Autopause not working even though the interface is correct

[tomc128]

Describe the problem

I'm trying to use the autopause functionality. After setting it up to the best of my ability, it just won't work. I have set the interface to the only interface which appears in the container (eth0) but this doesn't work. It could possibly be something to do with the line sudo: you do not exist in the passwd database in the log file, but I'm unsure if this is the case, and if so how to solve it.

Container definition

services:
  survival:
    container_name: minecraft-survival
    image: itzg/minecraft-server
    expose:
      - "25565"
      - "25575"
    volumes:
      - "/mnt/data/games/minecraft/servers/survival/latest:/data"
    environment:
      EULA: 'TRUE'
      TYPE: PAPER
      MEMORY: 2G
      USE_AIKAR_FLAGS: 'TRUE'
      RCON_PASSWORD: [redacted]
      SKIP_SERVER_PROPERTIES: 'TRUE'
      OVERRIDE_SERVER_PROPERTIES: 'TRUE'
      
      # Server Properties
      MAX_PLAYERS: 5
      ENABLE_COMMAND_BLOCK: 'TRUE'
      ONLINE_MODE: 'FALSE'
      
      # Autopause
      MAX_TICK_TIME: '-1'
      JVM_DD_OPTS: 'disable.watchdog:true'
      ENABLE_AUTOPAUSE: 'TRUE'
      AUTOPAUSE_KNOCK_INTERFACE: 'eth0' # eth0 is the only interface which shows in the docker container
      AUTOPAUSE_TIMEOUT_EST: '60'
      AUTOPAUSE_TIMEOUT_INIT: '60'

