.2" or bash test/testCaseAll.sh
5. [Optional] If you want more details, export DEBUGGING=true (xtrace activated everywhere)

Hint: If you want to test Modpack A in Version B, Dockerfile should be at "modpacks/A/B/Dockerfile" and you can test it with bash test/testCaseQuick.sh "A-B". For A:=Vanilla and B:=1.15.2 this would be "modpacks/Vanilla/1.15.2/Dockerfile" and image name used for testing "Vanilla-1.15.2".

FTP Server

• If your Volume is MyMinecraftVolume
• If you didn't change UserID / GroupID
• If you want to connect to ftp://...:123 (ports 122/123 are free on your network)

For FileZilla

docker run -d \
 -e MY_NAME="docker" -e MY_PASSWORD="MySecurePW" \
 -e MY_USER_ID="10000" -e MY_GROUP_ID="10000" \
 -p 122:20 -p 123:21 -p 10090-10100:10090-10100 \
 -v MyMinecraftVolume:/home/docker/ \
 jusito/vsftpd-alpine:simple

For Windows Network Mount

• IP of the Host (not container) 1.2.3.4
• Mount: ftp://1.2.3.4:123

docker run -d \
 -e MY_NAME="docker" -e MY_PASSWORD="MySecurePW" \
 -e MY_USER_ID="10000" -e MY_GROUP_ID="10000" \
 -p 122:20 -p 123:21 -p 10090-10100:10090-10100 \
 -v MyMinecraftVolume:/home/docker/ \
 -e pasv_address="1.2.3.4" \
 jusito/vsftpd-alpine:simple

Contributing / Requesting

Create a git issue or see maintainer label, I don't check everytime for newer version but I can easily push a new tag

Acknowledgments

• PurpleBooth@github Docker Template
• jamietech@github MC server status
• Valiano@stackoverflow ash grep behaviour
• Every mod / modpack creator, you sacrifice a lot of free time for our free time, thank you! Especially DDSS hooked me.