    user: '1001:1001'
    restart: unless-stopped
    stdin_open: true
    tty: true

Container logs

minecraft-survival  | [init] Running as uid=1001 gid=1001 with /data as 'drwxrwxr-x 12 1001 1001 4096 Jun 23 22:38 /data'
minecraft-survival  | [init] Autopause functionality enabled
minecraft-survival  | [init] Resolving type given PAPER
minecraft-survival  | sudo: you do not exist in the passwd database
minecraft-survival  | [Autopause loop] Failed to start knockd daemon.
minecraft-survival  | [Autopause loop] Probable cause: Unable to attach to interface "eth0".
minecraft-survival  | [Autopause loop] Available interfaces within the docker container:
minecraft-survival  | [Autopause loop]   eth0
minecraft-survival  | [Autopause loop] Please set the environment variable AUTOPAUSE_KNOCK_INTERFACE to the interface that handles incoming connections.
minecraft-survival  | [Autopause loop] If unsure which interface to choose, run the ifconfig command in the container.
minecraft-survival  | [Autopause loop] Autopause failed to initialize. This log entry will be printed every 30 minutes.
minecraft-survival  | [mc-image-helper] 22:44:43.002 INFO  : Resolved paper to version 1.20.1 build 47
minecraft-survival  | [mc-image-helper] 22:44:43.130 INFO  : The file /data/paper-1.20.1-47.jar is already up to date
minecraft-survival  | [init] Skipping setup of server.properties
minecraft-survival  | [init] Warning: The server.properties for the server doesn't have the Server Watchdog (effectively) disabled.
minecraft-survival  | [init]          Autopause functionality resuming the process might trigger the Watchdog and restart the server completely.
minecraft-survival  | [init]          Set the MAX_TICK_TIME env variable (or max-tick-time property) to a high value (or disable the Watchdog with value -1 for versions 1.8.1+).
minecraft-survival  | [init] Updating ops
minecraft-survival  | [init] tomc128 already present in ops.json, skipping
minecraft-survival  | [init] Updating whitelist
minecraft-survival  | [init] tomc128 already present in whitelist.json, skipping
minecraft-survival  | [init] Using Aikar's flags
minecraft-survival  | [init] Setting initial memory to 2G and max to 2G
minecraft-survival  | [init] Starting the Minecraft server...
minecraft-survival  | Starting org.bukkit.craftbukkit.Main
minecraft-survival  | System Info: Java 17 (OpenJDK 64-Bit Server VM 17.0.7+7) Host: Linux 5.15.0-75-generic (amd64)
minecraft-survival  | Loading libraries, please wait...
minecraft-survival  | 2023-06-23 22:44:48,504 ServerMain WARN Advanced terminal features are not available in this environment
minecraft-survival  | [22:44:52 INFO]: Environment: authHost='https://authserver.mojang.com', accountsHost='https://api.mojang.com', sessionHost='https://sessionserver.mojang.com', servicesHost='https://api.minecraftservices.com', name='PROD'
minecraft-survival  | [22:44:53 INFO]: Loaded 7 recipes
minecraft-survival  | [22:44:53 INFO]: Starting minecraft server version 1.20.1
minecraft-survival  | [22:44:53 INFO]: Loading properties
minecraft-survival  | [22:44:54 INFO]: This server is running Paper version git-Paper-47 (MC: 1.20.1) (Implementing API version 1.20.1-R0.1-SNAPSHOT) (Git: aea9cdd)
minecraft-survival  | [22:44:54 INFO]: Server Ping Player Sample Count: 12
minecraft-survival  | [22:44:54 INFO]: Using 4 threads for Netty based IO
minecraft-survival  | [22:44:54 WARN]: [!] The timings profiler has been enabled but has been scheduled for removal from Paper in the future.
minecraft-survival  |     We recommend installing the spark profiler as a replacement: https://spark.lucko.me/
minecraft-survival  |     For more information please visit: https://github.com/PaperMC/Paper/issues/8948
minecraft-survival  | [22:44:54 INFO]: [ChunkTaskScheduler] Chunk system is using 1 I/O threads, 3 worker threads, and gen parallelism of 3 threads
minecraft-survival  | [22:44:54 INFO]: Default game type: SURVIVAL
minecraft-survival  | [22:44:54 INFO]: Generating keypair
minecraft-survival  | [22:44:54 INFO]: Starting Minecraft server on *:25565
minecraft-survival  | [22:44:54 INFO]: Using epoll channel type
minecraft-survival  | [22:44:54 INFO]: Paper: Using libdeflate (Linux x86_64) compression from Velocity.
minecraft-survival  | [22:44:54 INFO]: Paper: Using OpenSSL 1.1.x (Linux x86_64) cipher from Velocity.
minecraft-survival  | [22:44:54 INFO]: Server permissions file permissions.yml is empty, ignoring it
minecraft-survival  | [22:44:54 INFO]: Preparing level "world"
minecraft-survival  | [22:44:54 INFO]: Preparing start region for dimension minecraft:overworld
minecraft-survival  | [22:44:55 INFO]: Time elapsed: 163 ms
minecraft-survival  | [22:44:55 INFO]: Preparing start region for dimension minecraft:the_nether
minecraft-survival  | [22:44:55 INFO]: Time elapsed: 44 ms
minecraft-survival  | [22:44:55 INFO]: Preparing start region for dimension minecraft:the_end
minecraft-survival  | [22:44:55 INFO]: Time elapsed: 34 ms
minecraft-survival  | [22:44:55 INFO]: Running delayed init tasks
minecraft-survival  | [22:44:55 INFO]: Done (1.255s)! For help, type "help"
minecraft-survival  | [22:44:55 INFO]: Timings Reset

[itzg]

I guess that code needs to fail sooner. The real error is

minecraft-survival  | sudo: you do not exist in the passwd database
minecraft-survival  | [Autopause loop] Failed to start knockd daemon.

I'm guessing that's because you're running the whole container as uid 1001, but knockd needs to start as root. The script switches soon after to a non-root user FWIW.

[tomc128]

Thanks for your reply, removing the user line fixed the problem and it works now.